喀斯特特有植物罗甸小米核桃响应土壤水分的表型可塑性

为了解喀斯特特有植物在不同水分条件下的可塑性差异及适应能力,以1年生罗甸小米核桃幼苗为研究对象,设置不同水分条件[(100±5)％、(80 ±5)％、(60 ±5)％、(40 ±5)％],探讨罗甸小米核桃幼苗形态、生物量分配和生理特征的可塑性差异.结果表明,与CK组相比,罗甸小米核桃幼苗在高水与低水胁迫下的苗高、地径生...

Plasticity of a karst endemic plant Juglans regia L. f. luodianense Liu et Xu in response to soil moisture

To understand the adaptability and the plasticity difference of Karst endemic plants to different water conditions, taking 1-year-old Juglans regia L. f. luodianense Liu et Xu as the study material, the differences in plasticity of morphological, biomass allocation, physiological characteristics of seedlings of J. regia L. f. luodianense Liu et Xu were discussed under different water conditions [(100±5)%, (80±5)%, (60±5)%, (40±5)%]. The results showed that, compared with CK group, the response of J. regia L. f. luodianense Liu et Xu under high and low water stress was as follows: seedling height, ground diameter growth, root length, leaf area and specific leaf area all decreased; fleshy degree of leaves significantly decreased, and compactness of leaf tissue structure increased under moderate low water stress (40±5)%. Distribution of plant stem and leaf resources decreased, the root resource input and the root-cap ratio increased under moderate low water stress, and total biomass decreased. Net photosynthetic rate (P_n) and transpiration rate (T_r) were all reduced, stomatal conductance (G_s) was slightly increased at mild high water level (100±5)%, and intercellular CO₂ concentration (C_i) was basically stable. The content of chlorophyll b and total amount of chlorophyll only increased under mild high water stress. Based on the plasticity indexes (ranging from 0.02 to 0.50) of seedlings of J. regia L. f.luodianense Liu et Xu under different water conditions, the net photosynthetic rate was up to 0.50, followed by leaf area and stem biomass, and chlorophyll a had a minimum plasticity of 0.02. There were significant differences in the sensitivity and regulatory mechanism to the plastic responses of different water conditions of seedlings of J. regia L. f. luodianense Liu et Xu, which were regulated by leaf area, stem biomass, and net photosynthetic rate. Under normal water supply (80±5)% and mild high water stress (100±5)%, the water demand for the growth of seedlings of J. regia L. f.luodianense Liu et Xu could be satisfied.