植物生态学报  2015 , 39 (4): 352-361 https://doi.org/10.17521/cjpe.2015.0034

Orginal Article

帽儿山17个种源落叶松针叶的水分利用效率比较

全先奎, 王传宽*

东北林业大学生态研究中心, 哈尔滨 150040

Comparison of foliar water use efficiency among 17 provenances of Larix gmelinii in the Mao’ershan area

QUAN Xian-Kui, WANG Chuan-Kuan*

Center for Ecological Research, Northeast Forestry University, Harbin 150040, China

通讯作者:  * 通讯作者Author for correspondence (E-mail:wangck-cf@nefu.edu.cn)

收稿日期: 2014-11-13

接受日期:  2015-03-17

网络出版日期:  2015-04-01

版权声明:  2015 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:  国家“十二五”科技支撑项目(2011- BAD37B01和中央高校基本科研业务费专项资金资助项目(DL10BA19)

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摘要

研究环境变化下的树木水分利用效率对探讨森林生态系统碳水耦联关系及其对气候变化的响应和适应对策具有重要意义。落叶松(Larix gmelinii)为我国北方森林的建群种之一。将水热条件不同的17个种源落叶松种植在帽儿山森林生态系统研究站的同质园内30年后, 测定其针叶水分利用效率(WUE)及其相关因子。结果表明: WUE、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、比叶面积(SLA)和叶片氮含量(NL)均存在显著的种源差异(p < 0.05)。WUEGs呈显著指数相关关系, 当Gs < 0.2时WUEGs的增大而明显增大, 而当Gs > 0.2时WUE趋于稳定。WUESLANL分别呈线性负相关和正相关关系, 且随种源原地的干燥度指数(AI)的增大其相关性明显增强。WUE和种源原地年平均气温、平均年降水量及AI分别呈线性负相关、负相关和正相关关系, 并且相关系数依次增大; Tr则仅和种源原地年平均气温呈线性正相关关系, 而Pn和种源原地AI呈线性正相关关系。不同种源落叶松由于对种源原地环境条件的适应而存在针叶结构和生理特征的显著差异, 并因此引起针叶水分利用效率的差异。

关键词: 落叶松 ; 水分利用效率 ; 光合生理 ; 干燥度指数 ; 气候变化

Abstract

Aims

Investigating tree water use efficiency (WUE) is important for understanding the coupling of carbon and water cycles in terrestrial ecosystems and its responses and adaptation to climatic change. Dahurian larch (Larix gmelinii), the dominant tree species in the Chinese boreal forest, plays an important role in the regional carbon budget. In this study, we measured the foliar WUE and associated physiological parameters of 30-year-old Dahurian larch trees from 17 provenances with divergent climatic conditions in a common garden. Our specific aims were to compare differences in WUE among the provenances and explore whether the observed differences are attributed to potential adaptation or acclimation to local habitats.

Methods

We have measured net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and leaf nitrogen concentration (NL) of three replicate trees per provenance from mid June to mid September of 2010. WUE was calculated as the ratio of Pn to Tr. Specific leaf area (SLA) was calculated as one-side projected leaf area divided by the leaf dry mass. The aridity index (AI) of each provenance was calculated as the ratio of mean annual evaporation to mean annual precipitation.

Important findings

WUE, Pn, Gs, Tr, SLA and NL all differed significantly among the provenances. WUE showed a significant exponential relationship with Gs. WUE increased significantly with the increase of Gs when the Gs was less than 0.2, and was relatively stable when the Gs was greater than 0.2. WUE was significantly and positively correlated with NL, but negatively with SLA. The degree of these correlations increased with increasing AI values of the tree origins. WUE was negatively correlated with the mean annual temperature and mean annual precipitation of the tree origins, but positively correlated with the AI of the tree origins. Tr and Pn were positively correlated with both mean annual temperature and AI of the tree origins, these results suggest that the trees may adapt to the local climatic conditions of their origins, which results in the significant difference in the needle morphological and physiological properties, and thus WUE among the provenances of Dahurian larch trees.

Keywords: Larix gmelinii ; water use efficiency ; photosynthetic physiology ; aridity index ; climatic change

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全先奎, 王传宽. 帽儿山17个种源落叶松针叶的水分利用效率比较. 植物生态学报, 2015, 39(4): 352-361 https://doi.org/10.17521/cjpe.2015.0034

QUAN Xian-Kui, WANG Chuan-Kuan. Comparison of foliar water use efficiency among 17 provenances of Larix gmelinii in the Mao’ershan area. Chinese Journal of Plant Ecology, 2015, 39(4): 352-361 https://doi.org/10.17521/cjpe.2015.0034

水分利用效率(WUE)是反映植物单位耗水量生产出的同化量的一个重要生理生态参数(Farquhar & Richards, 1984), 是耦合植物叶片光合作用和蒸腾作用的重要指标, 对研究生态系统水循环和碳循环相互作用、揭示植物对全球变化响应和适应对策具有重要意义(Saxe et al., 2001; Gao et al., 2014)。气候变化条件下的树木WUE的响应及其机理已成为全球生态学研究的热点(Monclus et al., 2009; de Miguel et al., 2012; Klein et al., 2013)。温度和降水是影响WUE的两个重要环境因子。有研究认为当温度升高后光合酶活性提高, 气孔导度(Gs)减小, 从而导致WUE增大(Morecroft et al., 1992; Xiao et al., 2013; Xu et al., 2013); 也有研究认为温度升高会导致胞间CO2浓度(Ci)减小、蒸腾速率(Tr)增大, WUE反而减小(Morecroft et al., 1992; Nicotra et al., 2008; Zhu et al., 2011)。降水通过改变土壤水分可利用性和空气湿度, 从而影响树木的气孔关闭和Tr, 进而改变树木的WUE。然而降水和WUE之间关系的研究结果也存在一些不确定性。有研究结果表明二者呈正相关关系(Schulze et al., 1998; Picotte et al., 2007; Niu et al., 2008; Klein et al., 2013); 也有研究认为二者呈负相关关系(Gimenez et al., 1992; Schulze et al., 2006; Monclus et al., 2009; Zhu et al., 2011)。此外, 树种间由于生物学特性的差异导致其对环境的适应方式有所不同, 从而引起WUE种间差异。有研究表明, 相同环境下常绿乔木的WUE大于落叶乔木(Brooks et al., 1997; Kloeppel et al., 1998), 而有些研究却得出相反的结果(Damesin et al., 1997; 渠春梅等, 2001)。因此, 环境变化对树木WUE的影响以及树木WUE对环境变化响应的内在机理还有待于深入研究。

