武汉大学生命科学学院, 梁子湖湖泊生态系统国家野外科学观测研究站, 武汉 430072
版权声明: 2016 植物生态学报编辑部 本文是遵循CCAL协议的开放存取期刊，引用请务必标明出处。
基金资助:
展开
摘要
水位波动对水生植物的生长有显著影响。该文通过设置0次(对照)、1次、2次和4次水位波动频率, 研究了入侵种喜旱莲子草(Alternanthera philoxeroides)、外来种粉绿狐尾藻(又称聚叶狐尾藻, Myriophyllum aquaticum)和乡土种水龙(Ludwigia adscendens = Jussiaea reppens)对水位波动的形态和生理响应策略。结果显示: 水位波动对喜旱莲子草的分枝数、根冠比和最大光化学量子产量(Fv/Fm)无明显影响, 但明显增加了株高(水位波动1次除外), 降低了生物量和叶绿素含量; 粉绿狐尾藻的分枝数和Fv/Fm在不同水位波动下无明显变化, 但株高在2次水位波动下明显增加, 根冠比在1次和4次水位波动下明显增加, 生物量和叶绿素含量(4次水位波动除外)在水位波动后明显降低; 水位波动明显降低了水龙的分枝数(2次水位波动除外)、株高(1次和2次水位波动除外)、总生物量(2次水位波动除外)和叶绿素含量, 但对水龙的根冠比和Fv/Fm无明显影响。水龙的分枝数、株高、总生物量、叶绿素含量和Fv/Fm在绝大部分水位波动处理下都明显大于喜旱莲子草和粉绿狐尾藻, 而且后二者间没有显著区别。以上结果说明在秋季这3个物种的生长都受到水位波动的抑制, 喜旱莲子草和粉绿狐尾藻在秋季水位波动生境中并不能表现出较强的生长能力, 但对水位波动具有较强的耐受性和可塑性, 这与入侵种较强的入侵性有关。应加强防范外来种粉绿狐尾藻的入侵。
关键词：
Abstract
In wetlands, water levels can fluctuate, which often disturbs local organisms, such as aquatic plants. The responses of Alternanthera philoxeroides, Myriophyllum aquaticum, and Ludwigia adscendens to water level fluctuations of different frequencies were examined here.
Water level fluctuations were simulated at four frequencies: static (0 frequency), one cycle (1 frequency), two cycles (2 frequency), and four cycles (4 frequency), and with fluctuation amplitudes (± 25 cm) during a 60 day experiment. Morphological and physiological traits of plants, including branching number, shoot length, total biomass, shoot root ratio, chlorophyll content, and maximum PSII quantum efficiency(Fv/Fm) were assessed.
Water level fluctuation was found to have no significant impact on branching number, root shoot ratio, or Fv/Fm of A. philoxeroides,but all scenarios except 1 frequency were significantly associated with longer shoots and lower total biomass and chlorophyll content. The traits of M. aquaticumshowed different responses to water level fluctuation: branching number and Fv/Fm showed no changes, but shoot length (2 frequency) and root shoot ratio (1 and 4 frequency) increased significantly, and total biomass and chlorophyll content (expect 4 frequency) decreased. In L. adscendens, water level fluctuation was associated with lower branching number in all scenarios except 2 frequency, shoot length in all scenarios except 1 and 2 frequency, total biomass in all scenarios except 2 frequency, and chlorophyll content but had no significant effects on root shoot ratio or Fv/Fm. Under most water level fluctuation conditions, the branching number, shoot length, total biomass, chlorophyll content, and Fv/Fm of L. adscendens were significant higher than those of A. philoxeroides and M. aquaticum, and the latter two had no significant differences.
suggested that water level fluctuations were the limiting factor for the growth of three species in autumn. Alternanthera philoxeroides and M. aquaticumdid not show higher invasiveness in environments in which the water level fluctuated in autumn but did show higher tolerance and plasticity in response to water level fluctuations in general. This was related to the invasiveness of introduced species.
also indicated that preventive efforts focusing on potential invasion by M. aquaticum should be strengthened.
Keywords：
水位波动现象在人工湖中最为明显, 在天然湖泊的大尺度范围内, 包括季节和年际尺度上, 水位波动也经常发生(Gasith & Gafny, 1990), 这主要是由于气候和水文胁迫导致的(Zohary & Ostrovsky, 2011)。在未来全球气候变暖的背景下, 洪水可能会发生得更加频繁(Houghton et al., 2001)。气候异常波动会加剧干旱和洪涝的程度(方精云, 2000), 从而进一步加大湖泊水位波动的周期和范围(Magnuson et al., 1997)。水位波动是水文情势的一个组成部分。水文情势可以由湿地中的水深、水位持续时间、水位波动频率、水体的补充和干涸速率、淹水和干涸的时间, 以及可预测性来描述(Yu & Yu, 2009)。水位波动作为湿地中常见的干扰因子, 对外来种入侵也有明显影响。例如, 有过水文干扰历史的湿地具有更多的入侵现象, 干扰加速了外来种向湿地的入侵(Sobrino et al., 2002)。
水位变化对不同的水生植物有不同影响。挺水植物芦苇(Phragmites australis)幼苗在水淹没状态下, 其节间距会增长, 而在水位下降后其种子有很高的萌发率(Maucham et al., 2001)。濒危沉水植物水车前(又称龙舌草) (Ottelia alismoides)的叶片特征(叶片数和叶面积)和生物量分配类型在恒定水位和波动水位之间呈现整体的相似性(Yu & Yu, 2009)。浮叶植物荇菜(Nymphoides peltata)在水位缓涨的处理中显示出了与恒定水位相似的生物量和克隆株数, 但是水位骤涨却大大降低了荇菜植株的克隆株数(Yu & Yu, 2011)。前人有关水位波动与水生植物关系的研究多是在夏季开展的(Strand & Weisner, 2001; 杨永清, 2003; Yu & Yu, 2009, 2011), 而有关秋季水位波动的研究还较少, 尤其是对扎根漂浮生长的入侵种和外来种影响的研究更少。
水生型喜旱莲子草(Alternanthera philoxeroides)、粉绿狐尾藻(Myriophyllum aquaticum)和水龙(Ludwigia adscendens = Jussiaea reppens)虽以漂浮生长为主, 但多是扎根在水体沿岸带的基底, 其漂浮层一方面是由湿生型匍匐茎伸展到水面交错形成的, 另一方面是由湿生型在遭受淹水后先进行沉水生长, 随着匍匐茎生长伸长至水面继而进行扎根漂浮生长而形成的。本实验设置了不同的水位波动频率, 以扎根挺水生长的喜旱莲子草、粉绿狐尾藻和水龙为研究对象, 观测了水位波动对相似生活型的入侵种、外来种和本地种的影响, 拟解决以下两个问题: (1)入侵种、外来种和本地种如何适应水位波动?(2)水位波动频率的增加会不会促进外来种和入侵种的入侵?本实验试图为管理和控制入侵种和预测外来种的入侵提供一定的理论依据。
