水分对柠条萌蘖株和未平茬株光合参数及调渗物质的影响

对柠条Caragana korshinskii平茬后的萌蘖株和未平茬的对照株在夏季旺盛生长期进行了水分处理，并研究了浇水前后萌蘖株和对照株光合参数及调渗物质的变化。浇水前,萌蘖株具有较高的水势 (LWP)、光合速率(A)、气孔导度(G)、蒸腾速率(E)、光系统II最大光化学量子效率(Fv/Fm)和光系统II实际量子产率(△F/Fm′)；而对照株相应指标较低，但对照株光化学猝灭系数（NPQ），脯氨酸(Pro)、 丙二醛(MDA)含量较高。浇水后，对照株LWP、A、G、E、Fv/Fm、△F/Fm′均有不同程度的上升，而NPQ值和Pro、MAD的含量下降。浇水对萌蘖株和对照株叶绿素(Chla+b)含量影响不显著，且浇水前后萌蘖株均高于对照株。结果表明：萌蘖株在生长季所受干旱胁迫较小，植物将更多的光能以光合作用的形式利用，植物生长迅速；而对照株所受干旱胁迫的影响较为严重，光合速率低，植物将更多的光能以热的形式消耗，导致植物生长缓慢。

Effect of water on photosynthetic parameters and osmotic solute of sprouting and its intact plants of Caragna korshinskii

Water treatments were carried out to the sprouting plants (damaged plants) and its undamaged plants of Caragana korshinskii in growing period in summer. The aim was to investigate photosynthetic parameters and osmotic solutes of sprouting plants and its undamaged plants before and after watering. Before watering, the sprouting plants had higher water potential (LWP), higher photosynthetic rate (A), higher stomatal conductance (G), higher transpiration rate (E), higher photochemical efficiency of photosystem II (PSII) (△F/Fm′) and the maximum quantum efficiency of PSII photochemistry (Fv/Fm), whereas undamaged shrubs had lower corresponding indexes, and had higher non photochemical quenching of chlorophyll fluorescence (NPQ), higher proline (Pro) and higher malondialdehyde (MDA) content. After watering, parameters were different between sprouting and undamaged shrubs. Parameters including LWP, A, G, E, Fv/Fm, △F/Fm′ of undamaged shrubs were all increased, while the values of NPQ and the contents of Pro as well as MDA were decreased. The content of chlorophyll a and b within sprouting plants was higher than that of it within its undamaged plants before and after watering between treatments, but did not vary significantly with water available. It was concluded that the sprouting plants had less drought stress at growing season and had higher photosynthetic efficiency by use of solar energy in photosynthesis, which resulted in a quick growth. Undamaged shrubs had lower photosynthetic efficiency under stressful conditions, which dissipated much solar energy to space by means of heat, and as a result, the growth decreased.