羌活光合作用日变化及其与生理生态因子的关系

以大田引种栽培的羌活植株为材料,用Li-6400便携式光合作用测定系统原位测定自然条件下生长的羌活孕蕾期叶片的光合速率光响应、净光合速率及生理生态因子日变化,并通过相关分析、通径分析和逐步回归分析探讨净光合速率与生理生态因子的关系.结果表明:(1)羌活净光合速率(P_n)、 蒸腾速率(T_r)、气孔导度(G_s)日变化均呈双峰曲线,其净光合速率具有典型的"午休"现象,并主要由非气孔限制因素造成;(2)影响羌活叶片Pn日变化的主要决定生理因子是G_s,主要限制因子是胞间CO_2浓度(C_i);主要决定生态因子是空气相对湿度(RH),限制因子是气温(T_a); G_s是影响净光合速率最重要的生理生态因子.研究发现,羌活有较强的适应弱光环境的能力,属于阳性耐荫植物,宜选择海拔和荫蔽度均较高的环境进行引种驯化栽培,以利于其生长和存活.

Diurnal Variation of Photosynthesis and Relationship with the Eco-physiological Factors of Notopterygium incisum

The response of photosynthetic rate to photosynthetic effective radiation,diurnal change of photosynthetic rate and eco-physiology factors,were analyzed in situ by Li-6400 Portable Photosynthesis Analysis System under natural conditions,relative analysis,path coefficient analysis and stepwise regression equation were used to discuss how related factors influenced diurnal changes of photosynthetic rate.The results showed:(1)The diurnal variation of P_n ,T_r,G_s and PAR varied in a double-peaks curve.There was obvious midday depression of photosynthesis,because of the non-stomata limitation;(2)The main physiological factor affecting the characteristic of P_n of N.incisum was G_s,C_i was the main limiting factor;and the main ecological factor was RH,T_a was the limiting factor,and G_s was the key factor which affected P_n;The results indicated that N.incisum adapt strongly to week light capability.It is a heliophilous plant with strong shade-tolerance,while the higher elevation and shading habitats be suitable to the cultivation of N.incisum in order to grow and survive.