本实验在梁子湖湖泊生态系统国家野外科学观测研究站(30.18°-30.30° N, 114.35°-114.58° E)完成。梁子湖(30.08º-30.30º N, 114.35º-114.65º E)是湖北省第二大湖,平均水深4.2 m; 湖区属于北亚热带季风气候, 年平均温度为16.8 ℃ (王苏民和窦鸿身, 1998)。本实验选取的水生植物材料包括喜旱莲子草、粉绿狐尾藻和水龙。喜旱莲子草是国家环保总局于2002年公布的9种危害最大的外来入侵植物(潘晓云等, 2006), 主要分布在黄河流域以南, 尤以长江流域为多, 即主要分布在我国亚热带地区, 暖温带半湿润以及热带地区偶有发生(郭水良和李扬汉, 1998)。该种既可陆生又可水生, 水生型以漂浮生长为主, 也可以在较长时间内淹水生长(Fan et al., 2015)。粉绿狐尾藻原产于南美亚马逊河流域, 现已分布于全世界大部分地区(Li & Hsieh, 1996), 多漂浮生长, 也可挺水或沉水生长, 植株沉水时茎半直立生长, 上部为挺水叶, 匍匐在水面上, 下半部为水中茎(Hussner et al., 2009)。因其具有观赏价值和容易培育, 常见于水族馆。目前粉绿狐尾藻在我国的花鸟鱼市场常见, 并在水污染治理和水体景观绿化中应用(吴程等, 2008; 王文国等, 2013)。水龙主要分布于热带和亚热带地区, 在我国长江以南亚热带湿润地区均有分布。水龙通常生长在沟渠、溪流、浅水池塘和稻田等生境, 多以扎根漂浮生长为主, 在淹水条件下仍能沉水生长(Li et al., 2008; You et al., 2014)。
2013年8月, 采集喜旱莲子草、粉绿狐尾藻和水龙的顶端断枝10 cm (在同一湿生环境的同生群中), 统一培养于以河沙为基质的实验盆中, 保持植物挺水生长, 定期浇水。一周后, 断枝生根, 所有培养材料均视作植株幼苗, 用于本实验。三种植物的幼苗平均株高为20 cm, 平均鲜质量(平均值±标准误差)分别为: 喜旱莲子草(2.695 ± 0.282) g, 粉绿狐尾藻(3.357 ± 0.404) g, 水龙(3.576 ± 0.278) g。每株幼苗移栽到以湖泥为基质的实验黑桶(直径25 cm, 高15 cm)中, 将黑桶用绳子吊于水泥池(4 m × 4 m × 4 m)的钢管上, 使植株保持挺水且部分匍匐生长状态。一周后, 将黑桶调整至水下50 cm。植株在50 cm的水位下稳定生长一周, 然后进行不同的水位波动处理。实验周期内, 设置对照(0次波动, 水位50 cm), 3个水位波动频率(1次, 2次, 4次), 围绕50 cm水位波动幅度为±25 cm, 从低水位开始到高水位结束。1次波动是指在实验周期60天内, 先在初始50 cm水深处保持10天, 然后降低水位至25 cm处保持20天, 然后再增加水位至50 cm保持10天, 继续增加水位至75 cm保持20天至实验结束; 2次波动是指在实验周期60天内, 先在初始50 cm水深处保持5天, 然后降低水位至25 cm处, 10天后再增加水位至50 cm处保持5天, 继续增加水位至75 cm处保持10天, 由此完成1次波动, 在实验周期内共实施2次这样的波动; 4次波动是指在实验周期60天内, 先在水深50 cm处保持2.5天, 然后降低水深至25 cm, 5天后增加水深至50 cm处, 保持2.5天, 继续增加水深至75 cm处保持5天, 按这个顺序在实验周期内重复4次波动(图1)。每个实验处理20个重复。实验期间定期加水和清理水泥池中的水绵, 进行日常实验维护; 并每隔两天监测早、中、晚三个时间段的水体物理化学指标(表1)。
表1 实验期间水体物理化学指标(平均值±标准误差)
Table 1 The physical and chemical index of the water during the experiment (means ± SE)
| 温度 Temperature (℃) | 溶解氧 Dissolved oxygen (mg·L-1) | 电导率 Conductivity (ms·m-1) | 溶解性固体总量 Total dissolved solids (mg·L-1) | 盐度 Salinity (%) | pH值 pH value | 水面光照 Light intensity on water surface (μmol·m-2·s-1) |
|---|---|---|---|---|---|---|
| 29.36 ± 2.86 | 5.06 ± 1.18 | 192.26 ± 16.52 | 115.32 ± 7.86 | 0.008 0 ± 0.000 6 | 8.79 ± 0.14 | 851.54 ± 322.38 |
收获时, 轻轻将植株根部的土壤洗去, 统计植株分枝数, 测量株高, 然后将植株地上和地下部分分开, 置于70 ℃烘箱中烘烤72 h后称量, 计算生物量。根冠比通过地下生物量和地上生物量的比值来计算。
根据Lichtenthaler (1987)的方法测定总叶绿素含量。在实验收获前使用水下调制叶绿素荧光仪(DIVING-PAM, Walz, Effeltrich, Germany)和数据采集软件wincontrol (Walz GmbH, Effeltrich, Germany)测定光系统II (PSII)最大光化学量子产量(Fv/Fm)。2013年10月28日7:00-8:30, 取喜旱莲子草和水龙植株顶端以下完全伸展的第三片叶、粉绿狐尾藻植株顶端以下第四轮长势浓密的羽状裂叶, 小心地放进水下调制叶绿素荧光仪叶夹中, 用叶夹夹住进行15 min暗适应后, 打开叶夹, 用测量光测出初始荧光(F0), 然后打开一个饱和脉冲测量最大荧光(Fm)。根据计算公式Fv/Fm = (Fm - F0)/Fm, 计算出Fv/Fm。 虽然粉绿狐尾藻的叶片是羽状裂叶, 但前人采用水下调制叶绿素荧光仪(Walz GmbH, Effeltrich, Germany)测量了狐尾藻(Myriophyllum verticillatum)和穗花狐尾藻(M. spicatum)的Fv/Fm (宋玉芝等, 2010; 经博翰和袁龙义, 2015) , 因此我们也用此仪器测量了粉绿狐尾藻的Fv/Fm。
为了满足实验数据的正态分布和方差齐性, 对有些不满足正态分布和方差齐性的数据先进行对数转换后再进行分析。利用双因素方差分析(two-way ANOVA)来评估水位波动的频率和物种对分枝数、株高、生物量、根冠比、叶绿素含量和Fv/Fm的影响。如果处理的影响是显著的, 再利用Tukey-s-b(K)多重比较方法检验处理间的差异。实验中显著度的水平为0.05。数据分析使用SPSS 18.0软件。
虽然双因素方差分析表明水位波动频率显著地影响了分枝数(表2), 但喜旱莲子草和粉绿狐尾藻的分枝数在不同的水位波动频率下无明显变化, 只有水龙的分枝数在2次水位波动下明显大于1次和4次的, 而在4次水位波动频率下的分枝数最小(图2A)。物种间的分枝数差异明显, 除4次水位波动外, 在对照、1次和2次水位波动下, 水龙的分枝数都明显大于其他两种; 而在所有的水位波动处理下喜旱莲子草和粉绿狐尾藻的分枝数都没有显著区别(表2; 图2A)。
表2 水位波动和物种对形态特征和生理特征影响的方差分析
Table 2 F and p values for two-way ANOVA of water level and species analysis for morphological and physiological traits
| 方差来源 Source of variation | 处理 Treatment | 物种 Species | 处理×物种 Treatment × species |
|---|---|---|---|
| 分枝数 Branching number | 46.496*** | 57.285*** | 110.719*** |
| 株高 Shoot length | 11.593** | 116.742*** | 136.719*** |
| 总生物量 Total biomass | 35.962*** | 74.402*** | 122.205*** |
| 根冠比 Root shoot ratio | 0.946ns | 0.932ns | 8.460*** |
| 叶绿素含量 Chlorophyll content | 19.405*** | 16.379*** | 45.39*** |
| 最大光化学量子产量 Maximum PSII quantum efficiency | 6.934ns | 93.935*** | 106.524*** |
不同物种的株高明显受水位波动的影响(表2)。喜旱莲子草的株高随着水位波动频率增加而增大, 但对照和1次波动处理以及2次和4次波动处理之间无明显区别。粉绿狐尾藻的株高只有在2次波动下明显升高, 其余水位波动处理下无明显变化。水龙的株高在4次波动处理时明显降低(图2B)。不同物种间的株高差异显著(表2); 在对照、1次和2次水位波动时水龙株高都是明显大于喜旱莲子草和粉绿狐尾藻的, 而且后二者间无明显区别; 在4次水位波动时水龙与喜旱莲子草的株高无明显区别, 但都明显大于粉绿狐尾藻的(图2B)。
图2 喜旱莲子草、粉绿狐尾藻和水龙的分枝数(A)、株高(B)、总生物量(C)、根冠比(D)、叶绿素含量(E)和最大光化学量子产量(F)在不同水位波动频率下的变化(平均值±标准误差, n = 20)。相同的字母表示处理间无显著差异(p > 0.05); 不同的字母表示处理间差异显著(p < 0.05)。
Fig. 2 Branching number (A), shoot length (B), total biomass (C), root shoot ratio (D), content of chlorophyll (E) and maximum PSII quantum efficiency (F) of Alternanthern philoxeroides, Myriophyllum aquaticum and Ludwigia adscendens subjected to the different frequency of water-level fluctuation (mean ± SE, n = 20). Bars sharing the same letters indicate no significant differences among treatments (p > 0.05) and the different letters indicate significant differences among treatments (p < 0.05).
