薄叶兰对遮光与干旱胁迫的光合生理响应

发布时间：2019-06-22 17:01

【摘要】：本文以薄叶兰Lycaste macrobulbon为试验材料,通过叶绿素荧光参数的测定和叶绿素含量的测定,对薄叶兰不同光合器官光合特性作了研究;通过遮光试验测定气体交换参数和叶绿素荧光参数,研究了薄叶兰适宜的光照条件;通过干旱胁迫试验测定光合速率日变化、可滴定酸含量昼夜变化和气孔昼夜运动情况,研究了干旱胁迫对薄叶兰光合生理的影响。研究结果如下:(1)薄叶兰的光合器官叶片、假鳞茎、萼片均进行光合作用,萼片下表皮存在气孔,叶绿素荧光参数中有效光化学量子产量Y(Ⅱ)、电子传递速率ETR、最大光化学量子产量Fv/Fm的值叶片高于假鳞茎,假鳞茎高于萼片,表明叶片光合作用能力最大。薄叶兰假鳞茎的总叶绿素含量约为叶片17.9%,类胡萝卜素的含量为叶片的17.1%;萼片总叶绿素含量约为叶片的3.1%,类胡萝卜素的含量为叶片的13.2%。叶片Chla/Chlb值为2.258,假鳞茎C hla/Chlb值为2.231,萼片Chla/C hlb值为1.04。(2)薄叶兰光饱和点在400~500μmol·m~(-2)·s~(-1)处,光补偿点在0~20μmol·m~(-2)·s~(-1)处,光饱和点、光补偿点均较低。20%光照处理的气体交换参数曲线高于40%光照处理高于10%光照处理,说明薄叶兰在20%光照条件下光合能力最强。薄叶兰初始荧光F0、最大荧光Fm、最大光化学量子产量Fv/Fm的值三个光照处理差异不大,有效光化学量子产量Y(Ⅱ)、电子传递速率ETR、荧光淬灭qP的值40%光照处理高于20%光照处理高于10%光照处理。说明40%光照处理薄叶兰PSⅡ反应中心光合活性最强。(3)薄叶兰叶片净光合速率白天正值,夜间负值,干旱胁迫下净光合速率显著降低,最大值为0.859μmolCO2·m~(-2)·s~(-1),对照组最大值为3.789μmolCO2·m~(-2)·s~(-1);干旱胁迫下气孔导度值一直很低,在0~0.02mmolH2O·m~(-2)·s~(-1)之间,随时间变化气孔导度变化幅度不大,对照组薄叶兰叶片气孔导度随时间变化呈单峰型曲线,最大值0.088mmolH2O·m~(-2)·s~(-1)。薄叶兰叶片干旱胁迫组可滴定酸含量高于对照组,在白天的10:00与16:00无明显变化,夜间22:00明显降低,凌晨4:00又升高,而对照组叶片可滴定酸含量在日夜的四个时间点都无明显变化,叶片总有机酸含量含量夜间未出现明显增高,在干燥条件下诱导未有出现CAM植物酸代谢现象。薄叶兰两种处理气孔的开放率、长度、宽度、密度统计发现,两种处理气孔在白天和夜间均有不均匀关闭的现象,干旱胁迫组气孔体积小密度大,气孔开放率在10:00与22:00差异不明显,对照组气孔开放率昼夜变化较大。
[Abstract]:In this paper, the photosynthetic characteristics of different photosynthetic organs of Elaeagnus angustifolia Lycaste macrobulbon were studied by measuring chlorophyll fluorescence parameters and chlorophyll content, and the suitable light conditions were studied by measuring gas exchange parameters and chlorophyll fluorescence parameters by shading test. The diurnal variation of photosynthetic rate, diurnal variation of titratable acid content and diurnal movement of stomata were measured by drought stress experiment. The effects of drought stress on photosynthetic physiology of Elaeagnus angustifolia were studied. The results are as follows: (1) the photosynthetic organ leaves, pseudo-bulb and sepals of Elaeagnus angustifolia all carry out photosynthesis, there are stomata in the lower epidermis of sepals, the effective photochemical quantum yield Y (鈪，

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