花作为被子植物演化的基础(汤晓辛和黄双全, 2012; 王晓月等, 2019), 在花设计(花颜色、花结构、花气味以及花报酬)和花展示(开花进程、花寿命以及花在花序上的数量、空间排列)组成的花部综合征上表现出多样性或可塑性(Barrett, 1998; 黄双全和郭友好, 2000; 张大勇, 2004; Spigler & Kalisz, 2013)。花部综合征的多态性是在极端环境繁殖限制下的繁殖对策及遗传基因共同作用的结果(Nicotra et al., 2010; Spigler & Kalisz, 2013), 它不仅影响传粉媒介的种类、活动及花粉的有效移出和落置效率, 还影响交配格局、后代适合度以及种群扩散能力(Barrett, 2003; Sun et al., 2005; Wiemer et al., 2011), 并进一步驱动物种进化(阮成江等, 2006; Barrett, 2010)。
动物传粉植物在不同极端环境长期适应过程中通过两个或多种多态的花部结构来适应选择压力(Harder & Johnson, 2009), 并形成较为复杂的繁殖方式和交配对策(Barrett et al., 2000; 张大勇和姜新华, 2001)。自从Darwin (1872)首次提出“异型花柱”的概念以来, 学者们对动物传粉植物的花内雌雄蕊空间位置变化导致的花性状的可塑性进行了较为深入的研究, 并提出不同的观点; 如锦葵科的木棉(Bombax ceiba)黄花个体雌雄异位程度较红花个体更大, 能更有效地避免雌雄功能干扰和自花授粉(向文倩和任明迅, 2019); 龙胆科的线叶龙胆(Gentiana lawrencei var. farreri)花开放后通过花柱逐渐伸长来避免单花内的自交(侯勤正等, 2009); 而姜科山姜属(Alpinia)植物通过花柱卷曲来促进异交(张玲和李庆军, 2002; 孙杉等, 2010)。总之, 被子植物的花在传粉者及交配成功率受到限制的极端环境下改变或向多态性方向演化(Brummell et al., 1999; Barrett, 2003; Bonamour et al., 2019)。
传粉是指花粉通过自身或传粉媒介的作用从花粉囊中散发到自花或异花柱头上并萌发成花粉管的过程(黄双全和郭友好, 2000; Zych et al., 2018)。被子植物的有性繁殖过程要依赖不同的传粉媒介, 其中90%的开花植物通过动物传粉(Navarro et al., 2007; Etcheverry et al., 2008; Ivey & Carr, 2011; Ollerton et al., 2011; Shivanna et al., 2020)来实现多样的传粉策略(泛化传粉和专性传粉), 并影响演化趋向(Li et al., 2001; Zych et al., 2018)。动物传粉植物的传粉往往受到生物因素(传粉者和资源分配等)和非生物因素(气候因子等)的影响(Bosch & Blas, 1994; Elliott & Irwin, 2009); 如在早春荒漠环境中的开花植物更易受到风沙、低温、大风等气候因子的影响, 导致植物物候的推迟、传粉昆虫多样性的降低、昆虫群落结构的变化及传粉者活动减少(施雨含等, 2021), 从而影响植物与传粉者之间报酬和服务的平衡节律, 导致“传粉服务”的损失(Arroyo et al., 1985; Bingham & Orthner, 1998; Bhatnagar et al., 2019), 减少落置到柱头上的花粉, 影响植物的繁殖适合度(张大勇和姜新华, 2001; 吴云等, 2015)。在缺乏传粉者或传粉者间竞争激烈的极端环境中, 植物往往会采取多种繁殖策略实现自身的繁殖保障(段元文等, 2007), 一些高山植物会通过改变花寿命来得到更多的交配机会(Pacheco et al., 2016), 在传粉昆虫少的高原环境中线叶龙胆通过延长花寿命内的柱头可授性时间得到更多的传粉机会(侯勤正等, 2009)。
黑果枸杞(Lycium ruthenicum)在我国主要分布于西北地区, 是国家二级保护的多年生灌木(
图1
图1
黑果枸杞花各部位特征测量(A)和不同花型花花柱及花药相对高度(B)(平均值±标准误)。a(a′)-e(e′), 花冠筒长度; a(a′)-d(d′), 雌蕊长; a(a′)-c(c′), 雄蕊长; f(f′)-b(b′), 花冠口直径。B中不同小写字母表示同一花型花不同性器官间差异显著(p < 0.05)。
Fig. 1
Measurements of flower traits (A) and relative height of sexual organs (B) of two flower morphs of Lycium ruthenicum (mean ± SE). a(a′)-e(e′), flower length; a(a′)-d(d′), pistil length; a(a′)-c(c′), stamen length; f(f′)-b(b′), corolla diameter. Different lowercase letters in B indicate significant difference between different sexual organs of the same flower morph (p < 0.05).
1 材料和方法
1.1 研究材料与研究地点
黑果枸杞隶属于茄科枸杞属, 为多年生灌木, 主要分布于中亚、高加索和欧洲等地区; 在我国生长在甘肃、宁夏、青海、新疆等地海拔1 100-3 200 m区域, 是重要的“药食同源”型植物资源(米吉提·胡达拜尔地和潘晓玲, 2004)。黑果枸杞花为筒状的两性花, 总状花序, 花萼窄钟状, 花瓣和雄蕊均5枚, 雄蕊着生于花冠筒中部; 花刚开放时花瓣紫色, 花后期逐渐转为白色; 花为雌雄蕊长度一致的同位花(戴国礼等, 2013)。而在新疆南部的不同自然种群及不同个体中, 均出现同位花及雌蕊高于雄蕊的异位花(图1A)。我们对新疆南部16个自然种群调查发现该物种种群结构由同位-异位花同株(47%)、同位-异位花同株和同位-异位花异株共存(33%)、同位-异位花异株(20%) 3种类型构成(未发表数据); 该物种在新疆南部荒漠环境中每年3月中旬开始萌芽, 4月中旬开花, 5月中旬开始进入果实阶段。果实黑紫色, 扁平或圆球形浆果, 种子肾形。
本研究于2017-2019年4-6月在新疆喀什市吐曼河周围的黑果枸杞同位-异位花异株的自然种群(39.47° N, 75.98° E; 海拔1 200-1 280 m)(图2)进行。该区域年平均气温12 ℃, 年降水量70 mm, 春季沙尘暴较多, 气候干燥, 属于典型的暖温带荒漠气候。
图2
图2
新疆喀什黑果枸杞的植株、花序、果实、花型及花颜色变化。A, 雌雄异位花。B, 同位花。C, 异位花花序。D, 同位花花序。E, F, 果实。G, 植株。H, 不同花型花在花寿命内的花色变化(上部为同位花, 下部为异位花)。
Fig. 2
Individual plant, inflorescence, fruit, flower morphs and flower color changes in Lycium ruthenicum in Kashi, Xinjiang, China. A, Herkogamous flower. B, Homostylous flower. C, Inflorescence of herkogamous flower. D, Inflorescence of homostylous flower. E, F, Fruit. G, Individual plant. H, Change of flower color in different phases of flower longevity in two flower morphs of L. ruthenicum (upper, homostylous flower; lower, herkogamous flower).
