NaCl胁迫对葡萄砧木光合特性与叶绿素荧光参数的影响

为探究葡萄（Vitis sp.）砧木对盐胁迫的响应机制，以耐盐葡萄砧木品种101-14M（V. riparia×V. rupestris）和盐敏感品种188-08（V. berlandieri × V. riparia）的一年生苗为试材，比较研究了0、4、6、8、10 g·kg-1的NaCl胁迫对2种砧木叶片叶绿素含量、光合气体交换参数和叶绿素荧光参数的影响。结果表明：随着盐浓度升高，净光合速率、气孔导度、胞间二氧化碳浓度和蒸腾速率显著下降，同时最大荧光产量、最大光化学效率、实际光化学效率和光化学淬灭系数也呈下降趋势，初始荧光产量、非光化学淬灭系数和叶绿素含量表现为先升高后降低。在6 g·kg-1 NaCl胁迫下，188-08光合速率降低主因由气孔限制转向叶绿素限制，并在8 g·kg-1 NaCl胁迫下PSⅡ受到严重损伤；而101-14M叶片在8 g·kg-1盐胁迫下主要因叶绿素限制造成光合受限，并在10 g·kg-1盐胁迫下PSⅡ反应中心遭受损伤。

Effects of NaCl Stress on Leaf Photosynthesis and Chlorophyll Fluorescence Parameters of Vitis sp. Rootstocks

In order to explore the response mechanism of grape (Vitis sp.) rootstocks to salt stress, one-year potted cuttings of 101-14M (V. riparia×V. rupestris, resistant to salt stress) and 188-08 (V. berlandieri × V. riparia, sensitive to salt stress) were irrigated with 0, 4, 6, 8 and 10 g·kg-1 of NaCl solution, and changes of chlorophyll content, photosynthetic gas exchange and chlorophyll fluorescence parameters were studied. The results showed that: with increasing NaCl concentration, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) decreased significantly, and the maximal fluorescence (Fm), potential photochemical efficiency of PSⅡ (Fv/Fm), maximum quanta yield (Yield) and photochemical quenching coefficient (qP) showed a decreasing trend , while instantaneous fluorescence emission (F0), non-photochemical quenching coefficient (NPQ) and chlorophyll content increased first and then decreased. These results demonstrated that the decrease of chlorophyll contents instead of stomatal limitation mainly caused photosynthesis reduction of 188-08 when NaCl concentration was 6 g·kg-1, and PSⅡ was impaired severely when NaCl concentration was 8 g·kg-1. However, chlorophyll restrictions mainly caused photosynthesis Ⅱ reduction of 101-14M when the concentration of NaCl reached to 8 g·kg-1, and PSⅡ damage of 101-14M occurred when concentration of NaCl came up to 10 g·kg-1.