摘要
以中小径级的低产毛竹(Phyllostachys edulis)林为研究对象,通过土壤轮休覆盖模式试验,分析毛竹克隆分株的产生规律及其地下鞭系统、间隔子行为和细根生物量垂直分布,探讨毛竹克隆种群的行为学机制及其对竹林生态系统的影响。研究发现,毛竹克隆分株萌发率处于(20.65±4.03)%^(35.26±1.18)%之间,其利用富足的营养爆发式萌发克隆分株,第1年覆盖和第3年覆盖的克隆分株数量分别达(35.2±7.7)和(27.8±4.2)株·m^(-2),打破了在漫长进化过程中形成的自身固有生长发育与繁殖的生活史节律,是一种被动适应;覆盖可增加眉围,随着覆盖时间的增加,眉围均值下降;覆盖极大地增加了幼鞭休眠芽数量,随着覆盖时间的增加,幼鞭和壮老鞭休眠芽的数量均会下降,轮休后,休眠芽数量有所恢复;轮休期一定程度上减少了幼鞭长度的比例,但随着轮休时间的增加,幼鞭长度比例有所上升,毛竹利用减小幼鞭直径、增加幼鞭长度和间隔子长度这种资源吸收结构的可塑性来达到开拓适宜生境的目的;第3年覆盖的平均细根生物量为第1年覆盖的64.07%,覆盖使细根生物量减少,并使其生物量分布趋向于土壤上层,轮休可使细根向较深土壤层生长,并使细根生物量回升;对照毛竹林在土壤表层和深层分配大量细根生物量,这与覆盖轮休模式只有1个峰值不同,说明细根针对不同的生境采取不同的生物量分配方式进行觅食。因此,覆盖第3年已出现衰退现象,轮休是覆盖的必要补充。
A field experiment was carried out on adoption of a mulching and fallow alternation system in a tract of lowyielding moso bamboo groves,of small and medium in diameter,to explore effects of the practice on generation pattern of ramet,root system,spacing behavior and vertical distribution of fine roots of the plants and on behavioral mechanism of the clonal population and ecosystem of the bamboo groves.The experiment had five sample plots set for treatments,separately:control(CK),mulching in the first year(C1),mulching in the third year(C3),alternate in the first year(R1) and alternate in the second year(R2).Results show that ramet germination rate of the Moso Bamboo ranged between(20.65±4.03) %-(35.26±1.18) % relative to season.Rich soil nutrients in the soil triggered explosive ramet.In Treatment C1 and C3 the number of ramet reached(35.2±7.7) and(27.8±4.2) per square meter,respectively,breaking up the autologous rules of life developed through a long evolution process,concerning growth and multiplication,which is a type of passive adaptation.Mulching with organic materials initially elevated diameter of the bamboo at eyebrow height,but reduced it with the mulching going on.Moreover,it raised significantly the number of dormant buds on new roots(1-2 years old),but affected reversely the number of dormant buds on both new and prime roots with the mulching going on.The number of dormant buds began to turn up when fallow started.To a certain extent,fallow reduced elongation rate of the young roots,but later on it increased the rate somewhat.Moso Bamboos took advantage of the plasticity of its nutrient adsorption organ,i.e.root,in structure,such as reducing diameter of its new roots,and increasing length of its new rootsand extending space between buds on the new roots,to open up a new suitable habitat.In Treatment C3,the mean biomass of fine roots declined down to 64.07% of that in Treatment C1.Mulching not only reduced the biomass of fine roots,but also had it concentrated in the surface soil layer,while fallow promoted growth of fine roots deeper and increased the biomass of fine roots as well.In Treatment CK,large volumes of fine roots were distributed in both the surface and sub-soil layers,and Treatments R1 and R2 differed from Treatment CK only in peak value,which indicates that the fine roots of bamboo adapt to different habitats by redistributing the biomass.The technique of mulching the field with organic materials in bamboo forest is an efficient approach to increase and maintain soil temperature and moisture in order to enhance shoot bud formation and early germination.However,Treatment C3 did demonstrate that mulching obviously affects the number of dormant buds,the length of new roots,the space between buds and the biomass of fine roots,while the subsequent fallow helped restore them somewhat.It is,therefore,concluded that fallow is an essential complement to mulching for bamboo groves.
出处
《生态与农村环境学报》
CAS
CSCD
北大核心
2017年第3期234-241,共8页
Journal of Ecology and Rural Environment
基金
浙江省科技计划(2016F50008)
浙江省省院合作林业科技项目(2015SY06)
浙江省竹子高效加工重点实验室项目(2014F10047)
关键词
散生竹
克隆分株
休眠芽
间隔子
细根
monopodial bamboo
ramet
dormant bud
spacer
fine root