1.2 研究方法
1.2.1 花部特征及性分配特点检测
1.2.1.1 花各部位特征及性分配特点的检测
随机标记处于盛花期的同位及异位植株各20株, 从每个植株随机标记发育良好的花各3朵, 两种类型花各60朵, 共120朵, 在花寿命早期(紫色)以及花后期(白色)(图2A、2B、2H), 均选取20朵带回实验室, 使用便携式SE-2000型数显电子游标卡尺(精度为0.02 mm)测量每朵花的花冠直径、花冠筒长度、雌雄蕊长度(雄蕊的长度为平均雄蕊长度)、雌雄蕊空间距离(雄蕊长度-雌蕊长度)、花冠口与雄蕊间距离(花冠筒长度-雄蕊长度)及花冠口与雌蕊间距离(花冠筒长度-雌蕊长度), 并计算雌(雄)蕊器官相对高度, 雌(雄)蕊相对高度=雌(雄)蕊长度/花冠筒长度。在盛花期内随机选取两种类型植株的新鲜且花药未开裂的花各10朵, 将每一朵花的花药全部取下放在离心管中, 充分压碎, 加入2 mL水充分摇匀制成花粉溶液, 使用5 µL微量进样器将花粉液滴于载玻片上做5个视野点(每个视野点为1 µL), 每朵花重复6次, 在Motic B1型光学显微镜下统计花粉数量, 计算单花总花粉数; 同时将两种类型花的子房置于SZM45型解剖镜下解剖, 统计其胚珠数, 用平均花粉粒数除以胚珠数计算花粉胚珠比(P/O值)。
1.2.1.2 花粉活力和柱头可授期特点检测
用MTT法(Dafni, 2005)检测不同类型花在花寿命早期和后期的花粉活力, 从两种类型植株随机标记即将开放的花各50朵, 在花刚开放(花冠紫色)、花药散粉、花冠淡紫色、花冠白色以及花冠褐色时(图2H)各选取10朵花, 取少许花粉置载玻片上滴加MTT溶液静置10 min后在Motic B1光学显微镜下观察, 若被染成蓝紫色则为有活力的花粉, 未被染色则为无活力花粉, 计算花粉活力百分比(花粉活力百分比=被染色花粉数/(被染色花粉数+未被染色花粉数) × 100%); 同时取花柱头, 用联苯胺-H2O2溶液染色, 若柱头被染成蓝色且有大量的气泡, 则柱头具有可授性, 无气泡或气泡很少则说明柱头没有可授性(Dafni, 2005)。
1.2.2 开花式样观察
为比较该物种同位及异位花植株的开花式样特点, 在自然种群中开展以下实验: (1)种群水平: 记录种群中同位及异位花植株的第一朵花开放到最后一朵花凋落的持续时间; (2)个体水平: 随机标记大小不同的同位及异位花各20个植株, 记录每个植株上第一朵花开放到最后一朵花凋落的持续时间; (3)单花水平: 从不同花型植株中随机选取10株, 从每个植株选取4个花苞, 各40朵花, 观察并记录花寿命(花蕾打开至花凋落的持续时间)。
1.2.3 花报酬的测定
为了检测两种类型花在花寿命早期和后期的花报酬(花蜜)是否存在差异, 每天从两种类型花植株随机标记将要开放的花各选10朵并套网袋, 在紫色和白色阶段用2 μL毛细管对标记花的花蜜分泌量(μL)进行测量, 每次测量在同一朵花上进行, 测完后套袋以隔离传粉者, 重复3次。另取两种类型花植株紫色和白色阶段的花各70朵, 放入20 mL顶空瓶内, 用压盖器封紧瓶盖, 室温放置2 h后用Portable Electronic Nose PEN3型电子鼻(Airsense Analytics, Schwerin, Germany), 10种传感器检测不同类型花花气味中的化学成分, 计算每种化合物占总化合物含量的百分比, 检测时间调至60 s, 传感器自动清洗时间调至120 s, Connectvial倒计时提示1 s时, 同时将进样针和补气针插入顶空进样器至瓶身2/3处, 开始检测挥发性物质, 当Removevial倒计时提示1 s时迅速拔出进样针和补气针, 停止检测, 各重复检测3次。
1.2.4 传粉生物学特性观测
在盛花期晴朗天气里, 随机标记同位和异位花植株各10个, 从每个植株选取随机标记发育良好且第二天早晨即将开放的花5朵, 在单花花期内的每天10:00-18:00 (每小时观测30 min, 每天共观测 240 min), 观测昆虫访花频率及停留时间的变化规律; 同时, 通过摄影仪拍摄主要传粉者在花寿命早期和后期的访花行为变化规律。用昆虫网捕获昆虫(每种6只), 放入毒瓶致死后, 将各类访花昆虫的一部分制成标本用于种类鉴定, 另一部分在Nikon SMZ-800N型数码体视解剖镜下观察携粉部位, 并用70%的乙醇冲洗数次, 将冲洗液涂片置Motic B1型光学显微镜下, 通过昆虫携带的花粉与不同花型花的花粉比较观察, 以判断其是否为传粉者。
1.2.5 传粉效率、坐果率及结籽率检测
为了检测同位及异位花在花寿命早期和后期的花粉传递效率及其坐果率和结籽率间的差异, 在盛花期选取两种类型花植株各10株, 从每个植株上标记发育状态及大小一致的花6朵, 做以下3种实验: (1)花颜色褪色为淡紫色时(紫色阶段), 从不同花型植株已标记的花中选取2朵, 将其柱头和5枚花药分别且对应地放在5 mL的离心管内, 将花药捣碎, 加入2 mL水制成花粉溶液, 摇匀后使用5 µL微量进样器将花粉液滴于载玻片上做5个视野点(每个视野点为1 µL), 在Motic B1型光学显微镜下统计每朵花花药内剩余的花粉数, 每朵花重复6次; 将柱头置于载玻片上滴加1-2滴蒸馏水, 在Motic B1型光学显微镜下统计落置在柱头上的花粉数; (2)花快掉落时(白色阶段), 从不同花型植株各另选已标记的2朵花, 将其柱头和花药分别且对应地放在离心管内, 统计落置在柱头上的花粉数以及每朵花花药内剩余的花粉数; (3)不同花型各植株剩余的2朵花做标记, 在果实成熟时, 统计坐果率和结籽率。参照Gong和Huang (2014)的方法计算花粉传递效率(PE), PE = D/(P - R) × 100%, 其中D为每朵花落置到柱头上的总花粉数, P为单花总花粉数, R为每朵花上剩余花粉数; 紫色阶段被移出花粉数=单花平均花粉数-紫色阶段花上剩余的花粉数, 而白色阶段被移出花粉数=紫色阶段花上剩余的花粉数-快掉落花上剩余的花粉数。花寿命早期和后期的花粉移出率(PR)通过公式PR = (P - R)/P × 100%来计算, 其中的P为单花总花粉数或紫色阶段花上剩余的花粉数, R为不同颜色阶段花上剩余的花粉数。
1.3 数据分析
数据分析在SPSS 22.0软件中进行, 所有数据在分析前均进行方差齐性和正态分布检验, 对服从正态分布的数据, 利用广义线性模型中的正态分布模型-恒定函数, 种群花期、个体花期、单花寿命、花部特征、花蜜体积、访花频率、停留时间作为自变量, 两种花型作为因变量进行比较分析。利用泊松分布模型-对数线性函数, 两种花型的花粉数、胚珠数、柱头落置花粉数作为自变量, 两种花型作为因变量进行比较分析。坐果率及结籽率采用二项式分布-Logistic关联函数分析比较。所有统计数据用平均值±标准误表示, 使用SigmaPlot 10.0软件作图。
2 结果和分析
2.1 两种类型花性状
黑果枸杞两种类型花的花部特征受到阶段、花型及阶段和花型交互作用不同程度的影响(表1)。其中同位花在花寿命早期(紫色)和后期(白色)的花冠直径、花冠筒长度及雄蕊长度均比异位花长, 而异位花在花寿命早期和后期的雌-雄蕊空间距离均比同位花长(表1)。异位花雌雄蕊相对高度间存在极显著差异(Wald χ2 = 15.263, p < 0.001, 图1B), 反而同位花间无显著差异(Wald χ2 = 1.668, p = 0.196)。此外, 该物种花的雌蕊在花寿命内有一定的生长, 其中异位花类型更明显(表1)。异位花的花粉数(486 750 ± 142.4)比同位花(188 900 ± 79.4)多, 且花粉胚珠比(21 118.4 ± 1 122.5)比同位花(12 714.2 ± 857.3)高, 并且二者间均存在极显著差异(Wald χ2花粉数 = 3 418 750.190, p < 0.001; Wald χ2P/O = 35.410, p < 0.001), 反而后者的胚珠数(21.3 ± 1.1)比前者(17.3 ± 0.8)多, 且二者间存在显著差异(Wald χ2 = 359.720, p < 0.001)。
表1 黑果枸杞同位花和雌雄异位花在花寿命早期(紫色)和后期(白色)花部特征(平均值±标准误)的比较(广义线性模型)
Table 1
| 花部特征 Flower characteristic | 紫色阶段 Purple phase | 白色阶段 White phase | 花型×阶段 Morph × phase | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 同位花 Homostylous flower | 雌雄异位花 Herkogamous flower | Wald χ12 | p1 | 同位花 Homostylous flower | 雌雄异位花 Herkogamous flower | Wald χ22 | p2 | Wald χ32 | p3 | |
| 花冠直径 Corolla diameter (mm) | 8.29 ± 0.25 | 7.36 ± 0.33 | 10.411 | 0.001 | 7.18 ± 0.23 | 6.70 ± 0.43 | 0.914 | 0.659 | 17.380 | 0.001 |
| 花冠筒长 Corolla tube length (mm) | 14.28 ± 0.31 | 10.70 ± 0.54 | 32.514 | <0.001 | 14.92 ± 0.39 | 9.71 ± 0.57 | 57.284 | <0.001 | 4.188 | 0.242 |
| 雌蕊长 Pistil length (mm) | 11.99 ± 0.33 | 12.20 ± 0.57 | 0.104 | 0.747 | 12.06 ± 0.33 | 13.07 ± 0.48 | 3.005 | 0.083 | 0.043 | 0.998 |
| 雄蕊长 Stamen length (mm) | 11.99 ± 0.24 | 10.20 ± 0.42 | 13.574 | <0.001 | 12.37 ± 0.36 | 11.14 ± 0.53 | 3.745 | 0.053 | 1.481 | 0.687 |
| 雌雄蕊空间距离 Stamen-stigma distance (mm) | 0.65 ± 0.16 | 2.00 ± 0.27 | 18.588 | <0.001 | 1.02 ± 0.18 | 1.93 ± 0.27 | 8.042 | 0.005 | 4.358 | 0.225 |
| 雌蕊-花冠口距离 Corolla tube-stigma distance (mm) | 2.29 ± 0.22 | 1.50 ± 0.39 | 3.175 | 0.075 | 2.86 ± 0.28 | 3.36 ± 0.42 | 0.975 | 0.323 | 12.430 | 0.006 |
| 雄蕊-花冠口距离 Corolla tube-stamen distance (mm) | 0.70 ± 0.28 | 2.29 ± 0.16 | 24.444 | <0.001 | 2.55 ± 0.29 | 1.86 ± 0.42 | 1.865 | 0.172 | 1.208 | 0.751 |
Wald χ12、Wald χ22表示在不同阶段不同花型花部特征各指标之间的比较,Wald χ32表示阶段和花型之间的交互作用。
Wald χ12, Wald χ22 refers to the comparison of flower characteristics between two flower morphs at different phases; Wald χ32 represents the interaction between phase and morph.
