水分胁迫对夏蜡梅气孔行为的影响

了解干旱对夏蜡梅光合作用的影响状况,为夏蜡梅的保护和培育提供理论依据,以盆栽2年生夏蜡梅幼苗为材料,分对照、轻度、中度、重度4组,研究了土壤水分胁迫下气孔导度的变化.结果表明:随着水分胁迫的加重,净光合速率、蒸腾速率和气孔导度降低;夏蜡梅气孔导度日变化曲线由双峰型逐渐转变为峰值很小的单峰型,与净光合速率有较好的相关性.重度水分胁迫下气孔限制和非气孔限制(为主)引起夏蜡梅净光合速率成倍降低,严重影响其生长.

Effect of Water Stress on Stomatal Behavior of Sinocalycanthus chinensis Leaves

The objectives of the study were to define the effect of drought on photosynthesis and in theory to provide a scientific basis for conservation and cultivation of Sinocalycanthus chinensis,an endangered species in China.The changes of stomatal conductance(Gs) under four water conditions were investigated by using 2-year-old pot-cultured S.chinensis seedlings as experimental materials.Twelve pots of the plant seedlings with a similar growth were divided into 4 groups(no stress,mild stress,moderate stress and severe stress).The results showed as follows.With increases in water stress,some photosynthetic parameters reduced,including net photosynthetic rate(Pn),transpiration rate(Tr) and Gs.Moreover,the diurnal variation pattern of Gs shifted from a double-peaked curve gradually to a single-peaked one,exhibiting a closer relation of Gs to Pn.Gemination reduce of Pn may be attributed to non-stomatal limitation predominatingly and stomatal limitation secondarily under the heavy stress,brought out a strong growth inhibition of S.chinensis.