落叶松(Larix gmelinii)作为我国北方森林的主要组成树种, 具有广阔的地理分布范围和多样的生长环境, 其在气候变化条件下的响应及其机理日益受到关注(Wang et al., 2001)。有研究认为, 随着温度和降水变化, 落叶松在我国的分布面积将减小, 甚至北移出境(张新时, 1993; 蒋延玲和周广胜, 2001; 李峰等, 2006)。然而, 多数研究是基于统计模型的预测, 还需实测数据验证。WUE作为反映树木协调碳同化和水分耗散间关系能力的指标, 是树木能否适应变化的环境条件并且生存下去的关键因子。本文研究了同质园内17个种源的30年生树木针叶WUE的种源差异, 探讨这种差异是环境影响下的表型性驯化, 还是基因控制下的遗传适应。这有助于了解和预测气候变化对该树种的影响, 为应对气候变化提供新的依据。我们假设来自于低温和少雨地区的种源具有较高的WUE, 因为较低的温度导致树木具有较高的净光合速率(Pn)和较低的Gs, 单位耗水量生产出更多的同化量; 而降水减少导致空气湿度和土壤含水量降低, 植物叶片比叶面积(SLA)和Gs减小, 蒸腾减弱, 从而WUE增大。

1 材料和方法

1.1 研究概况

本实验所在的同质种植园位于东北林业大学帽儿山森林生态系统研究站内(45.40° N, 127.67° E)。在国内落叶松的自然分布范围内选取代表性种源17个(表1), 于1980年秋采种, 1981年育苗, 1983年春将17个种源的二年实生苗栽种在生态站试验样地内。样地设计按完全随机区组设计, 重复5次, 80株小区设计, 双行排列, 按株行距1.5 m × 2.0 m定植, 四周设有保护行(杨传平等, 2002)。1997年和2001年间伐两次, 株行距现为4.5 m × 2.5 m。该地区气候属于大陆性温带季风气候, 1989-2009年平均年降水量为629 mm, 平均年蒸发量为864 mm, 年平均气温3.1 ℃, 1月和7月份平均气温分别为-18.5 ℃和22 ℃。同质园内土壤、地形、气候条件一致, 平均海拔300 m, 平均坡度10°-15°, 土壤为暗棕色森林土。

表1   落叶松17个种源原地的地理和气候条件

Table 1   The geographic and climatic conditions of the origins of the 17 provenances of Larix gmelinii

种源 Provenance代码
Code
纬度Latitude (N)经度Longitude (E)年平均气温 MAT (℃)平均年降水量
MAP (mm)
平均年蒸发量
MAE (mm)
干燥度
AI
≥10 ℃积温CT (℃)相对湿度 RH (%)
友好 Youhao147.80°128.83°-1.05622.0955.81.542 147.278
乌伊岭 Wuyiling248.67°129.42°-1.19584.61 038.01.781 851.273
新林 Xinlin351.70°124.33°-3.35507.3912.01.801 535.369
桦皮窑 Huapiyao450.70°126.72°-1.50539.01 100.02.041 900.068
三站 Sanzhan549.62°126.80°-1.30527.21 076.02.041 650.070
十八站 Shibazhan652.42°125.27°-2.03480.0999.12.081 680.070
沾河 Zhanhe748.45°126.50°0.12501.71 057.02.112 442.370
塔河 Tahe852.32°124.72°-2.74487.91 028.02.111 671.468
莫尔道嘎 Moerdaoga951.25°120.58°-4.50471.0999.42.121 485.070
甘河 Ganhe1050.58°123.22°-2.50470.01 059.02.251 616.868
根河 Genhe1150.68°121.95°-5.00436.3991.42.271 297.670
鹤北 Hebei1247.55°130.42°1.85530.01 235.02.332 456.074
满归 Mangui1352.05°122.18°-5.83466.01 100.02.361 550.072
绰尔 Chuoer1448.17°121.25°-3.40462.31 122.02.431 238.470
库都尔 Kuerdu1549.78°121.88°-4.00500.01 280.02.561 739.567
阿尔山 Aershan1647.17°119.95°-3.30425.11 100.02.591 354.370
中央站 Zhongyangzhan1750.75°125.20°-2.20484.41 387.02.861 780.069

Meteorological data (1976-1985 average) of original sites were obtained from Yang et al. (2002) and China Meteorological Administration. AI, aridity index; CT, cumulative temperature above 10 °C; MAE, mean annual evaporation; MAP, mean annual precipitation; MAT, mean annual temperature; RH, relative humility.气象数据(1976-1985)来自杨传平等(2002)和国家气象局资料。