图3
图3
黑果枸杞不同花型花紫色阶段(1、2和3)和白色阶段(4和5)花粉活力及柱头可授性比较(平均值±标准误)。“+”表示柱头可授性强弱程度。
Fig. 3
Pollen viability and stigma acceptability in purple phase (1, 2 and 3) and white phase (4 and 5) of two flower morphs of Lycium ruthenicum (mean ± SE). “+” indicates the degree of acceptability of stigma.
2.2 两种类型花开花式样
黑果枸杞在喀什自然种群中3月中旬开始萌芽, 在4月中旬开花, 种群中同位花个体所占比例(68%)高于异位花个体(32%)。种群水平上, 同位及异位花植株的花期之间存在极显著差异(Wald χ2 = 1 459.545, p < 0.001), 其中同位花植株的种群水平花期(4月中旬至8月, (117.00 ± 2.25) d)比异位花植株长(4月下旬至5月下旬, (26.00 ± 1.00) d)。而个体水平上, 同位花个体的花期((101.65 ± 1.98) d)比异位花个体((18.75 ± 1.00) d)长, 二者之间存在极显著差异(Wald χ2 = 1 472.949, p < 0.001)。异位花的单花寿命((4.50 ± 0.14) d)比同位花((3.13 ± 0.11) d)长, 并且二者间存在极显著差异(Wald χ2 = 59.563, p < 0.001); 两种类型花在花寿命内紫色阶段的持续时间比白色阶段长。
2.3 两种类型花花报酬
黑果枸杞两种类型花的花报酬均为花蜜和花粉, 蜜腺位于花冠筒的基部, 花蜜为无色分泌物。同位花在花寿命早期和后期产生的花蜜量均高于异位花(图4), 其中两种类型花在紫色阶段的花蜜量呈极显著差异(Wald χ2 = 11.975, p < 0.001), 在白色阶段的花蜜量无显著差异(Wald χ2 = 2.636, p = 0.104); 同位和异位花在紫色阶段分泌的花蜜量往往高于白色阶段的花蜜量(Wald χ2同位花 = 14.934, p < 0.001; Wald χ2异位花 = 6.236, p = 0.013, 图4)。两种类型花均分泌10大类化合物, 其中有4类芳香类化合物(表2)。同位花(35.73% ± 1.34%)和异位花(35.29% ± 0.71%)在紫色阶段分泌的芳香类化合物含量无显著差异(Wald χ2 = 0.140, p = 0.708), 而异位花在白色阶段分泌的芳香类物质含量(33.91% ± 0.16%)高于同位花(32.02% ± 0.51%)且差异极显著(Wald χ2 = 18.723, p < 0.001, 图4)。
图4
图4
黑果枸杞不同花型花在花寿命早期(紫色)和后期(白色)的花蜜分泌量(平均值±标准误)。不同大写字母表示同种类型不同阶段间的差异显著, 不同小写字母表示同一阶段不同花型间的差异显著(p < 0.05)。
Fig. 4
Nectar volume at early flowering phase (purple) and late phase (white) of two flower morphs of Lycium ruthenicum (mean ± SE). Different uppercase letters indicate significant difference between different phases of the same flower morph, and different lowercase letters indicate significant difference between different flower morphs at the same phase (p < 0.05).
表2 新疆喀什黑果枸杞不同花型花在花寿命不同阶段(紫色和白色)花气味中的化学成分占总化合物百分比(平均值±标准误)的比较
Table 2
| 传感器 Sensor | 物质 Substance | 紫色阶段 Purple phase | 白色阶段 White phase | 花型×阶段 Morph × phase | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 同位花 Homostylous flower | 雌雄异位花 Herkogamy flower | Wald χ12 | p1 | 同位花 Homostylous flower | 雌雄异位花 Herkogamy flower | Wald χ22 | p2 | Wald χ32 | p3 | ||
| W1C | 芳香成分苯类 Benzenoids | 8.58 ± 0.37 | 9.26 ± 0.46 | 1.408 | 0.235 | 6.31 ± 0.20 | 8.23 ± 0.04 | 130.437 | <0.001 | 3.385 | 0.066 |
| W3C | 氨类, 芳香成分 Ammonia, benzenoids | 8.19 ± 0.40 | 7.01 ± 1.49 | 0.463 | 0.496 | 5.45 ± 0.27 | 7.76 ± 0.05 | 106.682 | <0.001 | 3.120 | 0.077 |
| W5C | 烷烃芳香成分 Alkane aromatic composition | 8.06 ± 0.41 | 8.92 ± 0.55 | 1.566 | 0.211 | 5.28 ± 0.28 | 7.64 ± 0.05 | 103.141 | <0.001 | 3.424 | 0.064 |
| W2W | 芳香成分, 有机硫化物 Benzenoids, organic sulfide | 10.92 ± 0.39 | 10.11 ± 0.27 | 4.025 | 0.045 | 14.97 ± 0.24 | 10.28 ± 0.22 | 309.736 | <0.001 | 87.539 | <0.001 |
| W1S | 甲基类 Methyl | 19.83 ± 0.55 | 15.87 ± 1.60 | 4.450 | 0.035 | 25.47 ± 1.01 | 19.86 ± 0.31 | 42.106 | <0.001 | 0.531 | 0.466 |
| W1W | 无机硫化物 Inorganic sulfide | 7.61 ± 2.61 | 10.25 ± 0.22 | 2.484 | 0.115 | 13.67 ± 0.19 | 10.48 ± 0.14 | 267.990 | <0.001 | 9.389 | 0.002 |
| W2S | 醇类, 醛酮类 Alcohols, aldehydes and ketones | 10.40 ± 0.30 | 10.67 ± 0.14 | 1.223 | 0.269 | 10.92 ± 0.39 | 10.70 ± 0.10 | 0.357 | 0.550 | 0.279 | 0.598 |
| W3S | 烷烃 Alkane | 8.28 ± 0.40 | 8.99 ± 0.53 | 1.131 | 0.288 | 5.37 ± 0.27 | 7.77 ± 0.04 | 112.877 | <0.001 | 4.695 | 0.030 |
| W5S | 氮氧化合物 Nitrogen oxides | 9.68 ± 0.29 | 9.85 ± 0.33 | 0.160 | 0.689 | 7.41 ± 0.36 | 9.35 ± 0.09 | 40.361 | <0.001 | 10.389 | 0.001 |
| W6S | 氢化物 Hydride | 8.46 ± 0.39 | 9.08 ± 0.51 | 0.952 | 0.329 | 5.46 ± 0.26 | 7.93 ± 0.05 | 125.947 | <0.001 | 6.120 | 0.013 |
Wald χ12、Wald χ22表示不同花型在不同阶段花气味化学成分之间的比较, Wald χ32表示不同花型和不同阶段之间的交互作用。
Wald χ12, Wald χ22 refers to the comparison of flower odour chemicals between two flower morphs at different phases; Wald χ32 represents the interaction between phase and morph.
2.4 传粉昆虫及访花行为
黑果枸杞两种类型花在喀什自然种群的访花者均为熊蜂(Bombus sp.)、意大利蜜蜂(Apis mellifera)、食蚜蝇(Syrphidae)、淡脉隧蜂(Lasioglossum occidens)、丝光绿蝇(Lucilia sericata)及蚂蚁(Tetramorium sp.); 其中的熊蜂、意大利蜜蜂、食蚜蝇是两种类型花的共同传粉者(图5), 传粉昆虫在花寿命早期和后期访花行为存在差异, 紫色阶段的访花频率往往比白色阶段高(图6)。其中意大利蜜蜂和熊蜂在两种类型花的花寿命早期和后期的访花频率均存在显著差异, 在紫色阶段二者在同位花上的访花频率均比异位花高(Wald χ2意大利蜜蜂 = 4.660, p = 0.031; Wald χ2熊蜂 = 4.292, p = 0.038); 而在白色阶段二者在异位花上的访花频率往往比同位花高(Wald χ2意大利蜜蜂 = 4.706, p = 0.030; Wald χ2熊蜂 = 5.625, p = 0.018)。在紫色阶段传粉者在同位花上的停留时间比异位花长, 其中意大利蜜蜂在两种类型花上停留时间差异显著(Wald χ2 = 8.732, p = 0.003)。
图5
图5
黑果枸杞主要访花昆虫。A, 意大利蜜蜂。B, 熊蜂。C, 食蚜蝇。D, 淡脉隧蜂。E, 丝光绿蝇。
Fig. 5
Main visiting insects of Lycium ruthenicum. A, Apis mellifera. B, Bombus sp. C, Syrphidae. D, Lasioglossum occidens. E, Lucilia sericata.
