Department of Plant Biology and Ecology, University of Seville, 41080 Seville, Spain.
Physiol Plant. 2010 Sep 1;140(1):32-45. doi: 10.1111/j.1399-3054.2010.01382.x. Epub 2010 May 7.
Gender-specific requirements of reproduction in dioecious species can lead to different physiological responses in male and female plants, made in relation to environmental constraints, and influencing growth, survival and population structure. Gender-related physiological differences and seasonal responses, indicating the existence of compensatory mechanisms of reproduction, were examined during a drought year in the dioecious shrub species Corema album. To integrate aboveground and belowground physiological responses, chlorophyll fluorescence, leaf gas exchange, water potential and xylem water isotopic composition were monitored throughout the diurnal cycle and annual phenological sequence of the species. Sampling was carried out in Doñana Natural Park (SW Spain) in Mediterranean-type climate conditions. The gender which bore greater reproductive effort showed higher physiological stress. Intersexual differences in leaf water potential were interpreted as arising from each gender's maximum reproductive allocation; lower values were found during flowering in males and during fruit production in females. Cold temperatures during winter fostered photoinhibitory responses that were most evident in male individuals, as a response to their relatively higher investment in reproduction during flowering. Net assimilation rate was not influenced by reproductive status; however, females tended to show higher values of this parameter at midday. The integrated analysis of photosynthetic variables and water relations indicated a gender effect in the physiological response at midday. The oxygen isotopic composition of xylem water showed a lack of dependence on the water table during the drought period, and indicated intersexual differences in water catchment. Females reached deeper soil layers, suggesting mechanisms compensating for their higher reproductive effort, and giving new evidence of physiological gender dimorphism in the belowground responses of a woody species.
雌雄异株物种的生殖的性别特异性要求可能导致雌雄植物在生理上产生不同的反应，这些反应是与环境限制有关的，并影响生长、存活和种群结构。在两性灌木物种 Corema album 的干旱年份中，研究了与性别相关的生理差异和季节性反应，表明存在生殖的补偿机制。为了整合地上和地下的生理反应，在整个日周期和物种的年物候序列中监测了叶绿素荧光、叶片气体交换、水势和木质部水同位素组成。采样在西班牙西南部地中海气候条件下的多纳纳自然公园进行。生殖投入较大的性别表现出更高的生理压力。叶水势的雌雄间差异可以解释为每个性别最大生殖分配的结果；在雄性的开花期和雌性的果实生产期发现了较低的值。冬季的低温促进了光抑制反应，在雄性个体中最为明显，这是对它们在开花期相对较高的生殖投资的反应。净同化率不受生殖状态的影响；然而，女性在中午时往往表现出更高的该参数值。光合变量和水分关系的综合分析表明，在中午，生理反应存在性别效应。木质部水的氧同位素组成在干旱期间与地下水位无关，并且表明在水分收集方面存在雌雄间差异。雌性到达更深的土壤层，这表明了补偿其更高生殖投入的机制，并为木本物种地下反应中的生理性别二态性提供了新的证据。