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1.2 光合测定

每个种源选取3株标准木作为研究对象, 每株标准木选取冠层上部向阳的当年生枝新生针叶3簇进行测定。在2010年生长季内的6月、8月和9月中旬, 选择晴朗天气于6:30-12:00, 采用LI-6400便携式CO2/H2O红外分析仪(LI-COR, Lincoln, USA)离体测定针叶气体交换过程以及相应的环境因子。测定时设定的叶室环境为: 温度25 ℃, 外界空气进入叶室的流速500 μmol·s-1, CO2浓度400 μmol CO2·mol-1。测定时先采用饱和光强对叶片进行充分光诱导, 当光合速率稳定后开始测定, 测定输出参数包括Pn (μmol CO2·m-2·s-1)、Tr (mmol H2O·m-2·s-1)、Gs (mol H2O·m-2·s-1)等。用于光合测定的针叶面积采用扫描图像处理获得, 随后将叶片在65 ℃下烘干至恒质量(精度0.0001 g), 获取其SLA (cm2·g-1):

SLA = 叶面积/叶干质量 (1)

叶片尺度的WUE (μmol CO2·mmol-1 H2O)由下式获得:

WUE = Pn/Tr (2)

干燥度指数(aridity index, AI)由下式获得:

AI = MAE/MAP (3)

式中, MAE为各种源树木种子来源地(种源原地)的平均年蒸发量(mm); MAP为种源原地平均年降水量(mm)。

1.3 养分测定

测定光合的同时摘取与光合测定针叶相同位置的当年生枝新生针叶100 g (鲜质量), 放于4 ℃冷藏箱保存后带回实验室分析。在实验室内, 将样品置于65 ℃烘箱中烘至恒重(精度0.0001 g), 然用将样品粉碎、过筛、装袋, 用于元素含量测定。叶片氮含量(NL)采用全自动凯氏定氮仪(Kjeltec 8400, Foss, Hillerød, Danmark)测定。

1.4 数据分析

以每株标准木为统计单位, 3株标准木的平均值代表一个种源整体水平。通过单因素方差分析比较叶片PnTrWUEGsSLANL的种源差异。应用SPSS 13.0统计软件对数据进行相关分析和方差分析, 并用Ducan法进行多重比较, 方差分析前对所有数据进行方差齐性检验和正态分布检验。

2 结果

2.1 WUE及其相关因子的种源差异

落叶松针叶的PnTrWUEGsSLANL均存在显著的种源差异(p < 0.05, 图1)。种源间PnGsWUE均变异较大, 波动范围分别为(8.6 ± 0.11) - (13.79 ± 0.48) μmol CO2·m-2·s-1、(0.15 ± 0.001) - (0.25 ± 0.01) mol H2O·m-2·s-1和(2.88 ± 0.10) -(4.35 ± 0.15) μmol CO2·mmol-1 H2O; 而TrSLANL则具有较小的变异, 变动范围分别为(2.31 ± 0.08) - (3.36 ± 0.23) mmol H2O·m-2·s-1、(108.5 ± 2.85) -(135.13 ± 8.11) cm2·g-1、(17.25 ± 0.16) - (20.19 ± 0.26) mg·g-1。总体平均值分别为(10.74 ± 0.42) μmol CO2·m-2·s-1 (Pn)、(2.87 ± 0.07) mmol H2O·m-2·s-1 (Tr)、(3.61 ± 0.11) μmol CO2·mmol-1 H2O (WUE)、(0.20 ± 0.007) mol H2O·m-2·s-1 (Gs)、(119.95 ± 1.90) cm2·g-1 (SLA)和(18.84 ± 0.18) mg·g-1 (NL)。

图1   落叶松针叶净光合速率(Pn)、蒸腾速率(Tr)、水分利用效率(WUE)、气孔导度(Gs)、比叶面积(SLA)和叶氮含量(NL)的种源比较(平均值±标准误差, n = 9)。不同字母表示种源间差异显著(p < 0.05)。种源代码同表1

Fig. 1   Comparisons of foliar net photosynthetic rate (Pn), transpiration rate (Tr), water use efficiency (WUE), stomatal conductance (Gs), special leaf area (SLA), and leaf nitrogen concentration (NL) of Larix gmelinii trees originating from 17 provenances (mean ± SE, n = 9). Different letters indicate significant differences among provenances (p < 0.05). Provenance codes see Table 1.

2.2 WUE与叶结构特征之间的关系

WUESLAGs以及NL均显著相关, 而相关趋势随着种源原地AI的不同有所差异(p < 0.01, 图2)。WUEGs呈显著指数相关关系: 在Gs < 0.2范围内WUEGs的增大而明显增大, 而当Gs > 0.2时WUE则趋于稳定。WUESLANL分别呈显著负线性相关和正相关关系(p < 0.01, 图2), 且随着种源原地AI的增大其相关性明显增强, 其相关斜率分别为-0.0214和0.3180 (AI > 2.4)、-0.0189和0.2134 (2.1 < AI < 2.4)、-0.0151和0.1974 (AI < 2.1) (图2)。

图2   不同干燥度指数(AI)范围内落叶松针叶水分利用效率(WUE)和气孔导度(Gs)、比叶面积(SLA)、叶氮含量(NL)间关系。

Fig. 2   Relationships between foliar water use efficiency (WUE) and stomatal conductance (Gs), special leaf area (SLA), and leaf nitrogen concentration (NL) for the Larix gmelinii trees within different groups of the aridity index (AI).