图6
图6
黑果枸杞不同花型花主要传粉者在花寿命早期(紫色)和后期(白色)的访花频率及停留时间(平均值±标准误)。不同大写字母表示同种花型不同传粉者间的差异, 不同小写字母表示同一传粉者不同花型间的差异显著(p < 0.05)。
Fig. 6
Visiting frequency of main pollinators at early flowering phase (purple) and late flowering phase (white) of Lycium ruthenicum of two flower morphs (mean ± SE). Different uppercase letters indicate significant difference between different pollinators of the same morph, and different lowercase letters indicate significant difference between different flower morphs of same pollinator (p < 0.05).
2.5 传粉效率、坐果率及结籽率
在花寿命早期和后期同位花的花粉移出率、花粉落置数及花粉传递效率均比异位花高(图7A-7C); 并且同位和异位花在花寿命早期和后期的花粉移除率(Wald χ2紫色 = 21.805, p < 0.001; Wald χ2白色 = 23.087, p < 0.001)、柱头花粉落置数(Wald χ2紫色 = 3.599, p = 0.050; Wald χ2白色 = 20.910, p < 0.001)及花粉传递效率(Wald χ2紫色 = 10.379, p = 0.01; Wald χ2白色 = 32.555, p < 0.001)间均存在显著差异。同位花的自然坐果率(69.27% ± 5.99%)及结籽率(72.75% ± 5.27%)均比异位花的自然坐果率(51.13% ± 2.87%)及结籽率(55.22% ± 4.56%)高, 并且二者的坐果率和结籽率存在显著差异(Wald χ2坐果率 = 76.248, p < 0.001; Wald χ2结籽率 = 6.480, p = 0.01, 图7D)。
图7
图7
黑果枸杞不同花型花在花寿命早期(紫色)和晚期(白色)花粉移出率(A)、柱头落置花粉数(B)、花粉传递效率(C)、自然坐果率和结籽率(D)(平均值±标准误)。A-C不同大写字母表示同种花型不同阶段间的差异显著, 不同小写字母表示不同花型间差异显著(p < 0.05)。
Fig. 7
Proportion of total pollen grains removed (A), deposited pollen grains (B), pollen transfer efficiency (C) and fruit and seed set rate (D) in the two flower morphs of Lycium ruthenicum at early flowering phase (purple) and late flowering phase (white)(mean ± SE). Different uppercase letters indicate significant difference between different phases of the same morph, and different lowercase letters indicate significant difference between different flower morph at the same phase (p < 0.05).
3 讨论
3.1 花部综合征的差异
被子植物的花作为植物演化的基本单位在结构上具有多样化的适应机制, 并通过花大小、颜色、花气味、雌雄蕊空间位置及花粉活力和柱头可授性、花寿命不同阶段的动态变化等多样化的花部特征来保障繁殖成功(Ashman et al., 2004; 张大勇, 2004; He et al., 2005; Abdusalam et al., 2021)。动物传粉植物常常通过改变开花式样及花药和柱头的接近距离等花部特征来保障繁殖和母本适合度(Webb & Lloyd, 1986; Barrett et al., 2000; Cheptou, 2012); 其中柱头和花药的结构、位置和时间上的分离及变化程度一直被认为是应对恶劣气候条件及避免自交和雌雄性器官功能干扰而演化的花部机制, 它们会直接影响植物繁殖成功率(Brummell et al., 1999; Barret, 2003; Oliveira et al., 2022); 如草地老鹳草(Geranium pratense)通过雌雄蕊空间距离及雌雄异熟特征来避免雌雄功能干扰(Abdusalam et al., 2021)。在本研究中, 黑果枸杞在花寿命内雌雄蕊空间位置较稳定, 同位花的雌蕊和雄蕊长度无显著差异, 而异位花有较大的雌雄蕊空间距离(表1); 两种类型花柱头可授性和花粉活力均具有较高的同步性, 属于半同熟类型。同位花雌雄蕊功能在空间和时间上的重叠会促进传粉者活动导致的花内传粉及自交(Charlesworth & Charlesworth, 1979; 张大勇, 2004), 该类群同位花表现出适应缺乏传粉者的早春荒漠极端环境下保障自花传粉的花部特征; 而异位花表现出通过雌雄蕊的空间隔离来减小雌雄功能干扰、避免花内花粉传递及促进异花传粉的花部特征。两种类型花的雌雄蕊在空间上的隔离程度是导致二者在花结构上分化的主要因素。
花寿命具有很强的可塑性, 环境的变化往往会改变花寿命的长短(Clark & Husband, 2007; 张志强和李庆军, 2009; Torres-Díaz et al., 2011), 延长花寿命是植物在传粉者稀少的情况下确保传粉成功的一个重要策略(Primack, 1985; Ashman & Schoen, 1994; Ishii & Sakai, 2002), 例如姜科植物毛姜花原变种(Hedychium villosum var. villosum)在传粉者稀少和不稳定的高山环境中通过较长的花寿命提高传粉成功率和坐果率以及花粉输出率来提高雌雄适合度(高江云等, 2009), 短穗柽柳(Tamarix laxa)通过延长开花时间吸引更多有效的传粉者, 减少在南疆早春极端环境导致的花粉限制(艾沙江·阿不都沙拉木和古丽扎尔·阿不都克力木, 2018)。本研究中, 异位花单花寿命比同位花长, 这可能是促进具有异花传粉花部特征的异位花, 在传粉者或授粉限制的极端环境下, 通过延长花寿命得到更多的访问机会来减少繁殖损失, 并且实现繁殖成功(Webb & Lloyd, 1986; Cheptou, 2012)。两种类型花表现出的花部特征均与其他种群研究结果一致, 总之, 该物种两种类型花在雌雄蕊空间位置、花报酬及花寿命上的差异是二者为了保障繁殖成功演化出的花部综合征。
3.2 传粉生物学特性及雄性繁殖特点
传粉是被子植物授精的必经阶段, 昆虫与植物进化过程中形成了相互共生的体系(Barrett, 2010; Ivey & Carr, 2011), 虫媒传粉的开花植物通过花部综合征与传粉昆虫间形成的“以报酬换服务”的关系维持传粉者规律性的访问关系并完成雌雄繁殖过程。丰富的花报酬、鲜艳的花颜色及花气味能向传粉者提供信号, 并促进传粉者的访问频率和传粉过程(Nuttman et al., 2006; Ida & Kudo, 2010), 能影响传粉昆虫在花上的活动、传粉及雄性繁殖率(Sun et al., 2005; Wiemer et al., 2011)。花报酬及花信号(颜色及气味)及其动态变化是影响花粉移出和落置过程的关键因素。在本研究中, 两种类型花早期(紫色)产生的花蜜量比后期(白色)多, 同位花在花寿命早期和后期产生的花蜜量均比异位花产生的花蜜多(图4); 传粉者活动与花报酬间存在相互促进作用, 因此该物种在花报酬较丰富的紫色阶段有较高的访花频率及较长的停留时间, 且花报酬较丰富的同位花的访花频率及停留时间均比异位花高。在虫媒传粉的开花植物中, 花色素和花分泌的特殊气味能够引起传粉者的视觉、识别和行为反应, 是重要的蜜导信号(黄双全和郭友好, 2000; 张大勇, 2004); 该物种两种花型花在花寿命内花色由鲜艳的紫色逐步褪色为褐色(图2H), 这导致在褪色阶段两种类型花的访花频率和停留时间均减少(图6)。在花寿命早期和后期内两种花型均分泌4类芳香类化合物(表2), 且异位花芳香类物质的分泌量均比同位花高, 异位花在白色阶段分泌更多的芳香物质来吸引昆虫。传粉者的觅食行为能够影响花粉移出和落置到柱头的水平, 在花药和花柱头等高的同位花内传粉者活动能将其自花花粉落置到柱头上, 引起辅助自花授粉, 因此该类型柱头有较高的花粉落置数(图7B)。同位花通过丰富的花报酬及花气味吸引更多的昆虫, 获得高的访花频率、花粉移出率、柱头落置花粉数及花粉传递效率, 因此该类型有较高的坐果率及结籽率(图7D)。探出式柱头可以通过提高柱头与传粉者身体的接触机会促进花粉的有效传递(Campbell et al., 1996; Nishihiro et al., 2000), 而该物种异位花在传粉者限制的早春极端环境下, 低的花报酬和低的访花频率, 导致其较低的花粉落置和传粉效率, 因此该类型坐果率和结籽率较低(图7D)。总之, 该物种两种类型花花部特征以及花报酬的差异影响了二者的雄性及雌性繁殖率。
3.3 花部特征与传粉生物特性对繁殖的影响
动物传粉植物的花部综合征不仅影响其对传粉者的吸引、花粉散布、传粉者访花行为、自花和异花授粉程度以及雌雄适合度, 而且进一步影响植物的繁殖成功率(Barrett & Harder, 1996; 张大勇, 2004)。在新疆南部沙尘暴环境早春开花的黑果枸杞所面临的环境具有低温、沙尘暴、多风等气候特点可能导致该物种在传粉过程的传粉者及授粉限制(Arroyo et al., 2013; Abdusalam & Tan, 2014); 本研究中, 异位花的访花频率及坐果率比同位花低, 这与二者的传粉者及授粉限制以及自交亲和性相关, 其中属于自交不亲和类型的异位花(自交亲和性系数为0.136)的授粉限制比部分自交不亲和类型的同位花(自交亲和性系数为0.351)更明显(未发表数据); 因此, 部分自交不亲和的同位花通过表现出自花传粉的花部综合征来减少早春沙尘暴极端环境下的授粉压力。
该物种同位花在花部结构、花报酬及花信号上表现出吸引传粉者、促进花内花粉传递的花部特征, 反而异位花在花部结构、花报酬及花信号上表现出促进花间传粉传递的花部特征。同位花虽然吸引更多的传粉者, 但雌雄蕊空间位置及雌雄半同熟的花设计促进其雌雄功能干扰程度和花内花粉传递过程, 并通过较高的传粉效率及自交亲和性来提高坐果率; 而异位花较大的雌雄蕊空间距离、较低的花报酬和访花频率限制其花粉移出和落置及较低的自交亲和性, 导致其传粉效率和自然坐果率降低。因此, 异位花通过延长花寿命来应对沙尘暴环境中传粉者不足导致的花粉限制。在南疆早春沙尘暴等极端环境中, 同位花具有适应于自花传粉的花部综合征来降低面临的花粉限制及保障繁殖成功, 而以演化出异花传粉为主的花部特征的异位花则面临更高的花粉限制。因此, 在缺乏传粉者或外源花粉时同位花通过花内花粉传递、较短的花寿命及较高的自交亲和性来保障繁殖成功。我们在另外的研究中发现其异位花的异交率(83.33%)较同位花(70.31%)高, 异位花在不同种群的基因组(2.64 ± 0.012 Gb)比同位花(2.62 ± 0.006 Gb)大(未发表结果), 说明其异位花的遗传多样性比自交亲和性高的同位花高, 但二者后代适合度的差异未知。因此, 新疆南部沙尘暴环境对该物种两种类型花繁殖成功的影响还有待进一步在不同种群间研究。总之, 该物种通过自交亲和性较高的同位花保障繁殖和保持种群稳定性, 而通过异位花保障种群更新和扩大的繁殖格局, 这些特点是该物种为了繁殖保障及后代的连续性的繁殖对策。
致谢
感谢云南省植物繁殖适应与进化生态学重点实验室开放课题(KC10114119)资助。
参考文献
Pollination characteristics of two sympatrically distributed Tamarix species in south Xinjiang, China
同域分布柽柳属两种植物的传粉生物学研究
Pollination adaptations of group-by-group stamen movement in a meadow plant with temporal flower closure
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[本文引用: 2]
Floral sexual organ (stamen and pistil) movements are selective adaptations that have different functions in male-female reproduction and the evolution of flowering plants. However, the significance of stamen movements in the spatial-temporal function and separation of male and female organs has not been experimentally determined in species exhibiting floral temporal closure. The current study investigated the role of slow stamen (group-by-group) movement in male-female sexual function, and the effect of stamen movement on pollen removal, male-male and male-female interference, and mating patterns of <i>Geranium pratense</i>, a plant with temporal floral closure. This species uses stamen group-by-group movement and therefore anther-stigma spatial-temporal separation. Spatial separation (two whorls of stamen and pistil length) was shown to be stronger than temporal separation. We found that stamen movements to the center of the flower increase pollen removal, and the most common pollinators visited more frequently and for longer durations during the male floral stage than during the female floral stage. Petal movements increased both self-pollen deposition rate and sexual interference in <i>G. pratense</i>. The fruit and seed set of naturally and outcrossed pollinated flowers were more prolific than those of self-pollinated flowers. Group-by-group stamen movement, dehiscence of stamens, pistil movement, and male-female spatial-temporal functional separation of <i>G. pratense</i> before floral temporal closure may prevent male-female and stamen-stamen interference and pollen discounting, and may increase pollen removal and cross-pollination.
Contribution of temporal flower closure to reproductive success of the spring-flowering Tulipa iliensis
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Community studies in pollination ecology in the high temperate Andes of central Chile. II. Effect of temperature on visitation rates and pollination possibilities
