两种不同生境条件下软枣猕猴桃光合特性的比较

Photosynthetic Characteristics of Kiwiberry(Actinidia arguta)in Two Different Habitats

以林下、露地2种生境条件下栽培的三年生‘龙城2号’软枣猕猴桃为试材,利用Li-6400便携式光合仪测定两地软枣猕猴桃夏季光响应曲线及光合速率日变化,并分析各环境、生理因子对软枣猕猴桃净光合速率(Pn)的影响,探究了林下、露地2种生境条件下软枣猕猴桃光合特性差异及其影响因子,以期为软枣猕猴桃生产栽培过程中立地环境选择以及管理措施提供参考依据。结果表明:1)除表观量子效率(AQY)外,林下栽培软枣猕猴桃最大净光合速率(Pn_(max))、光补偿点(LCP)、光饱和点(LSP)均低于露地栽培软枣猕猴桃。2)露地栽培软枣猕猴桃一天中各个时刻的净光合速率均高于林下软枣猕猴桃,林下和露地生境下软枣猕猴桃“午休”分别是由非气孔因素及气孔因素引起的。3)林下软枣猕猴桃Pn与光合有效辐射(PAR)、气孔导度(Gs)、蒸腾速率(Tr)呈现极显著正相关(相关系数分别为0.713、0.543、0.497),与胞间二氧化碳浓度(Ci)呈现极显著负相关(-0.858)。露地软枣猕猴桃Pn与大气二氧化碳浓度(Ca)、相对湿度(RH)、气孔导度(Gs)呈现极显著正相关(0.440、0.405、0.696),与气温(Ta)极显著负相关(-0.459)。林下软枣猕猴桃对弱光的利用和转化能力高于露地软枣猕猴桃,但对强光利用能力弱于露地软枣猕猴桃。一天中露地栽培软枣猕猴桃具有更强的净光合能力。郁闭度>0.6的林下栽培环境下软枣猕猴桃光合能力主要限制因素是光照较弱,露地栽培环境下主要限制因素是高温及强光。

Three-year-old‘Longcheng 2’kiwiberry cultivated under the forest and in the open field were taken as materials,the light response curve of net photosynthetic rate(Pn)and the diurnal variation of Pn were measured by Li-6400(Licor,Lincoln,USA)portable photosynthetic apparatus.The photosynthetic characteristics and its influencing factors of kiwiberry cultivated in different habitats were analyzed in order to provide a reference for environment condition selection and management in the production and cultivation.The results showed that,1)except for the apparent quantum efficiency(AQY),kiwiberry cultivated in the open field had higher maximum net photosynthetic efficiency(Pn_(max)),light compensation point(LCP)and light saturation point(LSP)than those cultivated under the forest.2)Pn of kiwiberry cultivated in the open field was higher than that of kiwiberry under the forest at all times of day.The decrease in Pn of kiwiberry cultivated under the forest during midday was resulted from non-stomatal limitation,but stomatal limitation occurred in Pn of kiwiberry cultivated in the open field.3)Pn of kiwiberry cultivated under the forest was significantly positively correlated with photosynthetically active radiation(PAR),stomatal conductance(Gs)and transpiration rate(Tr)(correlation coefficients were 0.713,0.543,0.497),and negatively correlated with intercellular carbon dioxide concentration(Ci)(-0.858).Pn of kiwiberry cultivated in the open field was significantly positively correlated with atmospheric carbon dioxide concentration(Ca),relative humidity(RH)and stomatal conductance(Gs)(0.440,0.405,0.696),and negatively correlated with air temperature(Ta)(-0.459).The kiwiberry cultivated under forest had higher low-light utilization and conversion ability but lower high-light utilization ability than those in open field.During the whole day,the kiwiberry cultivated in open field had stronger photosynthetic capacity.The main problem in under-forest cultivation environment was weak illumination;the problems in open field cultivation environment were strong illumination and high temperature.