遮光对野鸦椿幼苗生长和光合生理特性的影响

为了解不同光照条件下野鸦椿幼苗的生长发育状况和光合生理特性,探讨野鸦椿幼苗生长发育的最佳光照条件。采用遮光方式模拟不同光照强度(全光照,遮光30%、60%和90%),研究野鸦椿幼苗的生长、生物量、光合色素含量、生理指标和光合日变化等光合特性的响应规律。结果表明:随着遮光程度的增加,野鸦椿幼苗的生长量均高于对照,以遮光60%的苗高、地径、根长、根幅的增幅最大;遮光30%、60%处理下其生物量积累较多,植株长势良好,叶色较深;遮光处理后,野鸦椿幼苗的叶绿素a、叶绿素b及叶绿素总量(Chla+Chlb)的含量增加,叶绿素a/b值降低;遮光处理使野鸦椿幼苗叶片可溶性蛋白含量降低,使叶片可溶性糖含量增加;遮光30%、60%处理条件下,叶片中MDA的含量显著低于全光照和遮光90%;随着遮光程度的加强,光合速率不断下降,以遮光30%处理下光合速率较高。因此,在育苗生产中,建议有效辐射强度保持在遮光率为30%~60%的范围,可培育出优良健壮的野鸦椿苗木。

Effects of Shading on Growth and Photosynthetic Characteristics of Euscaphis japonica Seedlings

This study aimed to understand the growth and photosynthetic characteristics of Euscaphis japonica seedlings under different light conditions and explored the best linght conditions for the growth and development of E.aponica seedlings.Shading method was used to simulate different light intensities〔full sunlight(CK),Shading rate 30%(A),60%(B),and 90%(C)〕and growth,biomass,chlorophyll content,photosynthetic characteristics,physiological indexes and diurnal changes photosynthesis of seedlings were analyzed.The results showed that with the increase of shading degree,the growth amount of E.aponica was higher than that of the control group,and 60%of the seedling height,ground diameter,root length and root amplitude increased the most.More biomass was accumulated and the plants grew well under the treatment of 30%and 60%shading.After shading,E.aponica seedlings chlorophyll a,chlorophyll b,total chlorophyll(Chla+Chlb)increased,the value of chlorophyll a/b decreased.Shading to make E.aponica of soluble protein content decreased,soluble sugar content increased;Under 30%and 60%shading conditions,the content of MDA in leaves was lower than that full sunlight and 90%shading;The photosynthetic rate decreased continuously with increasing shading,and the photosynthetic rate was high under 30%shading treatment.In seedling production,the suggested shading is 30%-60%.