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Temperature-driven flower longevity in a high-alpine species of Oxalis influences reproductive assurance
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PMID:23952472
[本文引用: 1]
How high-alpine plants confront stochastic conditions for animal pollination is a critical question. We investigated the effect of temperature on potential flower longevity (FL) measured in pollinator-excluded flowers and actual FL measured in pollinated flowers in self-incompatible Oxalis compacta and evaluated if plastically prolonged potential FL can ameliorate slow pollination under cool conditions. Pollinator-excluded and hand-pollinated flowers were experimentally warmed with open-top chambers (OTCs) on a site at 3470 m above sea level (asl). Flower-specific temperatures, and pollinator-excluded and open-pollination flower life-spans were measured at six alpine sites between 3100 and 3470 m asl. Fruit set was analyzed in relation to inferred pollination time. Warming reduced potential FL. Variable thermal conditions across the alpine landscape predicted potential and actual FL; flower senescence was pollination-regulated. Actual FL and potential FL were coupled. Prolonged potential FL generally increased fruit set under cooler conditions. Plastic responses permit virgin flowers of O. compacta to remain open longer under cooler temperatures, thereby ameliorating slow pollination, and to close earlier when pollination tends to be faster under warmer conditions. Plastic potential FL provides adaptive advantages in the cold, thermally variable alpine habitat, and has important implications for reproductive success in alpine plants in a warming world. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.
Pollen limitation of plant reproduction ecological and evolutionary causes and consequences
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How long should flowers live?
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The evolution of mating strategies in flowering plants
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Mating strategies in flowering plants: the outcrossing-selfing paradigm and beyond
Understanding plant reproductive diversity
Ecology and evolution of plant mating
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The evolution and function of stylar polymorphisms in flowering plants
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Effect of climate change on plants and their pollinators: a review
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Efficient pollination of alpine plants
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Phenotypic plasticity in response to climate change: the importance of cue variation
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Foraging behaviour and pollinating efficiency of Osmia cornuta and Apis mellifera on almond (Hymenoptera: Megachilidae, Apidae)
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Differential expression of expansin gene family members during growth and ripening of tomato fruit
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A model for the evolution of distyly
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Review: part of a special issue on plant mating systems, Clarifying Baker’s Law
DOI:10.1093/aob/mcr127
PMID:21685434
[本文引用: 2]
Baker's Law states that colonization by self-compatible organisms is more likely to be successful than colonization by self-incompatible organisms because of the ability for self-compatible organisms to produce offspring without pollination agents. This simple model has proved very successful in plant ecology and has been applied to various contexts, including colonizing or ruderal species, islands colonizers, invasive species or mating system variation across distribution ranges. Moreover, it is one of the only models in population biology linking two traits of major importance in ecology, namely dispersal and mating system. Although Baker's Law has stimulated a large number of empirical studies reporting the association of self-fertilization and colonizing ability in various contexts, the data have not established a general pattern for the association of traits.In this paper, a critical position is adopted to discuss and clarify Baker's Law. From the literature referring to Baker's Law, an analysis made regarding how mating success is considered in such studies and discrepancies with population genetics theory of mating systems are highlighted. The data reporting the association of self-fertilization and colonizing ability are also briefly reviewed and the potential bias in interpretation is discussed. Lastly, a recent theoretical model analysing the link between colonizing ability and self-fertilization is considered.Evolutionary predictions are actually more complex than Baker's intuitive arguments. It appears that Baker's Law encompasses a variety of ecological scenarios, which cannot be considered a priori as equivalent. Questioning what has been considered as self-evident for more than 50 years seems a reasonable objective to analyse in-depth dispersal and mating system traits.
Plasticity and timing of flower closure in response to pollination in Chamerion angustifolium (Onagraceae)
DOI:10.1086/513486 URL [本文引用: 1]
黑果枸杞的花部结构及繁育系统特征
高山植物扁蕾的延迟自交机制
DOI:10.17521/cjpe.2007.0014
[本文引用: 1]
扁蕾（Gentianopsis barbata）具有鲜艳的花和显著的腺体，并且花开放的前5 d 柱头和花药始终处于不同的位置（雌雄异位），这些花综合征表明该植物应为异花传粉。为检验这一假设，我们对青藏高原植物扁蕾的海北站种群进行了3年的传粉生物学研究实验。与花综合征所表明的繁育系统相反，两年的野外观察发现昆虫的访花频率十分低，不去雄并隔离昆虫处理也能产生大量种子，说明这一种群的繁殖主要是依赖于自花传粉。尽管利用种子结实评价的柱头可授性从花开放4 d后开始下降，但随着花的发育进程，雄蕊的伸长能使得花药与柱头完全接触。实验也证明，柱头可授性和花粉活力都超过5 d，说明花药和柱头的接触能够发生自花授粉。扁蕾的这种自花传粉机制应属于典型的延迟自交类型。自花授粉发生在单花花期快要结束前，自交之前仍然保持异交传粉机制，这种延迟自交避免了自交与异交竞争造成的花粉或者种子折损，并为扁蕾在青藏高原极端环境下由于访花昆虫缺乏造成的异交失败提供了繁殖保障。
Effects of flowering plant density on pollinator visitation, pollen receipt, and seed production in Delphinium barbeyi (Ranunculaceae)
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PMID:21628244
[本文引用: 1]
Variation in flowering plant density can have conflicting effects on pollination and seed production. Dense flower patches may attract more pollinators, but flowers in those patches may also compete for pollinator visits and abiotic resources. We examined how natural and experimental conspecific flowering plant density affected pollen receipt and seed production in a protandrous, bumble bee-pollinated wildflower, Delphinium barbeyi (Ranunculaceae). We also compared floral sex ratios, pollinator visitation rates, and pollen limitation of seed set from early to late in the season to determine whether these factors mirrored seasonal changes in pollen receipt and seed production. Pollen receipt increased with natural flowering plant density, while seed production increased across lower densities and decreased across higher flower densities. Experimental manipulation of flowering plant density did not affect pollinator visitation rate, pollen receipt, or seed production. Although pollinator visitation rate increased 10-fold from early to late in the season, pollen receipt and seed set decreased over the season. Seed set was never pollen-limited. Thus, despite widespread effects of flowering plant density on plant reproduction in other species, the effects of conspecific flowering plant density on D. barbeyi pollination and seed production are minor.