2.3 WUE与种源原地气候因子的关系

WUE、PnTr和种源原地年气候特征间存在明显相关关系, 而相关趋势和程度因气候因子的不同而有所差异(图3)。WUE和种源原地年平均气温、平均年降水量及AI分别呈线性负相关、负相关和正相关关系, 并且相关系数依次增大, 分别为0.34、0.48和0.85 (p < 0.05, 图3G-3I); Tr则仅和种源原地年平均气温呈线性正相关关系(p < 0.05, 图3D), 且在不同蒸发量范围内和种源原地AI呈线性负相关关系(图3E), 而Pn和种源原地AI呈线性正相关关系(p < 0.001, 图3C), 并且在不同的降水范围内和种源原地年平均气温呈线性正相关关系(p < 0.05, 图3A)。

图3   落叶松针叶净光合速率(Pn)、蒸腾速率(Tr)及水分利用效率(WUE)与种源原地年平均气温(MAT)、平均年降水量(MAP)及干燥度指数(AI)关系。

Fig. 3   Foliar water use efficiency (WUE), transpiration rate (Tr), and net photosynthetic rate (Pn) for 17 Larix gmelinii provenances in relation to mean annual temperature (MAT), mean annual precipitation (MAP) and aridity index (AI) of the origins.

3 讨论

3.1 影响WUE的生物因子

作为WUE的两大组分, Pn的增大或Tr的减小都会导致WUE的增大。本研究中落叶松叶片Pn存在显著的种源差异, 并且与种源原地的AI有显著的正相关性(表1; 图1, 图3), 这和以往对来自不同纬度种源树木研究结果相似(Soolanayakanahally et al., 2009; Robson et al., 2012)。较高的叶Gs、氮含量和较小的SLA导致了较高的Pn, 并且Pn和种源原地的气候条件具有明显的相关关系, 这是基因调控下的Pn对种源原地环境长期适应的结果(Martin et al., 2007; Savolainen et al., 2007; Soolanayakanahally et al., 2009; Frei et al., 2012)。除友好种源外, 随着Pn的增大, WUE表现出相近的变化趋势; 虽然叶片Tr也存在显著的种源差异, 然而WUE并没有随着Tr的变化表现出相应的变化趋势(图1), 这表明WUEPn的影响较大。从研究结果变异程度而言, Pn的变异系数为15.95%, 最高值是最低值的1.60倍, 而Tr的变异系数为9.6%, 最高值较最低值高出44.99%, 由此使得WUE的变异趋势和Pn相近。这是因为叶片的其他生理和结构特征, 如叶片的GsNLSLA等直接影响PnTr, 进而引起了WUE的差异(Gago et al., 2014)。

Gs作为叶片同外界进行水分和气体交换的主要通道, 调节着碳同化速率和水分消耗间的平衡(Gagen et al., 2011)。在一定范围内, 当Gs升高时叶片Ci增加, 导致Pn增大, 虽然Tr也增大, 但光合速率增大的幅度较大, 从而GsWUE呈一定的正相关关系(Picotte et al., 2007; Gago et al., 2014), 但随着Gs的继续增大, 叶片在通过气孔得到CO2和失去水分间达到平衡, 此时WUE的限制因素不再是Gs, 而转为光合相关的酶含量和活性等其他生理因素(Farquhar et al., 1989; Gimenez et al., 1992)。本试验结果表明在起始阶段WUEGs呈明显线性相关, 而当Gs增大到0.2左右时WUE趋于稳定, 但来自于较干旱地方的种源树木在相同WUE水平时需要较低的Gs (图2A), 这验证了我们假设干旱条件下树木通过减小Gs提高WUE的假设。通过较小的Gs获得较大的WUE可以使树木在干旱的条件下减少水分的蒸腾损失, 调节树木水势变化, 避免脱水, 从而提高植物对土壤水分的有效利用(Kenney et al., 2014)。来自不同水分条件地区种源树木在同质园内生长30年后, 还存有与原地气候相适应的GsWUE的凋节方式, 这表现出明显的子代遗传效应。de Miguel等(2012)通过对来自全胞家系海岸松(Pinus pinaster)无性系苗木的研究也取得了相似的结果。

SLA作为叶片结构的重要特征之一也是影响WUE的重要因素, 有研究表明随着SLA的减小, 叶片厚度增加、光合组织密度增大, 导致水分的蒸腾减小和固碳能力提高, 从而WUE增大, 因此两者间多表现为负相关关系(Reich et al., 1998; Lamont et al., 2002; Warren et al., 2005; Gago et al., 2014)。目前对于两者间关系的研究多集中在树种间(Lamont et al., 2002; Holtum & Winter, 2005)、同一树种不同种源幼苗间(Fernández et al., 1999; Warren et al., 2005)、同一种源不同幼苗个体间(Monclus et al., 2009; Roussel et al., 2009; de Miguel et al., 2012)等方面的表型差异, 而对环境变化下两者间的关系及其调控机理研究较少。de Miguel等(2012)对全同胞家系海岸松幼苗研究发现SLAWUE存在负相关关系, 并认为这是基因调控的结果并能通过子代遗传, 相似的结果在其他研究中也有所体现(Fernández et al., 1999; Ramírez-Valiente et al., 2011)。和我们假设相一致的是, 17个种源落叶松的30年树木SLA具有明显的种源差异并和WUE间存在显著的负相关关系(p < 0.05), 且随着种源原地AI的增大SLAWUE的影响程度增强(图2B)。这种在同质环境中生活多年仍存在显著的种源间差异且和种源原地气候条件有较好关系的结果进一步支持了这种差异是一种基因调控下的对种源原地环境长期适应的结果。

