不同种植密度对杜仲生物量及光合生理特性的影响

Effects of Different Planting Densities on Biomass and Photosynthetic Physiological Characteristics of Eucommia ulmoides Oliver

以药用植物杜仲为材料,在3个种植密度D1(3000株/hm 2)、D2(6000株/hm 2)、D3(9000株/hm 2)水平下测定了杜仲的生长指标、气体交换参数、叶绿素荧光参数、光合色素含量及次生代谢产物含量,探讨密度对杜仲生长及光合生理的影响。结果表明,随着种植密度的增加,杜仲株高显著下降,单株叶片数量、叶面积、叶厚、干物质积累量和含水量均在D2处理组(6000株/hm 2)达到最高;气体交换参数随密度增加呈显著下降趋势;种植密度对杜仲叶片最大光化学效率Fv/Fm无显著影响(P>0.05),而PSⅡ实际光化学效率Φ(Ⅱ)和电子传递速率ETR随种植密度的增加显著降低,非光化学淬灭系数NPQ显著上升,光化学淬灭系数q P显著下降,说明种植密度与光合作用呈显著负相关;叶片叶绿素含量在D2处理组达到最高水平;次生代谢产物在D2和D3处理组含量最高(P<0.05)。因此,杜仲种植密度对不同的生长光合生理指标影响不同,在6000株/hm 2种植条件下,杜仲叶片保持良好的受光面积,水分和养分吸收充分,光合色素含量最高,干物质积累量最多。

The medicinal plant Eucommia ulmoides Oliver as the research object,the growth indexes,gas exchange parameters,chlorophyll fluorescence parameters,photosynthetic pigment contents and secondary metabolite contents of Eucommia ulmoides were measured at three planting densities of D1(3000 plants/hm 2),D2(6000 plants/hm 2)and D3(9000 plants/hm 2).The results showed that with the increase of planting density,the plant height of Eucommia ulmoides decreased significantly,the number of leaves per plant,leaf area,leaf thickness,dry matter accumulation and water content reached the highest in D2 treatment group of 6000 plants/hm 2;gas exchange parameters decreased significantly with the increase of density;planting density had no significant effect on the maximum photochemical efficiency(F v/F m)of Eucommia ulmoides leaves(P>0.05),but PS had no significant effect on PS The results showed that the actual photochemical efficiencyΦ(Ⅱ)and electron transfer rate ETR decreased significantly with the increase of planting density,the non photochemical quenching coefficient NPQ increased significantly,and the photochemical quenching coefficient q P decreased significantly,indicating that there was a significant negative correlation between plant density and photosynthesis;the chlorophyll content of leaves reached the highest level in D2 treatment group;the contents of secondary metabolites was the highest in D2 and D3 treatment groups(P<0.05).Therefore,the planting density of Eucommia ulmoides had different effects on different growth and photosynthetic physiological indexes.Under the planting conditions of 6000 plants/hm 2,Eucommia ulmoides leaves maintained a good light receiving area,fully absorbed water and nutrients,the highest photosynthetic pigment content and the most dry matter accumulation.This study provides an important reference for the cultivation of Eucommia ulmoides.