不同物种的总生物量明显受水位波动的影响(表2); 水位波动明显降低了喜旱莲子草的总生物量, 但波动频率(1次、2次和4次)间无明显差异; 水位波动同样明显降低了粉绿狐尾藻的总生物量, 但2次波动处理下的总生物量明显大于1次和4次的, 而后二者间无明显差异; 1次和4次波动处理明显降低了水龙的总生物量, 而2次波动处理和对照无明显区别(图2C)。不同物种间的总生物量之间有显著差异(表2)。水龙的总生物量在所有处理下都显著大于其他两种; 对照和4次波动下的喜旱莲子草总生物量分别明显小于和大于粉绿狐尾藻的总生物量, 1次和2次波动下无明显区别(图2C)。
喜旱莲子草和水龙的根冠比在所有水位处理下都无明显变化; 粉绿狐尾藻的根冠比在1次和4次波动下明显大于对照, 2次波动与对照无明显区别, 而且1次、2次和4次波动间无明显区别; 此外, 不同物种间的根冠比没有明显差异(表2; 图2D)。
不同物种的叶绿素含量明显受水位波动的影响(表2); 所有的水位波动处理下喜旱莲子草和水龙叶绿素含量都明显小于对照, 但1次、2次和4次波动频率间无明显区别; 1次和2次波动处理明显降低了粉绿狐尾藻的叶绿素含量, 而4次波动处理与对照无明显区别(图2E)。不同物种间的叶绿素也有明显差异; 对照组的喜旱莲子草和水龙的叶绿素含量显著大于粉绿狐尾藻的, 前两者之间差异不显著; 1、2次水位波动处理下, 水龙的叶绿素含量均明显大于喜旱莲子草和粉绿狐尾藻的叶绿素含量, 而后二者间没有明显差异; 4次水位波动频率下水龙与粉绿狐尾藻的叶绿素含量无明显区别, 且都显著大于喜旱莲子草(表2; 图2E)。
不同水位波动处理对Fv/Fm无明显影响, 但物种间的Fv/Fm差异显著; 在所有的水位波动处理下水龙的Fv/Fm值都显著大于喜旱莲子草和粉绿狐尾藻, 后二者之间没有显著差异(表2; 图2F)。
杨永清(2003)对沉水植物响应水位波动的研究发现, 水位恒定时轮叶黑藻(Hydrilla verticillata)的分枝数大于水位波动时; 微齿眼子菜(Potamogeton maackianus)和穗花狐尾藻在水位波动时分枝数无明显变化。同样, 本实验发现喜旱莲子草和粉绿狐尾藻的分枝数不受水位波动的影响, 但低频率和高频率的水位波动都降低了水龙的分枝数, 说明只有适度的水位波动对水龙的分枝数不产生影响。耐淹水植物对淹水胁迫的响应主要有逃离和忍耐两个策略, 其中逃离策略主要是通过叶柄、茎或叶片的伸出而逃离淹水, 以达到植株伸出水面获得充足空气的目的(Vartapetian & Jackson, 1997; Mommer & Visser 2005; Bailey-Serres & Voesenek, 2008)。在本实验中, 相对于恒定水位, 波动水位实际上在一定时间内增加了植株淹水的程度, 相比于对照, 2次波动下喜旱莲子草和粉绿狐尾藻的株高明显增加, 4次波动处理只明显增加了喜旱莲子草的株高, 但水龙的株高在4次水位波动下明显降低, 这说明入侵种喜旱莲子草以比较高的形态可塑性来适应水位波动的胁迫, 外来种粉绿狐尾藻只有在中等水位波动下有较强的形态适应能力, 而乡土种水龙对水位波动适应性差。
水位波动对不同水生植物的生物量产生不同影响。如对沉水植物而言, 光照可能是主要的限制因子(Yu & Yu, 2009), 不同的沉水植物对光的需求不同, 因此对水位波动的响应也不同。如水位波动对穗花狐尾藻的生物量无明显影响, 但使微齿眼子菜的生物量明显增加、轮叶黑藻和水车前生物量显著降低(杨永清, 2003; Yu & Yu, 2009)。不同于沉水植物, 本实验的3个物种在野外多以漂浮生长为主, 本实验中是以扎根挺水状态生长, 而水位波动造成了一定的淹水, 尤其是水位上升25 cm时大部分茎淹没在水中。随着水淹时间的延长, 植株对大气CO2、O2及土壤养分利用的能力急剧减弱, 从而加剧了植株本身营养物质的消耗, 导致植株生物量显著降低(Crawford & Brändle, 1996; Vartapetian & Jackson, 1997)。因此, 在本实验中除了水龙的2次波动处理, 水位波动都明显降低了三物种的总生物量。
面对水位变化, 植物通常会产生形态可塑性以及改变地下生物量和地上生物量的分配样式确保生存(魏华等, 2010)。生活在变化生境中的植物, 其生物量分配模式的可塑性是一种适应对策(McCo- nnaughay & Coleman, 1999), 而这种自我调节的变化结果, 往往符合最优分配理论的预测(Wright & McConnaughay, 2002), 以最大化获取光、营养和水等受限资源(McConnaughay & Coleman, 1999)。在频繁扰动的生境中, 植物将会分配更多的资源到抗干扰的器官中(Barrat-Segretain, 2001)。在本实验中, 喜旱莲子草和水龙的根冠比在所有水位处理下都无明显变化, 而粉绿狐尾藻的根冠比在1次和4次波动下明显大于对照。这可能是由于前两种既能扎根生长又能漂浮生长, 而且在沉水状态时并不形成特定的沉水叶, 在应对水位波动时不需要再投入更多能量来增加地下根的生长; 相反, 粉绿狐尾藻在沉水状态时有特定的沉水叶形成(Sutton & Bingham, 1973), 而沉水叶的形成势必要增加营养物质的消耗, 因此在水位波动时(相对于恒定水位, 增加了淹水时间)需增强根的生长来提高对营养物质的吸收, 从而导致根生物量分配的增加。
许多研究表明, 在淹水状态下, 湿生植物的叶绿素含量明显下降(Chen et al., 2005; 袁琳等, 2010)。在本实验中, 相对于恒定水位, 水位波动处理增加了植物淹水的时间和强度, 因此水位波动明显降低了3种植物的叶绿素含量, 只有粉绿狐尾藻在高频率(4次)波动处理时与对照无明显区别(图2E), 这可能是由于水位变化的频率较高, 植物来不及适应任何一个水位(Yu & Yu, 2009), 因此粉绿狐尾藻在高频率(4次)波动处理时叶绿素含量并没有发生变化。
饱和脉冲调制叶绿素荧光技术是一种快速、无损伤研究植物光合作用的技术, 不伤害植物叶片就可以测定一系列光合荧光参数(Schreiber et al., 1995)。Fv/Fm反映了植物潜在最大光合速率, 该值在非胁迫条件下参数变化极小, 植物受到胁迫时显著下降。在适宜条件下, 大部分植物的Fv/Fm范围在0.75到0.85之间(Björkman & Demmig, 1987)。持续淹水胁迫使野古草( Arundinella anomala)(又称毛秆野古草(Arundinella hirta))和入侵植物互花米草(Spartina alterniflora)的Fv/Fm明显降低(罗芳丽等, 2006; 袁琳等, 2010)。在本实验中, 喜旱莲子草、粉绿狐尾藻和水龙各个处理中Fv/Fm没有显著变化, 且均在正常范围内, 表明本实验中的水位波动对喜旱莲子草、粉绿狐尾藻和水龙的潜在光合作用能力没有形成胁迫。
许多研究表明外来种的光合能力强于本地种(McDowell, 2002; 郑丽和冯玉龙, 2005; 王晓红和纪明山, 2013), 从而有助于其入侵和扩散。相反, 在本研究中发现, 在恒定水位和4次水位波动下, 水龙与喜旱莲子草和粉绿狐尾藻的叶绿素含量均无明显差异, 在1次和2次水位波动下, 水龙的叶绿素含量都明显大于喜旱莲子草和粉绿狐尾藻的, 另外在对照和各水位波动下水龙的Fv/Fm都明显大于喜旱莲子草和粉绿狐尾藻的, 这些都表明本地种水龙的叶片潜在光合能力要强于入侵种和外来种。这有可能是因为我们的研究是在秋季, 并不是喜旱莲子草和粉绿狐尾藻的最佳生长季节, 其潜在光合能力较低。
相对于恒定水位, 喜旱莲子草的分枝数、根冠比和Fv/Fm不受水位波动的影响, 且以增加株高来响应不同频率的水位波动。粉绿狐尾藻以不变的分枝数和Fv/Fm, 增加的株高和根冠比来响应不同频率的水位波动, 说明这两种植物对水位波动都具有一定的耐受性和可塑性, 这些特性有可能促进其入侵; 相反, 水龙对低频率和高频率的水位波动的适应能力较弱, 在高频率的水位波动下, 其分枝数、株高和叶绿素含量均明显降低。虽然喜旱莲子草和粉绿狐尾藻在响应水位波动时其耐受性和可塑性强于水龙, 但是不同频率的水位波动都明显降低了前二者的生物量, 而水龙的生物量只在低频率和高频率水位波动下明显降低, 而且在绝大部分水位波动频率下, 相对于喜旱莲子草和粉绿狐尾藻, 水龙具有较高的分枝数、株高、生物量、叶绿素含量和Fv/Fm, 这些结果说明在秋季水位波动条件下乡土种水龙具有一定的生长优势, 而入侵种喜旱莲子草和外来种粉绿狐尾藻的生长却受到抑制。
致谢 感谢武汉大学、梁子湖湖泊生态系统国家野外科学观测研究站的刘俊初、王亚林和李茜同学在实验工作中给予的帮助。
The authors have declared that no competing interests exist.