Flower morphology, pollination biology and mating system of the complex flower of Vigna caracalla (Fabaceae: papilionoideae)
DOI:10.1093/aob/mcn106
PMID:18587133
[本文引用: 1]
Vigna caracalla has the most complex flower among asymmetrical Papilionoideae. The objective of this study was to understand the relationships among floral characteristics, specialization, mating system and the role of floral visitors under different ecological contexts.Five populations were studied in north-western Argentina, from 700 to 1570 m a.s.l. Anthesis, colour and odour patterns, stigmatic receptivity, visitors and pollination mechanism were examined and mating-system experiments were performed.The petals are highly modified and the keel shows 3.75-5.25 revolutions. The sense of asymmetry was always left-handed. Hand-crosses showed that V. caracalla is self-compatible, but depends on pollinators to set seeds. Hand-crossed fruits were more successful than hand-selfed ones, with the exception of the site at the highest elevation. Bombus morio (queens and workers), Centris bicolor, Eufriesea mariana and Xylocopa eximia trigger the pollination mechanism (a 'brush type'). The greatest level of self-compatibility and autonomous self-pollination were found at the highest elevation, together with the lowest reproductive success and number of pollinators (B. morio workers only).Self-fertilization may have evolved in the peripheral population at the highest site of V. caracalla because of the benefits of reproductive assurance under reduced pollinator diversity.
Effects of flower longevity on male and female fitness in Hedychium villosum var
毛姜花原变种花寿命对两性适合度的影响
DOI:10.3773/j.issn.1005-264x.2009.01.010
[本文引用: 1]
植物的花寿命被认为是由雌、雄适合度的增长和维持花开放的花费之间的平衡来决定的。姜花属(Hedychium)是姜科唯一一个从热带到高海拔地区分布的大属, 属内不同种类植物的花寿命差异很大。毛姜花原变种(H. villosum var. villosum)的花寿命为5 d, 显著长于其它同域分布的姜科植物。通过人工剪除毛姜花原变种的柱头来使花朵具雌性功能的时间缩短, 结果显示: 在不同的处理中, 结实率随花朵具雌性功能时间的延长而增加, 开花1 d后剪除柱头的结实率为1.85% ± 1.59%, 极显著低于对照的结实率20.96% ± 4.13%, 说明其较长的花寿命能显著地增加传粉的成功率和结实率, 长达5 d的花寿命有利于雌性适合度的提高。同时, 毛姜花原变种开花1 d后, 剩余的平均花粉数和总平均花粉数没有显著差异, 而开花后2、3和4 d后剩余的平均花粉数则极显著少于总平均花粉数, 说明随着花寿命的延长, 花粉输出量也显著增加, 其长达5 d的花寿命也有利于其雄性适合度的提高。较长的花寿命在毛姜花原变种拓展新的生境、向更高海拔地区的扩散中也许起着重要的作用。姜科植物有着极其多样性的传粉和繁育系统, 花寿命在姜科植物传粉和繁育系统的多样性形成及其进化中起着重要作用, 同时, 较长的花寿命有效地提高了雌性适合度和雄性适合度, 从而使姜科植物能脱离热带生境, 向更高海拔的地区扩散, 花寿命在姜科植物从热带地区到高海拔地区的分布过程中也起着重要作用。
Interspecific variation in pollen- ovule ratio is negatively correlated with pollen transfer efficiency in a natural community
DOI:10.1111/plb.12151
PMID:24628937
[本文引用: 1]
The pollination efficiency hypothesis has long been proposed as an explanation for interspecific variation in pollen-ovule (P:O) ratios. However, no empirical study on P:O ratios has directly and quantitatively measured pollen transfer efficiency (PE). Here, we use a PE index, defined as the proportion of pollen grains removed from anthers that are subsequently deposited on conspecific stigmas, as a direct and quantitative measure of PE. We investigated P:O ratios, pollen removal and pollen deposition in 26 plant species in an alpine meadow, over three consecutive years. Our community survey showed that nearly 5% of removed pollen was successfully deposited on conspecific stigmas. The PE index ranged from 0.01% up to 78.56% among species, and correlated negatively with the P:O ratio across years. This correlation was not changed by controlling for phylogenetic relationships among species, suggesting that the interspecific variation in P:O ratios can be attributed to the probability of pollen grains reaching a stigma. The results indicate that the pollination efficiency hypothesis can help to explain interspecific variation in P:O ratios. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.
Darwin’s beautiful contrivances: evolutionary and functional evidence for flower adaptation
DOI:10.1111/j.1469-8137.2009.02914.x URL [本文引用: 1]
Flower closure in response to temperature and pollination in Gentiana straminea Maxim. (Gentianaceae), an alpine perennial in the Qinghai-Tibetan Plateau
DOI:10.1007/s00606-005-0345-1 URL [本文引用: 1]
Pollination ecology of Gentiana lawrencei var. farreri, a late-flowering Qinghai-Tibet Plateau species
DOI:10.3773/j.issn.1005-264x.2009.06.016
[本文引用: 2]
Aims Gentiana lawrencei var. farreri (Gentianaceae), a late-autumn or early-winter flowering alpine perennial, is distributed mainly in the northeastern Qinghai-Tibetan Plateau (QTP). The environment of the QTP is harsh because temperature is low and insects are scarce. Our aim is to examine the pollination ecology of G. lawrencei and its adaptive relationship with the environment. Methods The pollination ecology of G. lawrencei was documented for three consecutive years in northeastern QTP. The breeding system was tested and floral visitors were observed during the flower life span. Flower longevity was recorded and stigma receptivity was tested by the seed-set ratio of different days in which the stigma was presented. Important findings The seed-set of G. lawrencei under natural conditions was extremely low because of pollen-limitation. Combined characters of herkogamy and incomplete dichogamy indicate that pollinators are needed for complete pollination. Some individuals of G. lawrencei could produce seeds under bagging without emasculation, and it may be from selfing caused by thrips and ants. Bombus kashmirensisand B. sushikini are effective pollinators of G. lawrencei, but the frequencies of visits are extremely low (0.006 and 0.005 time·flower-1·h-1, respectively). Floral longevity and stigma receptivity are relatively long compared with other Gentianaceae species, and these increase the probability of pollination chances under low temperature and low pollinator conditions. The combination of self- and cross-pollination, as well as the prolonged floral longevity and stigma receptivity, may be the main reason for the survivorship of G. lawrencei.
青藏高原晚期开花植物线叶龙胆的传粉生态学
DOI:10.3773/j.issn.1005-264x.2009.06.016
[本文引用: 2]
线叶龙胆(Gentiana lawrencei var. farreri)主要分布在青藏高原, 在晚秋和早冬开花。为了探明线叶龙胆繁育系统特点, 探讨其对环境的繁殖适应特征, 对其传粉生态学过程进行了连续3年的观察。线叶龙胆自然状态下的结籽率很低, 存在严重的花粉限制。雌雄异位和不完全雌雄异熟的花特征表明其结实必须依赖昆虫传粉。繁育系统实验表明, 部分套袋花也能结实, 这可能主要是由蓟马(Thripidae spp.)和蚂蚁(Formica spp.)等小昆虫协助自交所致。克什米尔熊蜂(Bombus kashmirensis)和苏氏熊蜂(B. sushikini)是线叶龙胆的有效传粉昆虫, 但其访花频率非常低, 分别为0.006和0.005 time·flower<sup>-1</sup>·h<sup>-1</sup>。线叶龙胆花持续期和柱头可授能力都长于其他已报道的龙胆类植物, 从而在温度低、传粉昆虫少的情况下提供了更多传粉机会。线叶龙胆同时具有协助自交和杂交的繁殖现象, 以及较长的花持续期和柱头持续能力, 这可能是其在青藏高原地区赖以存活和延续的一个重要原因。
Advances in pollination biology
传粉生物学的研究进展
Modification of bumblebee behavior by flower color change and implications for pollen transfer in Weigela middendorffiana
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Temporal variation in flower display size and individual flower sex allocation in racemes of Narthecium asiaticum (Liliaceae)
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Flexible style that encourages outcrossing
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Adaptation of flower traits and mating system to pollinator unpredictibility: the case of Disterigma stereophyllum (Ericaceae) in southwestern Colombia
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Plant phenotypic plasticity in a changing climate
DOI:10.1016/j.tplants.2010.09.008
PMID:20970368
[本文引用: 1]
Climate change is altering the availability of resources and the conditions that are crucial to plant performance. One way plants will respond to these changes is through environmentally induced shifts in phenotype (phenotypic plasticity). Understanding plastic responses is crucial for predicting and managing the effects of climate change on native species as well as crop plants. Here, we provide a toolbox with definitions of key theoretical elements and a synthesis of the current understanding of the molecular and genetic mechanisms underlying plasticity relevant to climate change. By bringing ecological, evolutionary, physiological and molecular perspectives together, we hope to provide clear directives for future research and stimulate cross-disciplinary dialogue on the relevance of phenotypic plasticity under climate change.Copyright © 2010 Elsevier Ltd. All rights reserved.