本研究结果表明落叶松NLWUE间存在显著的正相关关系, 并且来自于高AI地区的种源树木WUENL具有更高的敏感性(图2C)。有研究表明: 来自低温少雨地区种源的树木具有较高的NL, 以此提高光合能力获取更多的光合产物, 从而适应低温干燥的环境并且从贫瘠的土壤中获取更多的养分和水分(Reich et al., 1996; Weih & Karlsson, 2001; Oleksyn et al., 2003; Tjoelker et al., 2008; Bresson et al., 2011)。因此, 树木NLWUE间多表现为正相关关系(Sparks & Ehleringer, 1997; Monclus et al., 2009; Yan et al., 2014)。相同NL水平下来自于高AI种源树木具有更高的WUE, 这对该树种能够在多样的环境中生存具有重要的现实意义。这是因为在干旱贫瘠的环境中土壤氮和水是树木生长的限制因子, 通过提高叶片氮的利用效率获得更多的光合产物、提高WUE, 从而有助于其生长和生存(Kenney et al., 2014; Yan et al., 2014)。此外, 在模拟未来气候变化对树木生长乃至生存的影响时, 研究者认为气候的变化将导致落叶松分布区内永冻层融解萎缩, 土壤干燥, 湿润度下降, 最终使得落叶松林不适应新环境而逐步北移, 直至出境(张新时, 1993; 蒋延玲和周广胜, 2001; 李峰等, 2006)。本研究发现落叶松树木可以通过调节叶片结构、养分含量、光合生理等形态和生理特征来调节WUE而适应干旱的环境, 这对研究该树种在气候变化下的应对策略和对新环境的适应能力具有重要的参考价值。

3.2 影响WUE的环境因子

树木在长期的进化和选择过程中已形成通过改变生理、分子以及遗传等方面特征去响应环境改变的能力, 然而在目前全球气候变化加剧的背景下, 树木能否通过这种能力的改变去适应未来快速的气候变化已成为研究的热点问题(Saxe et al., 2001; Allen et al., 2010; Kremer et al., 2012; Shaw & Etterson, 2012; Reyer et al., 2013)。研究同质种植园内同一树种不同种源树木的差异及其和种源原地气候条件的关系是一种验证树木对气候适应/驯化的重要方法(Reich et al., 1996; Warren et al., 2005; Martin et al., 2007; Frei et al., 2012)。

与本文假设相同的是, 来自于低温少雨地区的种源具有较高的WUE, 并且和种源原地年平均气温及平均年降水量均呈线性负相关关系(图3G、3H)。这是因为随着温度的升高叶片光合作用酶的活性增强、Gs增大, 进而影响CO2同化速率和Tr, 导致WUE的差异。本研究中17个种源落叶松的PnTr均存在显著的种间差异, 但随着种源原地温度的升高, Tr明显增大, 而Pn总体上并没有表现出明显的增大趋势, 仅在一定的降水区间内和温度存在一定的线性相关(图3A、3D)。因此, 本研究中树木Tr的增大是导致WUE和种源原地年平均气温负相关的主要原因。温度和树木WUE间这种负相关性在相近的研究中也有所体现(Morecroft et al., 1992; Nicotra et al., 2008; Zhu et al., 2011)。大量种源试验表明树木在干旱环境条件下具有更高的WUE (Anderson et al., 2000; Warren & Adams, 2000; Gouveia & Freitas, 2009; Ran et al., 2013), 这是由于干旱环境下空气湿度和土壤含水量降低、叶片GsTr减小, 而Pn的变化相对较小, 从而导致WUE增大(Farquhar et al., 1989; Zhu et al., 2011; Liu et al., 2013)。然而, 本研究结果显示PnTr均与种源原地平均年降水量不相关(图3B、3E), 这是因为降水只考虑了水分收入, 未考虑水分的支出等情况, 不能完全表征一个地方的干旱程度。Warren等(2005)对同质园内来自于水分条件差异明显的15个种源Eucalyptus sideroxylon树木研究表明叶片WUE存在种源差异, 但和降水没有明显相关性, 相似的结果也在对不同种源Eucalyptus microtheca的研究中出现(Li, 2000)。因此选用一个较合理的代表气候干旱程度的指标尤为重要, AI作为表征一个地区干湿程度的指标, 近来成为全球变化研究中经常涉及的气候指标之一(Arora, 2002; 孟猛等, 2004)。本研究结果表明落叶松针叶WUEAI显著正相关且相关性高于降水和温度(图3), 这与Warren和Adams (2000)对海岸松4个种源树木的研究结果相一致。此外, AIPn也存在线性正相关关系, 并且和不同水分蒸发范围内的Tr存在显著相关关系。这表明干旱情况下Pn的增加和Tr的减小是WUE提高的主要原因(Ramírez-Valiente et al., 2011)。

4 结论

来自17个种源地的落叶松树木, 经过在同质园内30多年的生长, 其PnTrGsSLANL均存在显著的种源差异, 从而引起其水分利用效率发生相应的变化。随着种源原地AI的增大, GsSLANLWUE间相关性增强。WUE和种源原地的年平均气温、平均年降水量均呈线性负相关关系, 而和年平均干燥度呈线性正相关关系, 并且相关性依次增大。这表明落叶松为了适应种源原地的环境条件, 在叶的形态特征和光合生理功能上产生具有遗传能力的变异, 从而能够在多样的环境条件下生存和繁衍。

致谢 感谢黑龙江帽儿山森林生态系统国家野外科学观测研究站和林木遗传育种国家重点实验室(东北林业大学)提供的野外基础支持。

作者声明没有竞争性利益冲突.


参考文献

[1] Allen CD, Macalady AK, Chenchouni H, Bachelet D, McDowell N, Vennetier M, Kitzberger T, Rigling A, Breshears DD, Hogg E, Gonzalez P, Fensham R, Zhang Z, Castro J, Demidova N, Lim JH, Allard G, Running SW, Semerci A, Cobb N (2010).

A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests.

Forest Ecology and Management, 259, 660-684.

[本文引用: 1]     

[2] Anderson JE, Kriedemann PE, Austin MP, Farquhar GD (2000).

Eucalypts forming a canopy functional type in dry sclerophyll forests respond differentially to environment.

Australian Journal of Botany, 48, 759-775.

[本文引用: 1]     

[3] Arora VK (2002).

The use of the aridity index to assess climate change effect on annual runoff.

Journal of Hydrology, 265, 164-177.