作者声明没有竞争性利益冲突.
| [1] |
Flooding stress: Acclimations and genetic diversity. https://doi.org/10.1146/annurev.arplant.59.032607.092752 URL PMID: 18444902 [本文引用: 1] 摘要
Abstract Flooding is an environmental stress for many natural and man-made ecosystems worldwide. Genetic diversity in the plant response to flooding includes alterations in architecture, metabolism, and elongation growth associated with a low O(2) escape strategy and an antithetical quiescence scheme that allows endurance of prolonged submergence. Flooding is frequently accompanied with a reduction of cellular O(2) content that is particularly severe when photosynthesis is limited or absent. This necessitates the production of ATP and regeneration of NAD(+) through anaerobic respiration. The examination of gene regulation and function in model systems provides insight into low-O(2)-sensing mechanisms and metabolic adjustments associated with controlled use of carbohydrate and ATP. At the developmental level, plants can escape the low-O(2) stress caused by flooding through multifaceted alterations in cellular and organ structure that promote access to and diffusion of O(2). These processes are driven by phytohormones, including ethylene, gibberellin, and abscisic acid. This exploration of natural variation in strategies that improve O(2) and carbohydrate status during flooding provides valuable resources for the improvement of crop endurance of an environmental adversity that is enhanced by global warming.
|
| [2] |
Biomass allocation in three macrophyte species in relation to the disturbance level of their habitat. https://doi.org/10.1046/j.1365-2427.2001.00728.x URL [本文引用: 1] 摘要
1. The hypothesis was tested that perennial plants surviving in habitats frequently disturbed by floods should demonstrate the ability to escape the frequently scoured surficial zone by using refugia located deeper in the substrate. As a consequence, they should allocate more biomass to their underground parts than when growing in rarely disturbed habitats. 2. The allocation of biomass of three aquatic macrophytes ( Berula erecta , Groenlandia densa , Myriophyllum spicatum ) to their different organs (underground and above-ground parts) was measured in former river channels organized along a gradient of scouring flood disturbances. 3. For each species, biomass allocation to underground parts varied between sites: from 10.2 to 37.5% in B. erecta , from 14.9 to 31.1% in G. densa and from 8.4 to 23.2% in M. spicatum . It was correlated to the flood disturbance level of the site for B. erecta and M. spicatum but not for G. densa. No relationship was found between biomass allocation to underground parts and sediment richness. 4. The plasticity in biomass allocation of these three macrophyte species appears to be an adaptation to the variability in environmental conditions and implies difficulties in the classification of plant primary strategies, when this type of plasticity is ignored.
|
| [3] |
Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77 K among vascular plants of diverse origins. |
| [4] |
Effects of soil flooding on photosynthesis, carbohydrate partitioning and nutrient uptake in the invasive exotic |
| [5] |
Oxygen deprivation stress in a changing environment. https://doi.org/10.1093/jxb/47.2.145 URL [本文引用: 1] 摘要
Past research into flooding tolerance and oxygen shortages in plants has been motivated largely by cultivation problems of arable crops. Unfortunately, such species are unsuitable for investigating the physiological and biochemical basis of anoxia-tolerance as selection has reduced any tolerance of anaerobiosis and anaerobic soil conditions that their wild ancestors might have possessed. Restoration of anoxia-tolerance to species that have lost this property is served better by physiological and molecular studies of the mechanisms that are employed in wild species that still possess long-term anoxia-tolerance. Case studies developing these arguments are presented in relation to a selection of crop and wild species. The flooding sensitivity and metabolism of maize is compared in relation to rice in its capacity for anaerobic germination. The sensitivity of potato to flooding is related to its disturbed energy metabolism and inability to maintain functioning membranes under anoxia and postinoxia. By contrast, long-term anoxia-tolerance in the American cranberry ( Vaccinium macrocarpon ) and the arctic grass species Deschampsia beringensis can be related to the provision and utilization of carbohydrate reserves. Among temperate species, the sweet flag ( Acorus calamus ) shows a remarkable tolerance of anoxia in both shoots and roots and is also able to mobilize carbohydrate and maintain ATP levels during anoxia as well as preserving membrane lipids against anoxic and post-anoxic injury. Phragmites australis and Spartina alterniflora, although anoxia-tolerant, are both sulphide-sensitive species which can pre-dispose them to the phenomenon of die-back in stagnant, nutrient-rich water. Glyceria maxima adapts to flooding through phenological adaptations with a seasonal metabolic tolerance of anoxia confined to winter and spring which, combined with a facility for root aeration and early spring growth, allows rapid colonization of sites with only shallow flooding. The diversity of responses to flooding in wild plants suggests that, depending on the life strategy and habitat of the species, many different mechanisms may be involved in adapting plants to survive periods of inundation and no one mechanism on its own is adequate for ensuring survival.
|
| [6] |
The effects of complete submergence on the morphological and biomass allocation response of the invasive plant https://doi.org/10.1007/s10750-014-2005-3 URL [本文引用: 1] 摘要
Climate change may lead to more intense and frequent flooding. Alternanthera philoxeroides is a perennial that grows rapidly in both terrestrial and aquatic habitats. However, there is a lack of information about whether this species survive or not under flooded conditions, especially when completely submerged. In this study, the effect of submergence at depths of 0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0m on the growth of A. philoxeroides was investigated. The results showed that submergence decreased the growth of A. philoxeroides but allowed 100% survival. Because of increased shoot length when submerged at the 0.5m depth for 2weeks, 62.5% of plants grew above the water. Elongation of shoots and internodes, higher specific leaf area ratio, the leaf weight ratio and stem diameters, development of new leaves (not at depths deeper than 1.0m), and adventitious roots at all depths were tolerance strategies of A. philoxeroides in response to submergence. These strategies suggest that this species is highly tolerant to flooding even when it is completely submerged at 3.0m depth. This may contribute greatly to the invasiveness of A. philoxeroides and make it very adaptable to habitats that are heavily disturbed (such as by flooding).
|
| [7] |
|
| [8] |
|
| [9] |
Study on weed ecological relationships in autumn-harvested dry crop fields in Jinhua, Zhejiang Province .金华地区秋旱作物田杂草生态相似关系研究 . |
| [10] |
|
| [11] |
The influence of water level and nutrient availability on growth and root system development of https://doi.org/10.1111/j.1365-3180.2008.00667.x URL [本文引用: 1] 摘要
Myriophyllum aquaticum is an aquatic plant of still or slow flowing waters. The species mostly occurs in its emerged growth form in dense stands, but submerged shoots can also be found. Due to its rapid growth, M. aquaticum is considered one of the most important aquatic weeds worldwide. In southern Europe, M. aquaticum occurs in irrigation and drainage systems, rice fields and lowland wetlands. In this study, root development and growth response of M. aquaticum to different water levels and nutrient availabilities were investigated in a rhizotron experiment under Central European climatic conditions. The species shows an ability to respond to drained soil conditions by a rapid root growth (up to >1 cm day鈦宦), resulting in a deep root system under drained conditions. In waterlogged soil, the root system spreads more horizontally. Root density increased with increasing nutrient availability. Root:shoot ratio increased significantly with decreasing nutrient availability. In addition, total shoot length, shoot biomass, root biomass and total biomass differed significantly between different water levels and different nutrient availabilities. Relative growth rate increased with increasing water level and nutrient availability. Shoot porosity was higher in nutrient rich substrate than in nutrient low substrate. Root porosity increased with increasing water level. In conclusion, M. aquaticum shows a high tolerance to different water levels, which may be important for future habitat conditions in waterbodies and wetlands in Central Europe under the impact of global change with increased water level fluctuations.