Visual cues and foraging choices: bee visits to flower colour phases in Alkanna orientalis (Boraginaceae)
DOI:10.1111/j.1095-8312.2006.00582.x URL [本文引用: 1]
What explains the variation in length of stamens and styles in a pollen flower? A study exemplified by Macairea radula (Melastomataceae)
DOI:10.1007/s00606-021-01793-w URL [本文引用: 1]
How many flowering plants are pollinated by animals?
DOI:10.1111/j.1600-0706.2010.18644.x URL [本文引用: 1]
Plastic responses contribute to explaining altitudinal and temporal variation in potential flower longevity in high Andean Rhodolirion montanum
DOI:10.1371/journal.pone.0166350 [本文引用: 1]
Longevity of individual flowers
DOI:10.1146/annurev.es.16.110185.000311 URL [本文引用: 1]
Advancements in reproductive assurance and delayed selfing
繁殖保障和延迟自交的研究进展
Effect of climate change on the distribution and phenology of plants, insect pollinators, and their interactions
DOI:10.17520/biods.2020196
[本文引用: 1]
<p id="p00005"><strong>Aim:</strong> The impact of global climate change on ecosystems creates a pressing and significant challenge to society. Climate change is increasing the frequency and severity of extreme climate events, which have a direct impact on ecosystem productivity and service functions. Here, we conducted a literature review on research progress in this field, including analyses of interaction network structure, temporal and spatial distribution changes, and the importance of “rewiring” interactive relationships and functional traits. </p> <p id="p00010"><strong>Progress:</strong> Recent research has focused on the effects that increasing temperatures have on plant-pollinators in two primary ways. The first is the change in plant and pollinator distributions, including the potential for extirpation of some populations. The second is the change in plant and pollinator phenology, or the change in timing of plant flowering and pollinator activity. Spatial or temporal changes in plants and pollinators under climate change may cause mismatches and potential losses of current plant-pollinator relationships. In addition, climate change may alter the functional traits and coupling between plants and their pollinators, which could affect the stability of their interactions. </p> <p id="p00015"><strong>Outlook:</strong> We recommend that future research should increasingly focus on: (1) covering multiple scales of biodiversity, (2) long-term monitoring of plant-pollinator interaction networks, (3) measuring the fitness of important indicator species, (4) recording changes in the functional traits of plants and pollinators along spatial and temporal scales to help rewire and/or restore their interactions, and (5) evaluating the conservation status of key plants and their pollinators. </p>
气候变化对植物-传粉昆虫的分布区和物候及其互作关系的影响
DOI:10.17520/biods.2020196
[本文引用: 1]
全球气候变化对生态系统的影响是人类社会面临的紧迫而又严峻的挑战。气候变化带来的极端气候事件的增多, 直接影响到生态系统生产力和服务功能。本文总结了气候变化对植物-传粉昆虫互作的研究进展, 强调植物-传粉昆虫互作网络结构和其时空演变的解析, 以及互作关系和功能性状重组研究的重要性。近年来在气温持续上升背景下对植物-传粉昆虫互作关系影响的研究也受到了更多关注, 这些研究主要集中在两方面: 一是植物和传粉昆虫分布区的变化, 包括部分种群可能灭绝; 二是物候的变化, 即植物花期和传粉昆虫活动期的改变。植物与传粉昆虫任何一方在空间或时间上的改变, 都会导致传粉关系的错配或丢失。此外, 也可能导致植物-传粉昆虫双方的功能性状及其耦合的改变, 从而影响其互作关系的稳定。建议在今后的研究中关注: (1)覆盖生物多样性的多个尺度的研究; (2)对植物-传粉者互作网络的长期监测; (3)重要指示物种繁殖适合度评价; (4)植物-传粉昆虫互作双方功能性状在时间和空间尺度上的变化, 及其互作关系的重组; (5)关键植物和传粉昆虫类群的评估和保护。
Maintenance and functional gender specialization of flexistyly
DOI:10.3773/j.issn.1005-264x.2010.07.008
[本文引用: 1]
<FONT face=Verdana><EM>Aims</EM> In stylar polymorphous species, the morph ratios are maintained by negative frequency-dependent selection through disassortative mating. The spatial context of a population is of crucial importance to maintain this stylar polymorphism. Under particular circumstances, disassortative mating in such species may promote the evolution of a dimorphism by gender specialization. We asked whether flexistyly can promote sufficient disassortative mating, whether the female fitness of focal plant is affected by negative frequency-dependent selection at local level, and whether the two morphs in flexistylous plants differ in gender specialization.<BR><EM>Methods</EM> We used open-pollinated flexistylous <EM>Alpinia mutica</EM> to compare fertility in anaflexistylous, cataflexistylous and dimorphic arrays. Second, we used neighborhood models to investigate spatial distribution of morphs at local level within the population on reproductive output in the flexistylous, <EM>A. blepharaocalyx</EM>. We quantified the distribution of the morphs in terms of neighborhood morph bias. We then measured the effect of neighborhood<BR>morph bias on open-pollinated reproductive output. Third, the reproductive characters were examined in anaflexistylous and cataflexistylous morphs of <EM>A. blepharaocalyx</EM>. We assessed functional genders of two morphs based on their allocations associated with times-dependent mating opportunities and the mean number of seeds produced by anaflexistylous and cataflexistylous plants with morph frequency in the population.<BR><EM>Important findings</EM> Dimorphic arrays have higher female fertility than monomorphic arrays, demonstrating the flexistyly promotes inter-morph pollen transfer. Results from <EM>A. blepharaocalyx</EM> indicate that at the neighborhood scale, the two morphs have an aggregate distribution due to clonal growth. At this scale, focal plants showed no evidence of frequency-dependent total fruits and seeds per plant or seeds per flower. These results do not support frequency-dependent selection as a major mechanism affecting morph frequencies in <EM>A. blepharaocalyx</EM> within the context of this study. There are no significant differences between two morphs in flower and fruit characters. Functional gender analyses indicate that when illegitimate fertilization is negligible, the morphs are specialized in <FONT face=Verdana>their later sexual functions, mediated by anaflexistylous morph through male fitness gained; however, when selffertilization is included, the two morphs are both specialized in their female functions due to the lack of inbreeding depression in the formulas.</FONT></FONT>
