Phenotypic Plasticity of Mosla Chinensis and M. Scabra (Labiatae) Response to Soil Water Status

本文比較研究了華薺苧 (Mosla chinensis Maxim.) 和同屬植物石薺苧油(Mosla scabra (Thunb.) C. Y. Wu et H. W. Li) 的生長和形態特徵回應水分條件的表型可塑性。萌發兩周後的幼苗在5種水分條件下處理6周左右。處理條件是類比野外自然降水，分別為：持續飽和、100%-80%田間持水量(water holding capacity, WHC)、100%-60% WHC、100%-40% WHC 以及100%-20% WHC （分別類比不同的降雨間隔期）。結果表明：兩個物種的總生物量、根生物量、株高、基莖粗、累加分枝長和枝鮮/幹重比在回應不同的相對土壤含水量時都表現出市制表型可塑性，而且石薺寧的這些特徵的表型可塑性大部分大於華薺寧；但是兩個物種的葉生物量比(leaf mass ratio, LMR)、比葉面積(specific leaf area, SLA)、根生物量比(root mass ratio, RMR)和根冠比(root/shoot,R/s)則表現出低的可塑性。此外，葉生物量，枝生物量，枝生物量比(branch mass ratio, BRM)在華薺寧中表現出高可塑性，但在石薺寧中則表現出低可塑性，分枝數正相反。石薺寧更多地通過生物量和植株大水的可塑性來回應水分，而華薺寧則通過枝和根特徵的少量可塑性來回應水分。兩個物種的最適水分生態位為40%WHC到飽和水分。華薺寧在乾旱條件下生長緩慢，植株矮小，使它在野外群落中不具有競爭優勢；而石薺苧則以相對較高的生物量和高大的植株，在群落中具有競爭優勢。

關鍵字

種間差異；華薺苧；石薺苧；表型可塑性；土壤相對含水量；水分生態位

並列摘要

The growth and architectural plasticity of Mosla chinensis Maxim. in response to soil water status were compared with the congeneric plant, Mosla scabra (Thunb.) C. Y. Wu et H. W. Li. Two-week-old seedlings were exposed to five levels of soil water for a 6-week period. The results indicated that: an individual’s total mass, root mass, apical height, basal diameter, accumulative branch length and branch fresh weight/dry weight ratio (FW(subscript B) /DW(subscript B)) of both species had high plasticity in response to soil water content (p＜0.05), and the plasticity of these traits in M. scabra is mostly higher than in M. chinensis. The leaf mass ratio (LMR), specific leaf area (SLA), root mass ration (RMR), and root/shoot ratio (R/S) of both species had low plasticity. Furthermore, leaf mass, branch mass, branch mass ratio (BMR). and branch length ratio (BLR) had high plasticity (P＜0.05) in M. chinensis but not in M. scabra (P＞0.05) while branch number exhibited contrary trends. In response to soil water, M. scabra adjusted the traits of total mass and size, in terms of a bigger PI, more than M. chinensis while M. chinensis only adjusted partial branch and root traits, such as BMR, BLR, FW(subscript B)/DW(subscript B), RMR and R/S, more than M. scabra. The optimum water niches (OWN) of both M. chinensis and M. scabra are from 40% soil water holding capacity (WHC) to constant saturation, but M. chinensis is only found in relatively dry environments while M. scabra is distributed from dry to wet environments in the field, so the actual water niche (AWN) was separated from the OWN in M. chinensis, but not in M. scabra. Mosla chinensis grew slower and remained smaller than M. scabra and other neighbor species in the field, and it therefore had no competitive superiority in the community. Mosla scabra was very competitive because of its higher yield and taller growth.

並列關鍵字

Interspecific difference ； Mosla chinensis ； Mosla scabra ； Phenotypic plasticity ； Relative soil water content ； Water niche

國際替代計量

Phenotypic Plasticity of Mosla Chinensis and M. Scabra (Labiatae) Response to Soil Water Status

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