光强对苗期烤烟光合作用及干物质生产的影响

Effects of light intensity on photosynthesis and dry matter production of flue-cured tobacco at its seedling stage.

以烤烟云烟87为材料,研究了不同光照强度(100%、88%、72%、62%自然光强)对苗期烤烟光合作用及干物质生产的影响.结果表明:烟苗在晴天中午100%自然光强下会产生光合抑制现象,适度遮光(88%自然光强)会消除光抑制,其日光合总量显著高于其他处理.遮光降低了烟苗光饱和点和光补偿点,增加了表观量子效率和弱光时的净光合速率,提高了叶绿素a和叶绿素b含量,降低了叶绿素a/b和类胡萝卜素含量.在88%自然光强下,烟苗具有较高的光饱和点和较低的光补偿点,对光照变化的适应性较强,其光合同化潜力有所提高.100%自然光强处理更有利于干物质和可溶性总糖向茎部转移,88%自然光强处理更有利于干物质和可溶性总糖向根部转移.在本试验条件下,苗期适当遮光(88%自然光强)可以提高烟苗的成苗素质.

Taking flue-cured tobacco Yunyan 87 as test material,this paper studied its photosynthesis and dry matter production at seedling stage under 100%,88%,72%,and 62% natural light intensities.At noon of sunny days,100% natural light intensity inhibited the photosynthesis,while proper shading（88% natural light intensity） could eliminate the inhibition,and the daily photosynthesis was significantly higher than other treatments.Shading reduced the light saturation point and compensation point,enhanced the apparent quantum yield of photosynthesis and the net photosynthetic rate under weak light,increased the chlorophyll a and chlorophyll b contents,but decreased the chlorophyll a/b and cartenoids contents.Under 88% natural light intensity,tobacco seedlings had higher light saturation point,lower compensation point,higher suitability to the change of light intensity,and higher photosynthetic potentiality.100% natural light intensity was more advantageous to the transfer of dry matter and soluble sugar to stem,while 88% natural light intensity was more beneficial to the transfer of dry matter and soluble sugar to root.Under the conditions of this experiment,proper shading（88% natural light intensity treatment） could improve the seedling quality of flue-cured tobacco.