[本文引用: 1]     

[4] Bresson CC, Vitasse Y, Kremer A, Delzon S (2011).

To what extent is altitudinal variation of functional traits driven by genetic adaptation in european oak and beech?

Tree Physiology, 31, 1164-1174.

[本文引用: 1]     

[5] Brooks JR, Flanagan JR, Buchmann N, Ehleringer JR (1997).

Carbon isotope composition of boreal plants: Functional grouping of life forms.

Oecologia, 110, 301-311.

[本文引用: 1]     

[6] Damesin C, Rambal S, Joffre R (1997).

Between-tree variations in leaf δ13C of Quercus pubescens and Quercus ilex among Mediterranean habitats with different water availability.

Oecologia, 111, 26-35.

[本文引用: 1]     

[7] de Miguel M, Sánchez-Gómez D, Cervera MT, Aranda I (2012).

Functional and genetic characterization of gas exchange and intrinsic water use efficiency in a full-sib family of Pinus pinaster Ait. in response to drought.

Tree Physiology, 32, 94-103.

[本文引用: 2]     

[8] Farquhar GD, Ehleringer JR, Hubick KT (1989).

Carbon isotope discrimination and photosynthesis.

Annual Review of Plant Biology, 40, 503-537.

[本文引用: 2]     

[9] Farquhar GD, Richards RA (1984).

Isotopic composition of plant carbon correlates with water-use efficiency of wheat genotypes.

Australian Journal of Plant Physiology, 11, 539-552.

[本文引用: 1]     

[10] Fernández M, Gil L, Pardos JA (1999).

Response of Pinus pinaster Ait. provenances at early age to water supply. I. Water relation parameters.

Annals of Forest Science, 56, 179-187.

[本文引用: 2]     

[11] Frei ES, Scheepens JF, Armbruster GFJ, Stöcklin J (2012).

Phenotypic differentiation in a common garden reflects the phylogeography of a widespread alpine plant.

Journal of Ecology, 100, 297-308.

[本文引用: 2]     

[12] Gagen M, Finsinger W, Wagner-Cremer F, McCarroll D, Loader NJ, Robertson I, Jalkanen R, Young G, Kirchhefer A (2011).

Evidence of changing intrinsic water-use efficiency under rising atmospheric CO2 concentrations in boreal fennoscandia from subfossil leaves and tree ring δ13C ratios.

Global Change Biology, 17, 1064-1072.

[本文引用: 1]     

[13] Gago J, Douthe C, Florez-Sarasa I, Escalona JM, Galmes J, Fernie AR, Flexas J, Medrano H (2014).

Opportunities for improving leaf water use efficiency under climate change conditions.

Plant Science, 226, 108-119.

[本文引用: 3]     

[14] Gao Y, Zhu XJ, Yu GR, He NP, Wang QF, Tian J (2014).

Water use efficiency threshold for terrestrial ecosystem carbon sequestration in China under afforestation.

Agricultural and Forest Meteorology, 195-196, 32-37.

[本文引用: 1]     

[15] Gimenez C, Mitchell VJ, Lawlor DW (1992).

Regulation of photosynthetic rate of two sunflower hybrids under water stress.

Plant Physiology, 98, 516-524.

[本文引用: 2]     

[16] Gouveia AC, Freitas H (2009).

Modulation of leaf attributes and water use efficiency in quercus suber along a rainfall gradient.

Trees, 23, 267-275.

[本文引用: 1]     

[17] Holtum JAM, Winter K (2005).

Carbon isotope composition of canopy leaves in a tropical forest in panama throughout a seasonal cycle.

Trees, 19, 545-551.

[本文引用: 1]     

[18] Jiang YL, Zhou GS (2001).

Carbon equilibrium in Larix gmelinii forest and impact of global change on it.

Chinese Journal of Applied Ecology, 12, 481-484.(in Chinese with English abstract)

[本文引用: 2]     

[蒋延玲, 周广胜 (2001).

兴安落叶松林碳平衡和全球变化影响研究

. 应用生态学报, 12, 481-484.]

[本文引用: 2]     

[19] Kenney AM, McKay JK, Richards JH, Juenger TE (2014).

Direct and indirect selection on flowering time, water-use efficiency (WUE, δ13C), and WUE plasticity to drought in Arabidopsis thaliana.

Ecology and Evolution, 4, 4505-4521.

[本文引用: 2]     

[20] Klein T, Di Matteo G, Rotenberg E, Cohen S, Yakir D (2013).

Differential ecophysiological response of a major mediterranean pine species across a climatic gradient.

Tree Physiology, 33, 26-36.

[本文引用: 2]     

[21] Kloeppel BD, Gower ST, Treichel IW, Kharuk S (1998).

Foliar carbon isotope discrimination in Larix species and sympatric evergreen conifers: A global comparison.

Oecologia, 114, 153-159.

[本文引用: 1]     

[22] Kremer A, Ronce O, Robled-Arnuncio JJ, Guillaume F, Bohrer G, Nathan R, Bridle JR, Gomulkiewicz R, Klein EK, Ritland K, Kuparinen A, Gerber S, Schueler S (2012).

Long-distance gene flow and adaptation of forest trees to rapid climate change.

Ecology Letters, 15, 378-392.

[本文引用: 1]     

[23] Lamont BB, Groom PK, Cowling RM (2002).

High leaf mass per area of related species assemblages may reflect low rainfall and carbon isotope discrimination rather than low phosphorus and nitrogen concentrations.

Functional Ecology, 16, 403-412.

[本文引用: 2]     

[24] Li CY (2000).

Population differences in water-use efficiency of Eucalyptus microtheca seedlings under different watering regimes.

Physiologia Plantarum, 108, 134-139.

[本文引用: 1]     

[25] Li F, Zhou GS, Cao MC (2006).

