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红皮柳(Salix purpurea)是我国西北地区重要的乡土树种,生长快、适应性强,在水土保持、防护林和生物质能源等方面发挥重要作用。以红皮柳扦插苗为研究材料,通过盆栽试验,在4种不同程度干旱胁迫处理(对照、轻度干旱、中度干旱和重度干旱胁迫)下,测定叶片的光合作用参数及生长量,分析探讨干旱胁迫对红皮柳光合特性及生长的影响。结果表明:在轻度、中度和重度干旱胁迫下,红皮柳叶片净光合速率(Pn)日均值分别比对照下降10.4%(P>0.05)、17.9%(P<0.05)和58.2%(P<0.05),中度和重度干旱胁迫下Pn下降量达到显著水平;随着干旱胁迫程度的加剧,Pn的下降伴随着蒸腾速率(Tr)和气孔导度(Gs)的显著下降,水分利用效率(EWUE)逐渐升高,胞间CO_2浓度(Ci)先下降后上升;轻度干旱胁迫和中度干旱胁迫下Pn的降低是由于气孔限制引起,而重度干旱胁迫下受到气孔因素与非气孔因素的共同作用。而且,红皮柳生长受到干旱胁迫的显著影响,随着干旱胁迫程度的加重,株高和基径的相对增长率下降程度增大。
Salix purpurea is an important indigenous tree species in Northwest China. It grows rapidly and adapts well and plays an important role in soil and water conservation, shelterbelts and biomass energy. The experiment was conducted in the pot experiment to measure the photosynthesis parameters and growth of leaves under different degrees of drought stress (control, mild drought, moderate drought and severe drought stress) Effects of Drought Stress on Photosynthetic Characteristics and Growth of. The results showed that the average daily net photosynthetic rate (Pn) of Malus ostiutus decreased by 10.4% (P> 0.05), 17.9% (P <0.05) and 58.2% (P <0.05) under mild, moderate and severe drought stress P <0.05). Under the moderate and severe drought stress, the decrease of Pn reached a significant level. With the aggravation of drought stress, the decline of Pn was accompanied by a significant decrease of transpiration rate (Tr) and stomatal conductance (Gs) (EWUE) increased gradually and the intercellular CO_2 concentration (Ci) decreased first and then increased. The decrease of Pn under mild drought stress and moderate drought stress was caused by stomatal limitation, while the stomatal factors and non-stomata were affected by severe drought stress The commonalities of factors. Moreover, the growth of T. australis was significantly affected by drought stress. With the aggravation of drought stress, the relative growth rate of plant height and base diameter decreased.