三种草本豆科植物通过协同的茎和根的适应生长反应，在最适温度和有限磷供应条件下增强生长。
Adaptive shoot and root responses collectively enhance growth at optimum temperature and limited phosphorus supply of three herbaceous legume species.
机构信息
School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley WA, Australia.
出版信息
Ann Bot. 2012 Oct;110(5):959-68. doi: 10.1093/aob/mcs166. Epub 2012 Jul 29.
BACKGROUND AND AIMS
Studies on the effects of sub- and/or supraoptimal temperatures on growth and phosphorus (P) nutrition of perennial herbaceous species at growth-limiting P availability are few, and the impacts of temperature on rhizosphere carboxylate dynamics are not known for any species.
METHODS
The effect of three day/night temperature regimes (low, 20/13 °C; medium, 27/20 °C; and high, 32/25 °C) on growth and P nutrition of Cullen cinereum, Kennedia nigricans and Lotus australis was determined.
KEY RESULTS
The highest temperature was optimal for growth of C. cinereum, while the lowest temperature was optimal for K. nigricans and L. australis. At optimum temperatures, the relative growth rate (RGR), root length, root length per leaf area, total P content, P productivity and water-use efficiency were higher for all species, and rhizosphere carboxylate content was higher for K. nigricans and L. australis. Cullen cinereum, with a slower RGR, had long (higher root length per leaf area) and thin roots to enhance P uptake by exploring a greater volume of soil at its optimum temperature, while K. nigricans and L. australis, with faster RGRs, had only long roots (higher root length per leaf area) as a morphological adaptation, but had a higher content of carboxylates in their rhizospheres at the optimum temperature. Irrespective of the species, the amount of P taken up by a plant was mainly determined by root length, rather than by P uptake rate per unit root surface area. Phosphorus productivity was correlated with RGR and plant biomass.
CONCLUSIONS
All three species exhibited adaptive shoot and root traits to enhance growth at their optimum temperatures at growth-limiting P supply. The species with a slower RGR (i.e. C. cinereum) showed only morphological root adaptations, while K. nigricans and L. australis, with faster RGRs, had both morphological and physiological (i.e. root carboxylate dynamics) root adaptations.
背景与目的
在磷（P）供应受限的情况下，关于亚适宜和/或超适宜温度对多年生草本物种生长和磷营养的影响的研究较少，并且对于任何物种，温度对根际羧酸动力学的影响也不清楚。
方法
测定了三种昼夜温度制度（低，20/13°C；中，27/20°C；高，32/25°C）对 Cullen cinereum、Kennedia nigricans 和 Lotus australis 生长和磷营养的影响。
主要结果
最高温度有利于 C. cinereum 的生长，而最低温度有利于 K. nigricans 和 L. australis 的生长。在最佳温度下，所有物种的相对生长率（RGR）、根长、根长与叶面积比、总磷含量、磷生产力和水分利用效率都较高，并且 K. nigricans 和 L. australis 的根际羧酸含量较高。具有较慢 RGR 的 C. cinereum 具有较长（较高的根长与叶面积比）和较细的根，以通过在最佳温度下探索更大的土壤体积来增强磷的吸收，而具有较快 RGR 的 K. nigricans 和 L. australis 只有较长的根（较高的根长与叶面积比）作为形态适应，但在最佳温度下其根际羧酸含量较高。无论物种如何，植物吸收的磷量主要取决于根长，而不是单位根表面积的磷吸收速率。磷生产力与 RGR 和植物生物量相关。
结论
所有三种物种在磷供应受限的情况下，在最佳温度下均表现出适应于增强生长的地上部和根系特征。具有较慢 RGR 的物种（即 C. cinereum）仅表现出形态学根适应，而具有较快 RGR 的 K. nigricans 和 L. australis 则既有形态学和生理学（即根羧酸动力学）根适应。
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