Responses of Larix gmelinii geographical distribution to future climate change: A simulation study.

Chinese Journal of Applied Ecology, 17, 2255-2260.(in Chinese with English abstract)

[本文引用: 2]     

[李峰, 周广胜, 曹铭昌 (2006).

兴安落叶松地理分布对气候变化响应的模拟

. 应用生态学报, 17, 2255-2260.]

[本文引用: 2]     

[26] Liu XP, Fan YY, Long JX, Wei RF, Kjelgren R, Gong CM, Zhao J (2013).

Effects of soil water and nitrogen availability on photosynthesis and water use efficiency of Robinia pseudoacacia seedlings.

Journal of Environmental Sciences, 25, 585-595.

[本文引用: 1]     

[27] Martin RE, Asner GP, Sack L (2007).

Genetic variation in leaf pigment, optical and photosynthetic function among diverse phenotypes of Metrosideros polymorpha grown in a common garden.

Oecologia,151, 387-400.

[本文引用: 2]     

[28] Meng M, Ni J, Zhang ZG (2004).

Aridity index and its applications in geo-ecological study.

Acta Phytoecologica Sinica, 28, 853-861.(in Chinese with English abstract)

[本文引用: 1]     

[孟猛, 倪健, 张治国 (2004).

地理生态学的干燥度指数及其应用评述

. 植物生态学报, 28, 853-861.]

[本文引用: 1]     

[29] Monclus R, Villar M, Barbaroux C, Bastien C, Fichot R, Delmotte FM, Delay D, Petit JM, Bréchet C, Dreyer E, Brignolas F (2009).

Productivity, water-use efficiency and tolerance to moderate water deficit correlate in 33 poplar genotypes from a Populus deltoides × Populus trichocarpa F1 progeny.

Tree Physiology, 29, 1329-1339.

[本文引用: 4]     

[30] Morecroft MD, Woodward FI, Marris RH (1992).

Altitudinal trends in leaf nutrient contents, leaf size and δ13C of Alchemilla alpina.

Functional Ecology, 6, 730-740.

[本文引用: 3]     

[31] Nicotra AB, Cosgrove MJ, Cowling A, Schlichting CD, Jones CS (2008).

Leaf shape linked to photosynthetic rates and temperature optima in South African Pelargonium species.

Oecologia, 154, 625-635.

[本文引用: 2]     

[32] Niu SL, Wu MY, Han Y, Xia JY, Li LH, Wan SQ (2008).

Water-mediated responses of ecosystem carbon fluxes to climatic change in a temperate steppe.

New Phytologist, 177, 209-219.

[本文引用: 1]     

[33] Oleksyn J, Reich PB, Zytkowiak R, Karolewski P, Tjoelker MG (2003).

Nutrient conservation increases with latitude of origin in european Pinus sylvestris populations.

Oecologia, 136, 220-235.

[本文引用: 1]     

[34] Picotte JJ, Rosenthal DM, Rhode JM, Cruzan MB (2007).

Plastic responses to temporal variation in moisture availability: Consequences for water use efficiency and plant performance.

Oecologia, 153, 821-832.

[本文引用: 2]     

[35] Qu CM, Han XG, Su B, Huang JH, Jiang GM (2011).

The characteristics of foliar δ13C values of plants and plant water use efficiency indicated by δ13C values in two fragmented rain forests in Xishuangbanna, Yunnan.

Acta Botanica Sinica, 43, 186-192.(in Chinese with English abstract)

[本文引用: 1]     

[渠春梅, 韩兴国, 苏波, 黄建辉, 蒋高明 (2001).

云南西双版纳片断化热带雨林植物叶片δ13C值的特点及其对水分利用效率的指示

. 植物学报, 43, 186-192.]

[本文引用: 1]     

[36] Ramírez-Valiente JA, Valladares F, Huertas AD, Granados S, Aranda I (2011).

Factors affecting cork oak growth under dry conditions: Local adaptation and contrasting additive genetic variance within populations.

Tree Genetics & Genomes, 7, 285-295.

[本文引用: 2]     

[37] Ran F, Zhang XL, Zhang YB, Korpelainen H, Li CY (2013).

Altitudinal variation in growth, photosynthetic capacity and water use efficiency of Abies faxoniana Rehd. et Wils. seedlings as revealed by reciprocal transplantations.

Trees, 27, 1405-1416.

[本文引用: 1]     

[38] Reich P, Oleksyn J, Tjoelker M (1996).

Needle respiration and nitrogen concentration in scots pine populations from a broad latitudinal range: A common garden test with field-grown trees.

Functional Ecology, 10, 768-776.

[本文引用: 2]     

[39] Reich PB, Walters MB, Tjoelker MG, Vanderklein D, Buschena C (1998).

Photosynthesis and respiration rates depend on leaf and root morphology and nitrogen concentration in nine boreal tree species differing in relative growth rate.

Functional Ecology, 12, 395-405.

[本文引用: 1]     

[40] Reyer CPO, Leuzinger S, Rammig A, Wolf A, Bartholomeus RP, Bonfante A, de Lorenzi F, Dury M, Gloning P, Abou Jaoudé R, Klein T, Kuster TM, Martins M, Niedrist G, Riccardi M, Wohlfahrt G, de Angelis P, de Dato G, François L, Menze A, Pereira M (2013).

A plant’s perspective of extremes: Terrestrial plant responses to changing climatic variability.

Global Change Biology, 19, 75-89.

[本文引用: 1]     

[41] Robson TM, Sánchez-Gómez D, Cano FJ, Aranda I (2012).

Variation in functional leaf traits among beech provenances during a spanish summer reflects the differences in their origin.

Tree Genetics & Genomes, 8, 1111-1121.

[本文引用: 1]     

[42] Roussel M, Le Thiec D, Montpied P, Ningre N, Guehl JM, Brendel O (2009).

