树番茄幼苗生长与氮磷钾化学计量特征对光照、肥料的响应

Growth and N,P,K stoichiometric characteristics of Cyphomandra betacea seedlings in response to light and fertilizer

为研究树番茄幼苗的生长特性和N、P、K分配格局对光照和肥料的响应特征,揭示树番茄苗木生长规律、生理特性与光照和肥料的协调机制,以树番茄幼苗为研究对象,设置3个施肥量:无肥(F0)、中肥(F1,20 g·株^(-1))、高肥(F2,40 g·株^(-1)),设4个遮阴水平:无遮阴(L0,100%NR,NR为自然光照)、轻度遮阴(L1,75.0%NR)、中度遮阴(L2,52.8%NR)、重度遮阴(L3,30.0%NR),共12个处理组合。结果表明:树番茄幼苗通过增加对地上生物量的投资和减少对地下部分(根系)的投资来适应低光环境,52.8%NR条件下每株增施20 g复合肥,树番茄幼苗生长指标、生物量达到最大值;各器官的N、P、K含量及其化学计量比在不同处理组合中具有各自的变化规律,N、P、K含量均在叶中达到最大值,各器官N、P、K含量及其比值都存在显著相关关系;随着施肥和遮阴程度的改变,各器官养分分配存在权衡现象,全光照下,添加中肥有利于N、K向茎中分配,P向粗根中分配;遮阴后有利于N向叶分配,P和K向茎中分配;中度遮阴下每株增施20 g复合肥可以促进各器官N、P、K含量的分配;重度遮阴下每株增施40 g复合肥,养分含量明显降低。综上,树番茄的功能性状在不同光照和施肥处理下发生一系列适应性变化,光照、施肥均对树番茄幼苗的生长和氮磷钾化学计量特征产生显著(P<0.05)影响,中度遮阴和施肥处理能有效提高树番茄幼苗生长,以及养分的吸收和利用效率,促进各器官N、P、K含量的积累,促进幼苗的生长发育。

To investigate the growth characteristics and N,P,K allocation patterns of Cyphomandra betacea seedlings in response to light and fertilizer,and to reveal the coordination mechanism between the growth regulation,physiological characteristics,and light and fertilizer of C.betacea seedlings,experiments were carried out using 3 fertilizer levels:no fertilizer(F0),moderate fertilizer(F1,20 g per plant)and high fertilizer(F2,40 g per plant),and 4 shading levels:no shading[L0,100%natural light(NR)],light shading(L1,75.0%NR),moderate shading(L2,52.8%NR),and heavy shading(L3,30.0%NR),with a total of 12 treatment combinations.Results showed that C.betacea seedlings adapted to low light environment by increasing investment in aboveground biomass and reducing investment in underground parts(roots).At 52.8%NR,adding 20 g compound fertilizer per plant resulted in the maximum growth index and biomass of C.betacea seedlings.N,P,K contents and their chemical stoichiometry ratios in different organs had their own changing patterns in different treatment combinations,with N,P,and K contents reaching the maximum in the leaves.There were significant correlations between N,P,K contents and their ratios in various organs.With changes in fertilizer and shading levels,there were balancing phenomena in nutrient allocation to various organs.Under full sunlight,moderate fertilizer benefited the allocation of N and K to the stem and P to the coarse root.After shading,N was distributed to the leaves,while P and K were allocated to the stem.Moderate shading and the addition of 20 g compound fertilizer per plant could promote the distribution of N,P,and K contents in various organs.Under heavy shading and after adding 40 g compound fertilizer per plant,nutrient contents significantly decreased.Overall,the functional traits of C.betacea showed a series of adaptive changes under different light and fertilizer treatments.Light and fertilizer had a significant(P<0.05)impact on the growth and chemical stoichiometry features of C.betacea seedlings.Moderate shading and fertilization treatments could effectively improve the growth,nutrient uptake and utilization efficiency,and the accumulation of N,P,and K contents in various organs of C.betacea seedlings,promoting their growth and development.