光照和氮素对芒萁克隆繁殖特性及生物量分配的影响

  目的  研究不同光照和施氮水平对芒萁Dicranopteris dichotoma克隆繁殖特性和生物量分配的影响，旨在为芒萁单优层片发育过程提供理论依据。  方法  采用盆栽控制试验，设置3种光照透光率35.96%(L₁)、13.00%(L₂)和4.75%(L₃)]和2种氮素水平施氮(N₁)和不施氮(N₀)]，比较分析光照和氮素对芒萁克隆繁殖特性及生物量分配的影响。  结果  ①在2种氮素水平下，L₂处理的根状茎芽数出现最大值，L₃处理的克隆分株数显著低于L₁和L₂(P＜0.05)。施氮显著提高了各遮光下克隆分株数和芽数(P＜0.05)，分别增加了124.7%(L₁)、82.8%(L₂)、53.8%(L₃)和70.0%(L₁)、125.7%(L₂)、122.5%(L₃)。②在2种氮素水平下，克隆分株株高随遮光程度增加显著增加(P＜0.05)，L₃处理的羽叶长显著高于L₁和L₂(P＜0.05)，叶宽无显著差异(P＞0.05)。施氮水平下，L₁和L₃处理的克隆分株株高显著增加(P＜0.05)，L₁处理的羽叶长显著增加(P＜0.05)，L₃处理的羽叶长显著降低(P＜0.05)，L₂处理的株高和叶长增加均不显著(P＞0.05)。③在2种氮素水平下，L₃处理的克隆分株地上与地下生物量(干质量)比、生物量羽叶分配比例显著高于L₁和L₂处理(P＜0.05)，根状茎分配比例显著低于L₁和L₂(P＜0.05)，各遮光处理芒萁克隆分株生物量羽叶分配比例显著高于根状茎(P＜0.05)，根状茎显著高于茎和细根(P＜0.05)。  结论  L₂处理更有利于芒萁克隆分株的形成，施氮有利于芒萁克隆繁殖能力的增强；L₃处理的克隆分株可通过增加株高、叶长以及生物量叶分配比例适应弱光生境；无论何种光强资源及氮素水平，芒萁均优先保证羽叶的生长，其次保证根状茎生长。图2表5参38

Effects of light and nitrogen on clonal reproduction characteristics and biomass allocation of Dicranopteris dichotoma

Objective]To study the effect of different light and nitrogen application on the clonal propagation characteristics and biomass distribution of Dicranopteris dichotoma,aiming to provide a theoretical basis for the development of monolayers of D.dichotoma.Method]Three light intensitieslight transmittance 35.96%(L1),13.00%(L2)and 4.75%(L3)],and two nitrogen levelsnitrogen application(N1)and no nitrogen application(N0)]were set up in pot experiments.The effects of light intensity and nitrogen on clonal reproduction characteristics and biomass allocation were analyzed.Result](1)Under the two nitrogen levels,the number of rhizome buds in L2 treatment was the highest.The number of clonal ramets of L3 treatment was significantly lower than that of L1 and L2(P<0.05).Nitrogen application significantly increased the number of clonal ramets and buds of D.dichotoma under different shading conditions(P<0.05),with an increase rate of 124.7%(L1),82.8%(L2)and 53.8%(L3)and 70.0%(L1),125.7%(L2),122.5%(L3),respectively.(2)Under the two nitrogen levels,the height of clonal ramets increased significantly(P<0.05)with the increase of shading degree,and the length of leaves in L3 shading condition was significantly higher than that in L1 and L2(P<0.05),but there was no significant difference in leaf width(P>0.05).Under nitrogen application level,the clonal ramet height of L1 and L3 treatments increased significantly(P<0.05),the leaf length in the L1 treatment increased significantly(P<0.05),and the leaf length in L3 treatment decreased significantly(P<0.05).Both plant height and leaf length in L2 treatment did not increase significantly(P>0.05).(3)Under the two nitrogen levels,the aboveground and underground biomass(dry weight)ratio and biomass allocation ratio of clonal ramets in L3 treatment were significantly higher than those in L1 and L2 shading treatments(P<0.05).The rhizome distribution ratio was significantly lower than that of L1 and L2(P<0.05).The percentage of biomass and leaf allocation of each shading treatment was significantly higher than that of rhizomes(P<0.05),and rhizomes were significantly higher than stems and fine roots(P<0.05).Conclusion]L2 treatment is more conducive to the formation of clonal ramets,and nitrogen application is conducive to the enhancement of clonal reproduction capacity.Clonal ramets of L3 treatment can adapt to low-light habitat by increasing plant height,leaf length and biomass leaf allocation ratio.Regardless of the light intensity and nitrogen level,D.dichotoma gives priority to ensuring the growth of feather leaves,followed by rhizomes.