|
| [12] |
Photosynthetic fluorescence characteristics of five dominant submerged macrophytes in Honghu Lake. 洪湖5种优势沉水植物光合荧光特性比较研究 .https://doi.org/10.7606/j.issn.1000-4025.2015.02.0344 URL 摘要
利用水下饱和脉冲荧光仪（DIVING-PAM）,原位观测洪湖5种优势沉水植物——苦草[Vallisneria natans （Lour.） Hara]、黑藻[Hydrilla verticillata （L.f.） Royle]、狐尾藻（Myriophyllum verticillatum L.）、菹草（Potamogeton crispus L.）和马来眼子菜（Potamogeton wrightii Morong）的量子产量及快速光曲线。结果显示：5种沉水植物苦草、黑藻、狐尾藻、菹草和马来眼子菜最大量子产量（Fv/Fm）分别为0.603、0.723、0.751、0.778和0.646。各物种的开放PSⅡ反应中心原初光能捕获效率（Fv′/Fm′）的大小依次为菹草＞狐尾藻＞黑藻＞马来眼子菜＞苦草,且除黑藻与狐尾藻间差异不显著外,其他物种间差异均显著;各物种光能利用能力（α）的大小依次为菹草＞黑藻＞狐尾藻＞马来眼子菜＞苦草,且除黑藻与狐尾藻间差异不显著外,其他物种间差异均显著;各物种无光抑制的最大潜在相对电子传递速率（rETRm）的大小依次为菹草＞狐尾藻＞黑藻＞马来眼子菜＞苦草,且各物种间差异显著;半饱和光强（Ek）的大小依次为狐尾藻＞菹草＞黑藻＞苦草＞马来眼子菜,且除狐尾藻与菹草间差异不显著外,其他物种间差异均显著。研究表明：洪湖5种优势沉水植物中,菹草和狐尾藻较耐强光,光合速率较高,而苦草则有较强的耐弱光能力。
|
| [13] |
Ecophysiological responses of Jussiaea repens to cadmium exposure. |
| [14] |
New materials of the genus Myriophyllum L. (Haloragaceae) in Taiwan.
A newly recorded species, M. dicoccum, the most commonly cultivated and nearly naturalized species, M. aquaticum, and M. spicatum and M. ussuriense are described. A key to the 4 species of this genus in Taiwan is given.
|
| [15] |
Chlorophylls and carotenoids: Pigments of photosynthetic biomembranes. |
| [16] |
Photosynthetic responses of the riparian plant Arundinella anomala Steud. in Three Gorges reservoir region as affected by simulated flooding. 三峡库区岸生植物野古草(Arundinella anomala Steud.)光合作用对水淹的响应 .
为了阐明水淹对三峡库区岸生植物野古草光合作用的影响，模拟了三峡库区消落带水淹发生情况，考察了在不同水淹处理下野古草(Arundinella anomala Steud.)的光合及叶绿素荧光特性。实验设置了对照 (不进行水淹，常规供水管理)、半淹 (植株置于水中，植株地上部分一半被淹没)、水下0.5m (植株置于水中，植株顶部在水面下0.5m)、水下2m (植株置于水中，植株顶部在水面下2m) 4个不同的水淹深度和0、20、40d和60d等 4个不同的水淹时间处理，测定了在不同水淹深度和水淹时间处理下野古草的净光合速率、总叶绿素含量、PSⅡ的最大光化学效率、电子传递速率、表观量子效率、叶绿素利用效率与羧化效率。结果发现，在水淹前期，水淹对野古草的光合特性影响较小，直到水淹60d后，才对野古草的光合特性产生明显影响，且影响程度随水淹深度的不同而不同。野古草在水淹20d和水淹40d后，各水淹处理的净光合速率与对照相比无明显降低，其中水淹20d后，半淹处理的野古草叶片净光合速率比对照还高出16.1%。水淹60d后，水下0.5m和水下2m的净光合速率显著低于对照和半淹，其净光合速率分别为7.51μmol•m－2•s－1和9.15μmol•m－2•s－1。结果表明，水淹20d和40d对野古草的电子传递速率、表观量子效率和羧化效率没有影响。水淹处理60d后，与对照植株相比，半淹处理植株的电子传递速率、表观量子效率、叶绿素利用效率和羧化效率没有明显变化，但水下0.5m和水下2m处理植株的电子传递速率、表观量子效率、叶绿素利用效率和羧化效率有明显降低。 在整个实验期间，半淹处理植株的净光合速率、电子传递速率、表观量子效率和羧化效率没有受到任何不利影响。尽管在水淹60d后水下0.5m和水下2m处理植株的净光合速率、电子传递速率、表观量子效率、叶绿素利用效率和羧化效率降低，但降低后的数值仍不低于甚至高于一些自然生长的未受水淹的植物物种。研究表明，野古草对水淹具有很好的耐受能力，是一种可以用于三峡库区消落区植被构建的优良植物物种。
|
| [17] |
Potential effects of climate changes on aquatic systems: Laurentian Great Lakes and Precambrian Shield Region. https://doi.org/10.1002/(SICI)1099-1085(19970630)11:83.3.CO;2-7 URL [本文引用: 1] 摘要
The region studied includes the Laurentian Great Lakes and a diversity of smaller glacial lakes, streams and wetlands south of permanent permafrost and towards the southern extent of Wisconsin glaciation. We emphasize lakes and quantitative implications. The region is warmer and wetter than it has been over most of the last 12000 years. Since 1911 observed air temperatures have increased by about 0·11°C per decade in spring and 0·06°C in winter; annual precipitation has increased by about 2·1% per decade. Ice thaw phenologies since the 1850s indicate a late winter warming of about 2·5°C. In future scenarios for a doubled CO2 climate, air temperature increases in summer and winter and precipitation decreases (summer) in western Ontario but increases (winter) in western Ontario, northern Minnesota, Wisconsin and Michigan. Such changes in climate have altered and would further alter hydrological and other physical features of lakes. Warmer climates, i.e. 2 × CO2 climates, would lower net basin water supplies, stream flows and water levels owing to increased evaporation in excess of precipitation. Water levels have been responsive to drought and future scenarios for the Great Lakes simulate levels 0·2 to 2·5 m lower. Human adaptation to such changes is expensive. Warmer climates would decrease the spatial extent of ice cover on the Great Lakes; small lakes, especially to the south, would no longer freeze over every year. Temperature simulations for stratified lakes are 1-7°C warmer for surface waters, and 6°C cooler to 8°C warmer for deep waters. Thermocline depth would change (4 m shallower to 3·5 m deeper) with warmer climates alone; deepening owing to increases in light penetration would occur with reduced input of dissolved organic carbon (DOC) from dryer catchments. Dissolved oxygen would decrease below the thermocline. These physical changes would in turn affect the phytoplankton, zooplankton, benthos and fishes. Annual phytoplankton production may increase but many complex reactions of the phytoplankton community to altered temperatures, thermocline depths, light penetrations and nutrient inputs would be expected. Zooplankton biomass would increase, but, again, many complex interactions are expected.Generally, the thermal habitat for warm-, cool- and even cold-water fishes would increase in size in deep stratified lakes, but would decrease in shallow unstratified lakes and in streams. Less dissolved oxygen below the thermocline of lakes would further degrade stratified lakes for cold water fishes. Growth and production would increase for fishes that are now in thermal environments cooler than their optimum but decrease for those that are at or above their optimum, provided they cannot move to a deeper or headwater thermal refuge. The zoogeographical boundary for fish species could move north by 500-600 km; invasions of warmer water fishes and extirpations of colder water fishes should increase. Aquatic ecosystems across the region do not necessarily exhibit coherent responses to climate changes and variability, even if they are in close proximity. Lakes, wetlands and streams respond differently, as do lakes of different depth or productivity. Differences in hydrology and the position in the hydrological flow system, in terrestrial vegetation and land use, in base climates and in the aquatic biota can all cause different responses. Climate change effects interact strongly with effects of other human-caused stresses such as eutrophication, acid precipitation, toxic chemicals and the spread of exotic organisms. Aquatic ecological systems in the region are sensitive to climate change and variation. Assessments of these potential effects are in an early stage and contain many uncertainties in the models and properties of aquatic ecological systems and of the climate system.
|
| [18] |
Effects of submergence on the growth of Phragmites australis seedlings. |
| [19] |
Biomass allocation in plants: Ontogeny or optimality? A test along three resource gradients. https://doi.org/10.1890/0012-9658(1999)080[2581:BAIPOO]2.0.CO;2 URL [本文引用: 1] 摘要
We examined biomass allocation patterns throughout the entire vegetative growth phase for three species of annual plants along three separate gradients of resource availability to determine whether observed patterns of allocational plasticity are consistent with optimal partitioning theory. Individuals of the annual plant species Abutilon theophrasti, Chenopodium album, and Polygonum pensylvanicum were grown from locally field-gathered seed in controlled greenhouse conditions across gradients of light, nutrients, and water. Frequent harvests were used to determine the growth and allocation (root vs. shoot, and leaf area vs. biomass) responses of these plants over a 57-d period. Growth analysis revealed that each species displayed significant plasticity in growth rates and substantial amounts of ontogenetic drift in root:shoot biomass ratios and ratios of leaf area to biomass across each of the three resource gradients. Ontogenetically controlled comparisons of root:shoot and leaf area ratios across light ...
