酸枣幼苗光合特征和生理生化指标对不同强度干旱胁迫的响应

Photosynthetic characteristics and physiological and biochemical indexes in response to drought stress in Zizyphus jujuba seedlings

文中以1a生酸枣幼苗为材料,采用盆栽控水试验,研究了干旱胁迫对酸枣幼苗的生长、生物量分配、光合色素、渗透调节物质等的影响。结果表明:1)在干旱胁迫下酸枣生长减缓,生物量积累逐步减小,生物量优先向根系分配,根冠比显著增大;2)干旱胁迫抑制了光合色素合成,且叶绿素a对干旱胁迫的反应比叶绿素b敏感;3)酸枣叶片的净光合速率(Pn)、气孔导度(Gs)以及蒸腾速率(Tr)呈现下降趋势,但胞间二氧化碳浓度(Ci)在逐渐上升,净光合速率的下降是由非气孔限制因素引起的;4)随着干旱胁迫强度的增加,游离脯氨酸(Pro)含量、丙二醛(MDA)含量和可溶性还原糖(SS)含量均呈现增加趋势,增加的相对幅度为Pro>SS>MDA。总体研究结果证明:干旱胁迫下酸枣幼苗的生长受到一定程度的抑制,但它们均能调节自身的叶绿物质含量和渗透调节物质等一系列生理学指标主动适应干旱逆境,表现出较强的抗旱能力。

By using 1 year old Zizyphus jujuba seedlings as material,pot water control experiment was conducted to probe drought stress effects on growth,biomass allocation,photosynthetic pigment,osmotic regulation substances and so on in Zizyphus jujuba seedlings. Results show that：（ 1） Under the drought stress,the growth of Z. jujuba slowed,biomass accumulation reduced gradually. The biomass was preferred to distribute to the root system,and the root-shoot ratio increased significantly.（ 2） Drought stress inhibited the photosynthetic pigment synthesis,and chlorophyll a was sensitive to drought stress than chlorophyll b.（ 3） Leaf net photosynthetic rate（ Pn）,stomatal conductance（ Gs）,and transpiration rate（ Tr） of Z. jujuba showed a decline trend,but the intercellular CO2 concentration（ Ci） gradually rose. Net photosynthetic rate decline was caused by other factors rather than stomatal limitation.（ 4） With the increase of drought stress intensity,free proline（ Pro） content,malondialdehyde（ MDA） content and the content of soluble reducing sugar（ SS） all showed increasing trend; the increase of relative amplitude was Pro〉 SS 〉MDA. Research results show that the growth of Z. jujuba seedlings was inhibited in a certain degree under drought stress,but they all could adjust its a series of physiological indexes to adapt to drought stress,showing a strong ability of drought resistance.