Xu Xiao, Yang Fan, Xiao Xiangwen, Zhang Sheng, Korpelainen Helena, Li Chunyang
Chengdu Institute of Biology, Chinese Academy of Sciences, PO Box 416, Chengdu 610041, China.
Plant Cell Environ. 2008 Jun;31(6):850-60. doi: 10.1111/j.1365-3040.2008.01799.x. Epub 2008 Feb 13.
Dioecious plant species represent an important component of terrestrial ecosystems. Yet, little is known about sex-specific responses to drought and elevated temperatures. Populus cathayana Rehd, which is a dioecious, deciduous tree species, widely distributed in the northern, central and southwestern regions of China, was employed as a model species in our study. In closed-top chamber experiments, sex-specific morphological, physiological and biochemical responses of P. cathayana to drought and different elevated temperatures were investigated. Compared with the controls, drought significantly decreased the growth and the net photosynthesis rate (A), and increased the intrinsic water use efficiency (WUE(i)), carbon isotope composition (delta13C), and the malondialdehyde (MDA) and abscisic acid (ABA) contents in droughted plants. In contrast, elevated temperatures significantly promoted the growth and the A, but decreased the WUE(i), delta13C, MDA and ABA contents in well-watered individuals. When compared with males, elevated temperatures induced well-watered females to express a greater increase in the height growth (HG), basal diameter (BD), leaf area (LA), total number of leaves (TNL), dry matter accumulation (DMA) and specific leaf area (SLA), and a lower decrease in the A value, transpiration (E), stomatal conductance (g(s)), MDA and ABA contents, while elevated temperatures induced drought-stressed females to exhibit lower values of HG, BD, LA, TNL, DMA, A, E, g(s) and the intercellular CO2 concentration (C(i)), and higher levels of SLA, WUE(i), delta13C, MDA and ABA contents. Our results indicated that the female individuals of P. cathayana are more responsive and suffer from greater negative effects than do males when grown under environments with increased drought stress and elevated temperature.
雌雄异株植物物种是陆地生态系统的重要组成部分。然而，关于干旱和气温升高的性别特异性响应，我们知之甚少。本研究以广泛分布于中国北方、中部和西南部地区的雌雄异株落叶乔木毛果杨（Populus cathayana Rehd）为模式物种。在封闭式气室实验中，研究了毛果杨对干旱和不同升高温度的性别特异性形态、生理和生化响应。与对照相比，干旱显著降低了生长和净光合速率（A），并提高了干旱处理植株的内在水分利用效率（WUE(i)）、碳同位素组成（δ13C）、丙二醛（MDA）和脱落酸（ABA）含量。相反，气温升高显著促进了充分浇水个体的生长和A，但降低了WUE(i)、δ13C、MDA和ABA含量。与雄性相比，气温升高使充分浇水的雌性在树高生长（HG）、基径（BD）、叶面积（LA）、总叶数（TNL）、干物质积累（DMA）和比叶面积（SLA）方面表现出更大的增加，而A值、蒸腾速率（E）、气孔导度（gs）、MDA和ABA含量的降低幅度较小；气温升高使干旱胁迫的雌性在HG、BD、LA、TNL、DMA、A、E、gs和胞间CO2浓度（Ci）方面表现出较低的值，而SLA、WUE(i)、δ13C、MDA和ABA含量较高。我们的结果表明，在干旱胁迫加剧和温度升高的环境中生长时，毛果杨的雌性个体比雄性个体更敏感，受到的负面影响更大。