|
| [20] |
Photosynthetic characteristics of invasive and noninvasive species of Rubus (Rosaceae). https://doi.org/10.3732/ajb.89.9.1431 URL PMID: 21665744 [本文引用: 1] 摘要
The prolific amount of growth and reproduction in invasive plants may be achieved by greater net photosynthesis and/or resource-use efficiency. I tested the hypotheses that leaf-level photosynthetic capacity and resource-use efficiency were greater in two invasive species of Rubus as compared with two noninvasive species that have overlapping distributions in the Pacific Northwest. The invasive species had significantly higher photosynthetic capacity and maintained net photosynthesis (A) over a longer period of the year than the noninvasive species. The construction cost (CC) of leaf tissue per unit leaf mass was comparable among the four species, but the invasive species allocated less nitrogen (N) per unit leaf mass. On a leaf area basis, both leaf CC and N were higher for the invasive species. The specific leaf area (SLA) was also lower in the invasive species, indicating less photosynthetic area per gram leaf tissue. The invasive species achieved high A at lower resource investments than the noninvasive species, including having higher maximum photosynthetic rate (A(max)) per unit dark respiration (R-d), greater A(max) per unit leaf N (photosynthetic nitrogen-use efficiency), and greater water-use efficiency as measured by instantaneous rates of A per unit transpiration (A/E) and by integrated A/E inferred from stable carbon isotope ratios (delta(13)C). Using discriminant analysis, these photosynthetic characteristics were found to be powerful in distinguishing between the invasive and noninvasive Rubus. A(max) and A/E were identified as the most useful variables for distinguishing between the species, and therefore, may be important factors contributing to the success of these invasive species.
|
| [21] |
Underwater photosynthesis in flooded terrestrial plants: A matter of leaf plasticity. |
| [22] |
Cover shift and morphological plasticity of invasive Alternanthera philoxeroides along a riparian zone in South China. Journal of Plant Ecology ( 喜旱莲子草沿河岸带不同生境的盖度变化及形态可塑性 .
喜旱莲子草（Alternanthera philoxeroides）原产南美洲，是中国国家环保总局公布的9种危害最大的外 <BR>来入侵植物之一。该文比较了分布于河岸带4种小生境中，喜旱莲子草和它的同属土著植物莲子草 <BR>（Alternanthera sessilis）的盖度和生长特征变化，以了解影响喜旱莲子草入侵的生境和生长特征。按 <BR>照距水体的距离远近，这些小生境依次为：废弃农田、沼泽、河边沙石滩及河间卵石滩。 结果表明，这4 <BR>种生境在基质性质、土壤养分和生产力方面存在显著的差异。在生产力较高的生境中（如废弃地和沼泽） <BR>，喜旱莲子草是优势种，但在生产力较低的生境中（即河边砾石滩及河间卵石滩）土著种莲子草的相对盖 <BR>度大于喜旱莲子草。随着生境土壤养分的增加，喜旱莲子草表现出明显的形态可塑性。喜旱莲子草与觅光 <BR>相关的几个形态指标，如茎的长度、节间长度和节的 数目以及单叶面积都显著增加；同时，那些着生叶 <BR>片的分枝也从匍匐状转变成直立生长。在生产力较高的生境中，喜旱莲子草的植冠高度和茎干密度成正相 <BR>关，表明喜旱莲子草对极度密集的种群环境有很强的适应能力。这些结果说明，较高的形态可塑性和优先 <BR>占据具有较高土壤养分的小生境是喜旱莲子草沿河岸带入侵的基本特征，可能也是促成其入侵的重要的内<BR>部（植物自身）和外部（生境）条件。
|
| [23] |
Chlorophyll fluorescence as a nonintrusive indicator for rapid assessment of in vivo photosynthesis. https://doi.org/10.1007/978-3-642-79354-7_3 URL [本文引用: 1] 摘要
In the past, ecophysiologically oriented photosynthesis research has been governed by gas-exchange measurements, mainly involving sophisticated (and costly) systems for simultaneous detection of CO 2 uptake and H 2 O evaporation (see, e.g., Field et al. 1989). With the help of these methods, fundamental knowledge on in situ photosynthesis has been gained. Only recently, progress has been made in the development of alternative practical methods for nonintrusive assessment of in vivo photosynthesis which have the potential of not only evaluating overall quantum yield and capacity, but also allowing insights into the biochemical partial reactions and the partitioning of excitation energy (see, e.g., Snel and van Kooten 1990). As a consequence, photosynthesis research at the level of regulatory processes has been greatly stimulated, leading to important new concepts (see reviews by Foyer et al. 1990; Demmig-Adams 1990; Melis 1991; Allen 1992). In particular, chlorophyll fluorescence has evolved as a very useful and informative indicator for photosynthetic electron transport in intact leaves, algae, and isolated chloroplasts (reviews by Briantais et al. 1986; Renger and Schreiber 1986; Schreiber and Bilger 1987, 1992; Krause and Weis 1991; Karukstis 1991).
|
| [24] |
Invasibility of a coastal strip in NE Spain by alien plants. https://doi.org/10.1111/j.1654-1103.2002.tb02085.x URL [本文引用: 1] 摘要
The alien plant species and the ecological factors that facilitate their invasion to a coastal strip in the Baix region (Tarragona, NE Spain) were studied. A detailed inventory of the area showed that 20% of the plant species, most of them from the American Continent, were aliens, many of which were strongly invasive. At the habitat level, the relationships between the invasive and a number of autecological, ecological and habitat variables were analysed by means of logistic analyses. In the best model five variables were related to alien plant invasions: climatic affinity, disturbance of the invaded habitat, route of introduction, soil moisture during summer, and life form. To elucidate the environmental factors that could be responsible for alien plant invasions at a regional scale, the number of alien taxa and the environmental features at 13 localities of the western Mediterranean area were analysed. The warm lowlands, subjected to low annual rainfall and high population density, exhibited the greatest reception capacity for alien . It is concluded that various specific environmental features 鈥 high mean temperatures, the abundance of riparian systems, the existence of biotopes with favourable balance which harbour a great richness of alien species and the high pressure to which the enclave is subjected, combined with the ecological requirements of the alien species and certain species attributes (biotype) can interact at different scales and have caused the over鈥恟epresentation of alien .
|
| [25] |
Effects of epiphyte on the rapid light curves of two submerged macrophytes in Lake Taihu. 附着生物对太湖常见的两种沉水植物快速光曲线的影响 .https://doi.org/10.18307/2010.0618 URL [本文引用: 1] 摘要
在水草生长比较旺盛的季节 (7-8月),以水草较丰富的贡湖湾作为采样区域,野外采样结合室内分析研究太湖常见的两种沉水植物马来眼子菜(Potamogeton malaianus)及穗花狐尾藻(Myriophyllum spicatum)叶上的附着生物的生物量;利用脉冲振幅调制叶绿素荧光仪研究去除附着生物前后两种沉水植物的光合作用的变化.结果表明,马来眼子菜和穗 花狐尾藻两种沉水植物上的附着生物的现存量存在显著的差异,附着生物群落中自养生物与异养生物的比值没有显著差异;两种沉水植物在去除附着生物前后的光合 参数有显著的变化,光合作用效率、半饱和光强、最大电子传递速率增加.这表明附着生物降低了沉水植物光合作用.
|
| [26] |
Morphological plastic responses to water depth and wave exposure in an aquatic plant (Myriophyllum spicatum). |
| [27] |
Anatomy of emersed parrotfeather. |
| [28] |
Plant adaptations to anaerobic stress. https://doi.org/10.1016/j.sna.2009.11.010 URL [本文引用: 2] 摘要
This review first discusses metabolic and morphological adaptations to anaerobic stress (principally caused by soil flooding) in roots, then adaptations in plant shoots, and finally re-integrates activities of both parts of the plant in a section onroot-shoot relationships. Metabolic adaptations in roots to external anaerobic conditions included avoidance of self poisoning and cytoplasmic acidosis, maintenance of adequate supplies of energy and sugar, modifications to gene expression and metabolicacclimatization to tissue anoxia by previous exposure to partial oxygen shortage. Morphological adaptations based on aerenchyma development and internal aeration pathways are emphasized. Shoots are often less susceptible to anaerobic stress than roots.Many wetland species develop tolerance by the rhizomes becoming dormant in anaerobic winter conditions. Escape mechanisms in shoots are based on active and, sometimes, increasingly rapid shoot extension in the presence or absence of oxygen, and formationof replacement roots through adventitious rooting at the shoot base. Root and shoot physiology are integrated by systemic signalling, limiting indirect damage to shoot tissues by soil flooding.
|
| [29] |
|
| [30] |
Environmental risk assessment and management of exotic wetland plants used for treatment of rural domestic sewage. 用于农村生活污水处理的常见外来湿地植物的环境风险评估与管理 .
