遮阴对凤丹生物量分配和化学计量特征的影响

Effects of Shading on Biomass and Stoichiometry of Fengdan

以安徽铜陵4年生凤丹人工林为对象,在不同遮阴处理(100%光照,CK;63%的光照,L63;34%的光照,L34)下,分析了凤丹的生物量和化学计量特征的变化,探讨凤丹生物量和化学计量特征对光照强度变化的响应。结果显示:与CK相比,经L63处理后凤丹的总生物量和茎生物量下降但叶片和果实生物量分别增加10.75%和335.69%;经L34处理后,总生物量及各构件生物量降低,但根、叶和果实生物量分配上升。遮阴处理显著增加凤丹整株的全C、全N和全K质量分数,全P在L63处理中质量分数上升、L34处理中降低;L64处理下质量分数(w)w(C)∶w(N)和w(C)∶w(P)显著降低,经L34处理的w(C)∶w(P)增加,而w(N)∶w(P)则随着遮阴程度加剧而增加。在构件水平上,除了茎部的全N质量分数外,遮阴处理下各构件的全C、N、P、K元素质量分数,以及茎和果实的w(C)∶w(N)、根的w(N)∶w(P)上升,根和叶的w(C)∶w(N),茎、叶和果实的w(N)∶w(P)则降低;凤丹所有构件在L63处理下w(C)∶w(P)降低,L34处理的凤丹根、茎和果实的w(C)∶w(P)上升。基于可溶性糖质量分数间接估计凤丹的源强度和库强度,结果显示,经L63处理的源强度和库强度显著提高,经L34处理的源强度和库强度则降低,遮阴处理显著降低凤丹的源库比。综上所述,凤丹通过调节生物量分配、改变化学计量特征,并协调源-库关系实现对遮阴的响应,凤丹经L63处理后生长与繁殖表现最好,暗示适度遮阴可提高凤丹产量。

With four-year-old Fengdan plantation in Tongling,Anhui Province,under different shading treatments(100%light,CK;63%light,L63;34%light,L34),the changes of biomass and stoichiometric characteristics of Fengdan were analyzed to explore the response of biomass and stoichiometric characteristics of Fengdan to the changes of light intensity.Compared with CK,in L63 treatment,the total biomass and stem biomass of Fengdan decreased,but the biomass of leaves and fruits increased by 10.75%and 335.69%,respectively;in L34 treatment,the total biomass and the biomass of each component decreased,but the biomass distribution of roots,leaves and fruits increased.Shading significantly increased the content of total C,total N and total K in Fengdan whole plant,the content of total P increased in L63 treatment and decreased in L34 treatment;Under L64 treatment,the content of w(C)∶w(N)and w(C)∶w(P)decreased significantly,the content of w(C)∶w(P)increased in L34 treatment,while the content of w(N)∶w(P)increased with the increase of shading degree.At the component level,in addition to the total N content of the stem,the total C,N,P,K element content of each component,as well as the w(C)∶w(N)and w(N)∶w(P)of the stem and fruit increased under the shading treatment,while the w(C)∶w(N),stem,leaf and fruit w(N)∶w(P)of the root and leaf decreased;the w(C)∶w(P)of all components of Fengdan decreased at L63,and the w(C)∶w(P)of the root,stem and fruit increased under the L34 treatment.From the content of soluble sugar,the source strength and sink strength of Fengdan were estimated indirectly.The results showed that the source strength and sink strength of L63 treatment increased significantly,while the source strength and sink strength of L34 treatment decreased,and the source sink ratio of Fengdan decreased significantly.These results showed that Fengdan could respond to shading by adjusting biomass distribution,changing stoichiometric characteristics,and coordinating source sink relationship.Fengdan had the best growth and reproduction performance in L63 treatment,suggesting that moderate shading could improve the yield of Fengdan.