水分胁迫对辣木生物量分配和水分利用效率的影响

本研究以云南干热河谷辣木(Moringa olerfera)为对象,采用盆栽人工控制土壤含水量的方法,研究了水分胁迫对辣木生长、生物量分配和水分利用效率的影响。结果表明:90%和75%田间持水量控制下,辣木株高和地径随时间的延长逐渐增长,但70%田间持水量明显受到抑制;60%、45%和30%田间持水量处理下的株高和地径生长处于停滞状态;辣木复叶数、主根长和主根粗随水分胁迫加剧而降低,而根数无显著差异。利用标准化主轴法对株高-地径异速生长关系进行模拟,结果显示,随着干旱胁迫加剧,异速生长指数从1.273持续下降至0.947,即辣木将更多的同化物从株高生长转移到其他器官;不同土壤水分的生物量整体表现为根>茎>叶,且随着田间持水量的降低,辣木将更多的生物量由地上转移至地下,而水分利用效率整体呈上升趋势。

Effect of Soil Water Stress on Biomass Allocation and Water Use Efficient in Moringa oleifera Lam

A pot experiment was conducted to investigate the effect of soil water stress on growth, biomass allocation and water use efficient (WUE) of Moringa oleifera Lam (syn. M. ptreygosperma Gaertn). In this study, the height and basal diameter increased gradually with 90% and 75% field capacity (FC). Compared with 90% FC treatment, the growth of height and basal with 75% FC treatment were obviously restrained. The height and basal diameter growth under 60%, 45% and 30% FC treatment were generally stagnated. The compound leaf number, main root length and main root thick decreased with the decline of soil water content, while the root number showed no significant changing. Standardized major axis estimation (SMA) of height and basal diameter in M. oleifera showed that allometric exponent decreased continuous from 1.273 to 0.947 with the aggravation of drought stress, implying that more assimilation products were transported from  height growth to other organ construction. The biomass was generally ranked as root>stem>leaf, and much more biomass were shift from aboveground to underground to deal with the decrease of soil water potentials. The WUE of M. oleiferaincreased with the aggravation of water stress.