云南松苗木生物量分配对平茬苗龄的响应

Response of biomass allocation of Pinus yunnanensis seedlings to the age of stumping seedlings

为揭示云南松苗木生物量分配对平茬苗龄的响应。分别以苗龄为6个月(处理1)、10个月(处理2)、14个月(处理3)、18个月(处理4)、30个月(处理5)的云南松苗木为试验材料进行统一平茬,分别于平茬后60、120、180、240、300、360、420、480 d使用全株收获法收获后测定单株、主根、侧根、茎、萌条、地下部分和地上部分生物量,并计算各构件的生物量分配比例,比较分析不同处理各构件生物量分配的差异。平茬后随时间变化,不同处理间各构件的生物量分配差异在缩小。苗龄较小的处理(1、2、3)均表现为:开始时萌条生物量分配比例最大且随苗龄的增加萌条生物量分配比例减少,表现为:萌条>茎>主根>侧根;地上部分>地下部分。从平茬后240 d开始,处理1与处理2、3、4间差异不显著。平茬也改变了苗龄较大的处理(4、5)各构件的生物量分配模式,60 d表现为:主根>茎>侧根>萌条,120~300 d表现为:茎>主根>萌条>侧根,而从360 d开始,处理4和处理5的各构件生物量分配模式逐渐转变为与处理1、2、3相一致,即表现为:萌条>茎>主根>侧根。综上所述,平茬可以通过利用植物补偿生长的特性来改变云南松苗木的生物量分配模式;平茬改变了不同平茬苗龄云南松的生物量积累和分配模式促进了苗木的萌蘖;不同平茬苗龄苗木随时间推移,云南松的生物量分配模式表现为生物量分配模式均表现为萌条生物量分配最大。本试验表明,苗龄较小的处理(1、2)进行平茬效果较好,是较适宜的平茬苗龄。

In order to reveal the response of biomass allocation of Pinus yunnanensis Framch.seedlings in different growth stages to the stumping age,uniform stumping was applied on P.yunnanensis seedlings at the age of 6 months(Treatment 1),10 months(Treatment 2),14 months(Treatment 3),18 months(Treatment 4),and 30 months(Treatment 5).Subsequently,the biomass were examined by whole plant harvest method on single plant,taproot,lateral root,stem,sprout strip,underground part and above ground part at 60,120,180,240,300,360,420 and 480 days after stumping.The proportions of biomass allocation for each component were calculated to analyze the differences in biomass allocation among the different treatments.As time progressed after stumping,the differences in biomass allocation among the different treatments began to narrow.For the younger age treatments(1,2,3),sprout biomass allocation was the highest initially and decreased with the increase of seedling age.The sequence of biomass allocation was as follows:sprout>stem>taproot>lateral root;above-ground portion>below-ground portion.240 days after stumping,the differences between Treatment 1 and other Treatments became insignificant.Stumping also altered the biomass allocation patterns for the older age Treatments(4,5)at 60 days,which were observed as follows:primary root>stem>lateral root>shoot.From 120 days to 300 days,the pattern shifts to stem>primary root>shoot>lateral root.After 360 days,the biomass allocation pattern for components in treatment 4 and 5 gradually transitioned to align with the other treatments,which was characterized by sprout>stem>taproot>lateral root.In summary,stumping can change the biomass allocation patterns of P.yunnanensis seedlings by utilizing the compensatory growth characteristics of plants.Stumping altered the biomass accumulation and allocation patterns of seedlings at different ages,and promoted sprouting.With the passage of time,the biomass allocation pattern of seedlings with different stumping age showed that the sprout biomass allocation was the largest.This experiment suggested that stumping is more effective for younger seedlings and is more suitable for such age groups.