摘要
烤烟成熟期净光合速率随烟叶部位的上升而增强,随成熟度的加深而降低。叶龄与净光合速率呈极显著负相关。光合产量为中部叶最大,中上部叶及中下部叶次之,上部叶最小;成熟过程中各部位叶的光合产量都下降,中下部叶下降得最快、最早,中部叶次之,中上部叶及上部叶升高后又下降,且下降得更晚些。成熟期各部位叶的光饱和点是760～1140μmolm^(-2)s^(-1),各部位叶的光补偿点为12～35μmolm^(-2)s^(-1),随烟叶部位及成熟度而异。这些光合生理特性的变化为确定烤烟最适采收期提供了理论依据。
The change of leaf age causes variation of some physiological characteristics of leaf at different stalk position during the maturity. The leaf—age is significantly negatively correlated with the net photosynthetic rate (Pn), the chlorophyll content, the stomatal conductance and the transpiration rate respectively and is positively correlated with the specific leaf weight and the stomatal resistance respectively with same significance.The Pn is influenced by many physiological factors. During the ripening process, the chlorophyll content, the stomatal conductance and the transpiration rate are positively correlated with Pn. The specific leaf weight and stomatal resistance are negatively correlated with Pn. The path coefficient analysis shows that the direct effect of chlorophyll content on Pn is the highest, with a direct path coefficient, 0.6332 The specific leaf weight, the stomatal conductance, the stomatal resistance and the transpiration rate show their effect on Pn indirectly by means of variation of chlorophyll content. The specific leaf weight also has indirect effect on Pn with the variation of stomatal conductance. The residue path coefficient is low, with a figure of 0.1943. So the chlorophyll content is the most important factor which shows its effect on the Pn. These data would be useful for the harvest and breeding of flue-cured tobacco.
关键词
烤烟
成熟期
光合作用
烟草
flue-cured tobacco
maturation phase
leafage
net photosynthetic rate.