对用于农村生活污水处理的8种常见外来湿地植物的环境风险进行分析，并利用改良的澳大利亚杂草评估系统和国内的外来物种入侵风险指数评估体系进行综合评价。水葫芦（<em>Eichhornia crassipes</em>）和大薸（<em>Pistia stratiotes</em>）已被界定为入侵植物，风险最大，应该尽量避免使用；粉绿狐尾藻（<em>Myriophyllum aquaticum</em>）和再力花（<em>Thalia dealbata</em>）具有一定的潜在入侵风险，应该慎用；旱伞草（<em>Cyperus alternifolius</em>）、美人蕉（<em>Canna indica</em>）、梭鱼草（<em>Pontederia cordata</em>）和纸莎草（<em>Cyperus papyrus</em>）的风险性相对较低，可以适当地用于人工湿地。利用最大熵（MaxEnt）模型对除水葫芦和大薸以外的上述其他6种外来湿地植物在我国的潜在适生区进行分析的结果表明，这些植物的主要适生区位于我国南方地区。我国南方农村地区分布广泛的稻田、河流、湖库和鱼塘等生态系统极易受到威胁。应加强对人工湿地和湿地植物的管理，从可替代的本土植物、选址、生长管理、隔离和再利用等方面进行管控，降低外来湿地植物的风险，使其更好地应用于农村生活污水的处理，改善农村地区的生态环境。
|
| [31] |
Photosynthetic characteristics of an invasive plant Conyza canadensis and its associated plants. 入侵植物小飞蓬及其伴生植物的光合特性 .
<p>为探讨小飞蓬的入侵机制和制定有效的治理措施，对入侵植物小飞蓬及其主要伴生植物山苦荬和鸭跖草的光合特性进行研究.结果表明: 小飞蓬的光饱和点和光补偿点分别为1634.00和23.84 μmol·m<sup>-2</sup>·s<sup>-1</sup>,介于2种伴生植物之间;光饱和点下的最大净光合速率为28.12 μmol·m<sup>-2</sup>·s<sup>-1</sup>,显著高于２种伴生植物;表观量子效率为0.06,与山苦荬差异不显著,但显著高于鸭跖草.小飞蓬的CO<sub>2</sub>饱和点和CO<sub>2</sub>补偿点分别为834.00和23.69 μmol·mol<sup>-1</sup>;CO<sub>2</sub>饱和点下的最大净光合速率为31.97 μmol·m<sup>-2</sup>·s<sup>-1</sup>,介于2种伴生植物之间;羧化效率为0.078,显著高于伴生植物.有效光合辐射和CO<sub>2</sub>浓度的变化对小飞蓬及其伴生植物的气孔导度、蒸腾速率影响不显著,但显著影响其水分利用率.小飞蓬具有较高的光合速率和物质积累能力,较高的生产力是其成功入侵的重要因素之一.</p>
|
| [32] |
Effects of hydrological characteristics on aquatic plants. 水文特征对水生植物的影响 .
水位、水流等水文特征是影响水生植物的重要因素.水生植物对水位变动的响应主要包括形态特征、生物量、物种分布和物种结构的改变.另一方面,水位变动被认为是一个环境干扰因子,适度的水位变动有利于增加物种多样性;长期的水位变动在植物群落演替上扮演重要的角色.水流不仅能影响水生植物群落结构和物种分布,还能影响其繁殖传播、新陈代谢过程和形态特征.
|
| [33] |
Interpreting phenotypic plasticity: The importance of ontogeny. https://doi.org/10.1046/j.1442-1984.2002.00082.x URL [本文引用: 1] 摘要
First page of article
|
| [34] |
Allelopathic inhibitory effect of Myriophyllum aquaticum (Vell.) Verdc. on Microcystis aeruginosa and its physiological mechanism. 粉绿狐尾藻((Myriophyllum aquaticum)对铜绿微囊藻(Microcystis aeruginosa)的化感抑制效应及其生理机制 .
由于生物法，尤其是水生植物化感控藻方法在治理水体富营养化及水华现象中具有多方面的优势，近年来该领域的理论和技术研究备受世界各国关注。采用初始添加种植水和连续添加种植水的方法，研究挺水型粉绿狐尾藻对铜绿微囊藻的化感抑藻效应，并从光合作用的角度探讨其对铜绿微囊藻化感抑制的生理生态机制及作用靶点。研究结果表明：粉绿狐尾藻能够分泌某些化感物质有效抑制铜绿微囊藻的正常生长，其抑藻效应是通过连续释放某些化感物质作用于铜绿微囊藻而实现的，且具有累积性；粉绿狐尾藻分泌化感物质对铜绿微囊藻的Chl a、PC及APC的损伤程度存在差异（如处理5 d后，Chl a、PC、APC的相对含量分别降至52.7%、15.3%、7.6%），其中藻胆蛋白（尤其是APC）比Chl a 更为敏感，说明藻胆蛋白是粉绿狐尾藻化感物质抑制铜绿微囊藻的关键靶点。研究为水生植物化感控藻技术的发展提供了新的材料，并有助于深入了解水体生态系统的化学生态作用及其机制。
|
| [35] |
Effects of water level fluctuation on the growth of aquatic plants (an experimental ecological study). Master degree dissertation, Wuhan University, Wuhan. (in Chinese with English abstract)水位波动对水生植物生长影响的实验生态学研究 .
研究了湖北梁子湖中几种常见优 势水生植物对水位变化的适应机制，主要结果如下： 1、狐尾藻和微齿眼子菜对水位上升的适应。随水深梯度的增加，狐尾藻分配到根和茎的生物量减少，分配到叶的生物量增加；茎长随水深增加而增长。微齿眼子菜 随水深梯度的增加，分配更多的生物量到茎，而分配到根和叶的生物量减少；茎长呈先增加后降低的趋势。 2、水位波动对微齿眼子菜、苦草、轮叶黑藻和狐尾藻的形态、生长及资源分配的影响。在水位频繁波动下，比茎长都显著降低，根重比除狐尾藻外，在波动情况下 有上升趋势，而其他形态特征(如主茎长、总长和分枝数)及生物量在地上各器官的分配因物种而异。 3、苦草的繁殖策略及应对水位消退后被牧食的机理。苦草鳞茎在梁子湖的垂直分布深度与其大小呈显著正相关；具有不同芽数的鳞茎的重量差异显著。埋藏深度、 水分状况和鳞茎本身的大小都显著影响鳞茎的出土能力。去除第一位芽和切碎鳞茎后促进了其他芽的萌发；去年生未萌发的鳞茎在条件适宜的时候也可以很好的萌 发。这些可能是苦草应对被取食，维持种群数量的有效对策。 4、植物水鳖对水位变化的适应。水鳖漂浮生长时，能够通过根系的变化来适应水位变化，水位上升时，最大根长增加；水位下降时，倾向于扎根生长。扎根生长的 水鳖能够通过叶柄的可塑性来适应水位上涨。
|
| [36] |
An invasive clonal plant benefits from clonal integration more than a co-occurring native plant in nutrient-patchy and competitive environments. https://doi.org/10.1371/journal.pone.0097246 URL PMID: 24816849 [本文引用: 1] 摘要
Many notorious invasive plants are clonal, however, little is known about the different roles of clonal integration effects between invasive and native plants. Here, we hypothesize that clonal integration affect growth, photosynthetic performance, biomass allocation and thus competitive ability of invasive and native clonal plants, and invasive clonal plants benefit from clonal integration more than co-occurring native plants in heterogeneous habitats. To test these hypotheses, two stoloniferous clonal plants, Alternanthera philoxeroides (invasive), Jussiaea repens (native) were studied in China. The apical parts of both species were grown either with or without neighboring vegetation and the basal parts without competitors were in nutrient- rich or -poor habitats, with stolon connections were either severed or kept intact. Competition significantly reduced growth and photosynthetic performance of the apical ramets in both species, but not the biomass of neighboring vegetation. Without competition, clonal integration greatly improved the growth and photosynthetic performance of both species, especially when the basal parts were in nutrient-rich habitats. When grown with neighboring vegetation, growth of J. repens and photosynthetic performance of both species were significantly enhanced by clonal integration with the basal parts in both nutrient-rich and -poor habitats, while growth and relative neighbor effect (RNE) of A. philoxeroides were greatly improved by clonal integration only when the basal parts were in nutrient-rich habitats. Moreover, clonal integration increased A. philoxeroides 's biomass allocation to roots without competition, but decreased it with competition, especially when the basal ramets were in nutrient-rich sections. Effects of clonal integration on biomass allocation of J. repens was similar to that of A. philoxeroides but with less significance. These results supported our hypothesis that invasive clonal plants A. philoxeroides benefits from clonal integration more than co-occurring native J. repens , suggesting that the invasiveness of A. philoxeroides may be closely related to clonal integration in heterogeneous environments.