Diversity of water use efficiency among Quercus robur genotypes: Contribution of related leaf traits.

Annals of Forest Science, 66, 408.

[本文引用: 1]     

[43] Savolainen O, Pyhäjärvi T, Knürr T (2007).

Gene flow and local adaptation in trees.

Annual Review of Ecology, Evolution, and Systematics, 38, 595-619.

[本文引用: 1]     

[44] Saxe H, Cannell MGR, Johnsen Ø, Ryan MG, Vourlitis G (2001).

Tree and forest functioning in response to global warming.

New Phytologist, 149, 369-399.

[本文引用: 2]     

[45] Schulze ED, Turner NC, Nicolle D, Schumacher J (2006).

Leaf and wood carbon isotope ratios, specific leaf areas and wood growth of Eucalyptus species across a rainfall gradient in Australia.

Tree Physiology, 26, 479-492.

[本文引用: 1]     

[46] Schulze ED, Williams RJ, Farquhar GD, Schulze W, Langridge J, Miller JN, Walker BH (1998).

Carbon and nitrogen isotope discrimination and nitrogen nutrition of trees along a rainfall gradient in northern Australia.

Australian Journal of Plant Physiology, 25, 413-425.

[本文引用: 1]     

[47] Shaw RG, Etterson JR (2012).

Rapid climate change and the rate of adaptation: Insight from experimental quantitative genetics.

New Phytologist, 195, 752-765.

[本文引用: 1]     

[48] Soolanayakanahally RY, Guy RD, Silim SN, Drewes EC, Schroeder WR (2009).

Enhanced assimilation rate and water use efficiency with latitude through increased photosynthetic capacity and internal conductance in balsam poplar (Populus balsamifera L.).

Plant, Cell & Environment, 32, 1821-1832.

[本文引用: 2]     

[49] Sparks JP, Ehleringer JR (1997).

Leaf carbon isotope discrimination and nitrogen content for riparian trees along elevational transects.

Oecologia, 109, 362-367.

[本文引用: 1]     

[50] Tjoelker MG, Oleksyn J, Reich PB, Żytkowiak R (2008).

Coupling of respiration, nitrogen, and sugars underlies convergent temperature acclimation in Pinus banksiana across wide-ranging sites and populations.

Global Change Biology, 14, 782-797.

[本文引用: 1]     

[51] Wang C, Gower ST, Wang Y, Zhao H, Yan P, Bond-Lamberty BP (2001).

The influence of fire on carbon distribution and net primary production of boreal Larix gmelinii forests in Northeastern China.

Global Change Biology, 7, 719-730.

[本文引用: 1]     

[52] Warren CR, Adams MA (2000).

Water availability and branch length determine δ13C in foliage of Pinus pinaster.

Tree Physiology, 20, 637-643.

[本文引用: 1]     

[53] Warren CR, Tausz M, Adams MA (2005).

Does rainfall explain variation in leaf morphology and physiology among populations of red ironbark (Eucalyptus sideroxylon subsp. tricarpa) grown in a common garden?

Tree Physiology, 25, 1369-1378.

[本文引用: 3]     

[54] Weih M, Karlsson PS (2001).

Growth response of mountain birch to air and soil temperature: Is increasing leaf- nitrogen content an acclimation to lower air temperature?

New Phytologist, 150, 147-155.

[本文引用: 1]     

[55] Xiao JF, Sun G, Chen JQ, Chen H, Chen SP, Dong G, Gao SH, Guo HQ, Guo JX, Han SJ, Kato T, Li YL, Lin GH, Lu WZ, Ma MG, McNulty S, Shao CL, Wang XF, Xie X, Zhang XD, Zhang ZQ, Zhao B, Zhou GS, Zhou J (2013).

Carbon fluxes, evapotranspiration, and water use efficiency of terrestrial ecosystems in China.

Agricultural and Forest Meteorology, 182-183, 76-90.

[本文引用: 1]     

[56] Xu GB, Liu XH, Qin DH, Chen T, An WL, Wang WZ, Wu GJ, Zeng XM, Ren JW (2013).

Climate warming and increasing atmospheric CO2 have contributed to increased intrinsic water-use efficiency on the northeastern Tibetan Plateau since 1850.

Trees, 27, 465-475.

[本文引用: 1]     

[57] Yan JH, Zhang DQ, Liu JX, Zhou GY (2014).

Interactions between CO2 enhancement and N addition on net primary productivity and water-use efficiency in a mesocosm with multiple subtropical tree species.

Global Change Biology, 20, 2230-2239.

[本文引用: 1]     

[58] Yang CP, Jiang J, Tang SS, Li JY, Wang HR (2002).

The provenance test of 21-year old Larix gmelinii at Mao’er- shan area.

Journal of Northeast Forestry University, 30, 1-5.(in Chinese with English abstract)

[本文引用: 1]     

[杨传平, 姜静, 唐盛松, 李景云, 王会仁 (2002).

帽儿山地区21年生兴安落叶松种源试验

. 东北林业大学学报, 30, 1-5.]

[本文引用: 1]     

[59] Zhang XS (1993).

A vegetation-climate classification system for global change studies in China.

Quaternary Sciences, (2), 157-169.(in Chinese with English abstract)

[本文引用: 2]     

[张新时 (1993).

研究全球变化的植被-气候分类系统

. 第四纪研究, (2), 157-169.]

[本文引用: 2]     

[60] Zhu Q, Jiang H, Peng CH, Liu JX, Wei XH, Fang XQ, Liu SR, Zhou GM, Yu SQ (2011).

Evaluating the effects of future climate change and elevated CO2 on the water use efficiency in terrestrial ecosystems of China.

Ecological Modelling, 222, 2414-2429.

[本文引用: 4]     

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