花柱卷曲性的维持及功能性别特化
DOI:10.3773/j.issn.1005-264x.2010.07.008
[本文引用: 1]
花柱多态型的型比通过选型交配形成的负频率依赖的选择来维持。种群空间格局对于频率依赖选择所维持的花柱多态型是至关重要的。该研究使用摆放实验构建不同型比的马来良姜(Alpinia mutica)人工种群, 以评价花柱卷曲性促进选型交配的功能。使用邻域模型调查了云南草蔻(Alpinia blepharaocalyx)种群中的目标植株的坐果数、结籽数及其邻域中花序的数量和型偏以探讨在局域尺度上目标植株的雌性适合度是否受负频率依赖的选择。通过比较云南草蔻上举型和下垂型各繁殖性状的差异以及两型的功能性别的计算以评估两型功能性别可能存在的特化趋势。摆放实验结果说明花柱卷曲性形成的二型种群可以促进型间花粉传递。在局域尺度上, 云南草蔻两型倾向于同型聚集分布, 这一分布特点反映出其克隆生长特性。统计结果说明: 邻域中异型花粉供体相对丰富度对两型目标植株都无影响; 目标植株雌性适合度在邻域中不受负频率依赖选择的影响。这一结果并不支持负频率依赖的选择在该研究尺度上是影响种群型比结构的主要机制。云南草蔻两型个体在花期和果期的繁殖指标上不存在显著差异; 功能性别计算结果显示选型交配是种群内唯一的交配模式时, 下垂型功能性别偏雌性而上举型功能性别偏雄性。这一功能性别特化的趋势可能是通过对上举型的雄性功能的选择而造成的, 并可能与种群型结构相关。当功能性别计算只考虑自交而忽略近交衰退时, 种群功能性别偏向雌性。
Corolla wilting facilitates delayed autonomous self-pollination in Pedicularis dunniana (Orobanchaceae)
DOI:10.1007/s00606-004-0260-x URL [本文引用: 2]
Research progress on diversity and variation in flower color
DOI:10.3724/SP.J.1143.2012.12030 URL [本文引用: 1]
花色多样性与变异的研究进展
Extremely long-lived stigmas allow extended cross- pollination opportunities in a high Andean plant
DOI:10.1371/journal.pone.0019497 [本文引用: 1]
Variation in style length and the effect on reproductive success in Chinese plums
(Armeniaca mume).DOI:10.17520/biods.2018317 URL [本文引用: 1]
梅花个体内花柱长度的变异及其对繁殖成功的影响
DOI:10.17520/biods.2018317
[本文引用: 1]
植物个体内花型的变异影响繁殖成功, 雌性繁殖性状的变异可能影响雌性的繁殖成功, 也可能作为花粉的受体影响雄性的繁殖成功。然而, 植物个体内不同花柱长度的花产生的花粉是否影响植物的繁殖成功却少有研究。梅(Armeniaca mume)是原产我国的重要木本花卉和经济果树, 我们的野外观察发现在同一植株内, 不同花的花柱长度有变异, 存在长柱型、短柱型和雄花型(雌蕊败育)三种花型, 是比较雌性繁殖性状的变异对两性繁殖成功的影响的理想材料。本文主要测量了不同花型的花部特征, 统计花期, 并开展体外花粉萌发以及人工控制授粉实验。结果表明: 长柱型的花冠直径、雌蕊长、单花花粉数、花粉体积显著大于短柱型和雄花型。长柱型的单花期以及雌花期显著长于短柱型。长柱型、短柱型以及雄花型花粉在活体柱头上的萌发率没有显著性差异, 雄花型的花粉管长度显著高于长柱型和短柱型。长柱型为母本的花粉萌发率以及花粉管的长度要显著高于短柱型。长柱型、短柱型、雄花型花粉授粉与自然对照处理的坐果率没有显著性差异, 而长柱型为母本的坐果率要显著高于短柱型为母本的坐果率。这些结果表明野生梅花的长柱型为母本有利于花粉的萌发和花粉管的伸长, 有高的坐果率; 但其作为花粉供体的雄性功能与其他花型没有差异。
The avoidance of interference between the presentation of pollen and stigmas in angiosperms II. Herkogamy
DOI:10.1080/0028825X.1986.10409726 URL [本文引用: 2]
Functional morphology and wasp pollination of two south American asclepiads (Asclepiadoideae- Apocynaceae)
DOI:10.1093/aob/mcr268 URL [本文引用: 2]
Pollination ecology of alpine herb Meconopsis integrifolia at different altitudes
DOI:10.17521/cjpe.2015.0001 URL [本文引用: 1]
高山植物全缘叶绿绒蒿在不同海拔地区的传粉生态学研究
DOI:10.17521/cjpe.2015.0001
[本文引用: 1]
为了探明高山植物全缘叶绿绒蒿(Meconopsis integrifolia)的繁育系统特点和其对高山气候环境的繁殖适应特征, 我们沿海拔梯度选择了5个样地(样地1 (4452 m)、样地2 (4215 m)、样地3 (4081 m)、样地4 (3841 m)、样地5 (3681 m))对其传粉生态学进行了连续2年的观察试验。结果发现, 样地1、2的全缘叶绿绒蒿的单花寿命显著长于样地3、4和5。花开放早期柱头高于花药, 之后花药不断伸长, 并在开放中后期与柱头接触, 说明全缘叶绿绒蒿具有不完全雌雄异位的花部特征。自然状态下, 柱头可授能力持续期约8天(雌蕊先熟), 但花药于开花第5天才散粉, 花粉寿命约2天, 说明全缘叶绿绒蒿为雌雄异熟, 但存在一定的重叠期。人工授粉试验表明, 全缘叶绿绒蒿自交部分亲和, 且不存在无融合生殖现象。各样地中自然对照的结实率显著低于人工异交处理的结实率, 说明自然状态下全缘叶绿绒蒿存在一定程度的传粉限制。传粉昆虫观察发现, 样地1和2的传粉昆虫主要是蝇类, 样地3、4和5的传粉昆虫主要是蝇类和蓟马(Thripidae spp.), 蝇类在不同植株间的活动能够保证异花传粉结实, 同时, 蝇类和蓟马在花内的活动会引起“协助自交”。全缘叶绿绒蒿约65%的观察个体存在“自动自交”。蝇类在各样地的访花频率存在显著差异, 样地1访花频率最低, 样地2访花频率最高。各样地的结实由于异花传粉者的不足而受到传粉限制。两种不同类型的自交机制恰恰为该植物异花传粉者不足提供了一定程度的繁殖补偿。全缘叶绿绒蒿不分泌花蜜, 当环境温度降低时, 采取为昆虫提供保温庇护场所的方式来吸引传粉者。
Adaptive significance of yellow flowered Bombax ceiba (Malvaceae)
DOI:10.17520/biods.2019003 URL [本文引用: 1]
木棉黄花个体的适应意义
DOI:10.17520/biods.2019003
[本文引用: 1]
木棉(Bombax ceiba)花大、红色, 多为鸟媒传粉, 但也存在频率极低的黄花个体, 有蜜蜂访花。本文对比研究了海南岛木棉红花、黄花的花部特征及传粉过程, 以解释黄花个体的适应意义。木棉两种花色表型的花蜜组分(葡萄糖和果糖)及挥发性物质(烷烃类、酯类、酚类等)没有显著差异, 但黄花花瓣的反射波长范围均在鸟类与蜜蜂视觉范围内, 可同时吸引鸟和蜜蜂。木棉黄花的雌雄异熟程度较小(花粉活性时期与柱头可受期重叠较大), 可在传粉媒介访花次数有限的情况下同时输出或接受花粉。另一方面, 黄花有着更大程度的柱头探出式雌雄异位, 降低了较小程度雌雄异熟可能导致的自交与雌雄功能干扰。木棉存在明显的花粉限制, 且黄花的坐果率(1.08 ± 0.56)%显著低于红花(3.27 ± 0.93)%。我们推测, 黄花个体可能通过增加木棉访花者类群多样性、降低雌雄异熟程度而提高了木棉的繁殖成功率, 也通过吸引蜜蜂而降低了蜜蜂对红花鸟媒传粉的干扰。
Mating system evolution, resource allocation, and genetic diversity in plants
植物交配系统的进化、资源分配对策与遗传多样性
Flexistyly and its evolutionary ecological significance
花柱卷曲性异交机制及其进化生态学意义
有花植物具有纷繁复杂的繁育系统，以避免或促进自交或异交。花柱卷曲性异交机制(Flexistyly)是最近在热带山姜属(Alpinia)植物中发现的一种促进异交的行为机制。具有这一机制的种类其自然种群中的个体根据开花行为的不同分为两种表型：一种上午散发花粉而其柱头向上反卷，远离昆虫拜访的通道；另一种其柱头上午垂向唇瓣，能够接受拜访昆虫的传粉，但自身的花药却不打开。到中午时分，两种表型花通过互为相反的柱头卷曲运动转换性别——前者柱头向下卷曲，后者柱头向上卷曲且花药打开。每朵花的花期为12 h，两种表型在自然种
Review of evolutionary ecology of flower longevity
花寿命的进化生态学意义
DOI:10.3773/j.issn.1005-264x.2009.03.019
[本文引用: 1]
花寿命(Floral longevity)是指一朵花保持开放并具有功能的持续时间, 它作为一种重要的繁殖策略影响着植物的繁殖, 在植物繁殖策略的进化生态学研究中具有非常重要的意义。近年来, 进化生态学家开始重视花寿命的研究, 在传粉与非传粉因素对花寿命的影响、花展示和繁殖成功与花寿命的关系等方面取得了长足的进展。生活史进化模型表明, 最优花寿命取决于开花成本和两性适合度实现速率之间的权衡。大量的实验研究支持此模型。实验研究表明: 授粉可导致某些植物的花寿命显著缩短, 但是, 花粉移除对花寿命一般没有显著影响; 部分植物的花具有最短花寿命, 这可能是一种保证植物雄性适合度的机制; 温度和水分等非传粉因素的变化, 因改变开花成本而影响到花寿命; 在花的群体水平上, 植物根据传粉状况和资源状况, 会调节花序上不同花的开放时间, 进而改变花展示的结构和功能; 长的花寿命是保障植物繁殖成功的重要机制之一, 但可能要付出一定的适合度代价。该文概述了花寿命进化生态学的理论和实验研究进展, 最后指出: 在理论研究上, 雌雄利益冲突为理解花寿命的进化提供了新的视角。在实验研究中, 需要重视植物通过优化花寿命而增强雄性适合度的研究思路。对花寿命的成本-收益分析, 需要考虑单花与花展示的功能关系。
Spatiotemporal variation in the pollination systems of a supergeneralist plant: Is Angelica sylvestris (Apiaceae) locally adapted to its most effective pollinators?
DOI:10.1093/aob/mcy140 URL [本文引用: 2]