|
| [37] |
Responses of the threatened aquatic plant Ottelia alismoides to water level fluctuations. https://doi.org/10.1127/1863-9135/2009/0174-0295 URL [本文引用: 6] 摘要
Ottelia alismoides is now at risk of extinction and listed as a threatened aquatic plant species in China. We investigated the responses of O. alismoides to four amplitudes (static, +/- 25, +/- 50 and +/- 75 cm) of water level fluctuations. In all treatments, the water level fluctuated around in initial water depth of 100 cm. Within each amplitude treatment, two fluctuating frequencies were chosen: two cycles (low frequency) and six cycles (high frequency) during the 72 days of the experiment. Leaf characters. (number and area) were not affected by the amplitudes. Below-ground dry weight (DW) allocation was proportionally similar in all treatments. Though there Were no significant differences between the static and fluctuating water levels in the total DW, total DW had a decreasing trend in the +/- 75 cm amplitude. Interestingly, the largest total DW for O. alismoides occurred in the +/- 25 cm amplitude suggesting the species prefers moderately fluctuating water levels. Fruit DW allocation and fruit number were similar in all water regimes, but seed number per fruit decreased in the +/- 75 cm amplitude. O. alismoides generally did not respond to the fluctuating frequencies. We conclude that O. alismoides can tolerate moderate water level fluctuations, but high fluctuating amplitude (+/- 75 cm) reduced the plant performance. Decisions related to conservation of this species should take the disturbance caused by water level fluctuations into consideration.
|
| [38] |
Differential responses of the floating- leaved aquatic plant Nymphoides peltata to gradual versus rapid increases in water levels. https://doi.org/10.1016/j.aquabot.2010.11.004 URL Magsci [本文引用: 2] 摘要
We compared the growth responses of the floating-leaved species Nymphoides peltata to gradual and rapid rising water levels under two nutrient concentrations (1 g and 12 g of slow released fertilizer (N-P-K: 16-8-12) per container filled with 8 kg washed sand), and predicted the population expansion after these floods. The results showed that the capacity for petiole elongation was dependent on leaf age, and only leaves that were no more than five days old had the capability to reach the water surface when the water level increased rapidly from 50 cm to 300 cm. Plants subjected to a gradual rising water level tracked the increase in water depth whose petioles elongated at 3.96 +/- 1.70 cm per day and 4.80 +/- 0.16 cm per day under low and high nutrient concentrations respectively throughout the experiment period. When water levels were rapidly raised, leaf petioles elongated rapidly at 25.48 +/- 1.51 cm per day and 26.64 +/- 2.24 cm per day under low and high nutrient concentrations respectively during the first ten days. Plants under a constant water level maintained highest mean leaf recruitment (mean 3.0 +/- 0.33 leaves and 24.4 +/- 5.87 leaves every ten days under low and high nutrient concentrations, respectively). Therefore, more young leaves existed in the canopy ensuring that when the water level increases, young leaves can rapidly emerge after submergence. Gradual water level rise did not significantly affect biomass and ramet production (4.75 +/- 1.41 g and 5.50 +/- 1.22 ramets in low nutrient: 48.49 +/- 21.45 g and 35.67 +/- 11.78 ramets in high nutrient), but rapid water level rise negatively affected ramet production in both nutrient concentrations (3.00 +/- 1.26 ramets and 11.25 +/- 4.19 ramets in low and high nutrients, respectively). The results indicated that continual leaf recruitment and rapid petiole elongation were both important ways in which N. peltata adapted to increasing water levels. Extreme flooding may be a disturbance factor that affects plant growth and the population expansion of N. peltata, while small gradual water level rise should not harm this species. (C) 2010 Elsevier B.V. All rights reserved.
|
| [39] |
Responses of chlorophyll fluorescence of an invasive plant Spartina alterniflora to continuous waterlogging. 入侵植物互花米草(Spartina alterniflora)叶绿素荧光对淹水胁迫的响应 .
在上海崇明东滩国家级鸟类自然保护区生态修复示范样地中,开展了持续淹水技术治理入侵植物互花米草的物理控制实验.同时,应用叶绿素荧光技术,分别研究了连续2年持续水淹和淹水1年后排水恢复自然生境条件下,外来入侵植物互花米草叶绿素荧光动力学参数及叶绿素含量的动态变化.结果表明,第1年持续淹水降低了互花米草体内的叶绿素含量和PSⅡ最大光化学效率(Fv/Fm)、PSⅡ的潜在活性(Fv/Fo)、光合电子传递速率(ETR)和光化学猝灭(qP)等叶绿素荧光动力参数值,抑制了互花米草的光合作用.随着淹水时间的延长,到第2年生长季节时互花米草已可以通过调节热耗散或其他生理生态指标来适应淹水环境,满足其生长繁殖的需要.一旦解除淹水胁迫,互花米草的光合活性可迅速恢复,甚至超过对照,表现出很强的恢复能力.持续淹水胁迫仅能在初期抑制互花米草的光合作用,随着淹水时间的延长,互花米草可以通过调节其他生理指标来适应淹水环境,保障光合作用的正常进行.
|
| [40] |
The effects of ecophysiological traits on carbon gain in invasive plants. 入侵植物的生理生态特性对碳积累的影响 .
随着国际贸易的发展和人们交往的增加以及全球环境的变化,生物种类在全球扩散的机会也大大增加,从而为生物入侵创造了机会。生物入侵不仅给农林牧生产造成损失,而且具有长期的生态学效应。外来种的成功入侵不是其自身某一个特性决定的,而是其特性与新的生境综合作用的结果。外来入侵种生理生态特性的研究对其预测和防治具有重要的意义。目前对入侵种生理生态特性的研究较少。已有的研究表明,与本地种相比入侵种可能通过提高光合能力、资源利用率、表型可塑性、化感作用,以及降低繁殖成本等增加植株碳积累,促进其入侵。但并不是所有的入侵种都同时具有这些特性。生境不同限制性资源不同,入侵机制就不同。成功的入侵种应该能够高效地利用生境中的限制性资源,并且能够较快地调节自身的生理特性以适应波动的资源环境。
|
| [41] |
Ecological impacts of excessive water level fluctuations in stratified freshwater lakes. https://doi.org/10.5268/IW-1.1.406 URL Magsci [本文引用: 1] 摘要
Water levels of lakes fluctuate naturally in response to climatic and hydrological forcing. Human over-exploitation of water resources leads to increased annual and interannual fluctuations of water levels, at times far beyond natural amplitudes and/or at altered time schedules. Climate change models predict increased occurrence of extreme events (flooding, extended droughts), which will further magnify the seasonal and multiannual amplitude of water level fluctuations in lakes. A relatively wide literature base already exists for shallow lakes, demonstrating that excessive water level fluctuations impair ecosystem functioning, ultimately leading to shifts between clear-water and turbid states. Evidence is gradually building in the published literature demonstrating that deep (stratified) freshwater lakes also respond adversely to excessive water level fluctuations. Analysis of existing data suggests that at moderate disturbance levels littoral habitats are affected, and hence their biota is also impacted. At further disturbance levels, ecosystem destabilization symptoms are observed, including weakening of keystone species, proliferation of nuisance and invasive species, loss of biodiversity, and increased internal nutrient loading. Ultimately, eutrophication symptoms are manifested, especially large and more frequent cyanobacterial blooms, without increased external nutrient loading. Examples from a range of subtropic and temperate freshwater lakes and reservoirs demonstrate that both top-down and bottom-up processes promote those symptoms. The response of aquatic ecosystems, particularly deep lakes, to water level fluctuations is an under-studied field of crucial importance to the management of water resources, where limnologists have a leading role to play in the near future.
|
/
| 〈 |
|
〉 |
