文冠果对干旱胁迫的光合生理响应

摘要

通过盆栽试验，以抗旱性强弱不同的两个种源地文冠果为试验材料，对干旱胁迫下文冠果的光合生理指标进行较为系统的研究，结果表明：①干旱胁迫条件下两个种源地文冠果叶片净光合速率（Pn）、气孔导度（Cond）、蒸腾速率（Tr）、叶绿素含量（Chl）都有不同幅度的下降。抗旱性强的文冠果（新疆喀什）随着干旱胁迫的加剧，净光合速率、气孔导度和叶绿素含量下降较慢。②轻度干旱胁迫下气孔限制是影响两个种源地文冠果 Pn下降的主要因素；中度和重度干旱胁迫下，非气孔限制是两个种源地文冠果 Pn下降的主要因素。③叶绿素荧光参数研究表明：干旱胁迫条件下两个种源地文冠果PSⅡ反应中心光化学效率（Fv/Fm ）、PSⅡ潜在活性（Fv/Fo ）均降低；PSⅡ光化学淬灭系数（qP）均降低，而PSⅡ非光化学淬灭系数（qNP）则增大。总体上，与抗旱性弱的文冠果相比，抗旱性强的文冠果的 Fv/Fm和Fv/Fo下降幅度较小，PSⅡ的光化学能力和PSⅡ潜在活性均较强；PSⅡ光化学淬灭系数（qP）降低的幅度较小且PSⅡ非光化学淬灭系数（qNP）降低幅度较大。%A pot-cultivation experiment was performed to investigate the photosynthetic physiology of X .sorbifolia under the drought stress .Two varieties of X .sorbifolia from different provenances were used to systematically study the phtotosynthetic physiology under the drought stress .The results showed that:(1)Under the drought stress,the net pho-tosynthetic rate,stomatal conductance,transpiration rate and chlorophyll content decreased in varying degrees both in the leaves of X .sorbifolia Compared to X .sorbifolia from Yan′an,Shaanxi with the low drought-resistance,the net photo-synthetic rate,stomatal conductance,transpiration rate and chlorophyll content decreased more slowly .In the leaves of X .sorbifolia from Kaishi,Xinjiang with high drought-resistance .(2)Under the light drought stress,stomatal restriction was the main factor for the Pn’s decreased in the leaves of both the two varieties of X.sorbifolia,while the non-stomatal restriction was the main factor for the Pn’decrease under the medium and severe drought stress.(3)The result of fluo-rescence experiment of PSⅡ Reaction Center indicated Fv/Fm and Fv/Fo decreased in both X .sorbifolia under the drought stress,the quenching of chlorophyll fluorescence (qP)decreased,and non-photochemical quenching of chloro-phyll fluorescence(qNP)increased for both X .sorbifolia under the drought stress .In general,compared to X .sorbifolia with the low drought-resistance,Fv/Fm and Fv/Fo had a smaller decrease,qP had a smaller decrease and qNP had a bigger increase in the leaves of X .sorbifolia under the drought stress .