植物根构型特性与磷吸收效率

植物根构型，即根系在生长介质中的空间造型和分布，与磷吸收效率密切相关；认识植物根构型，可为植物磷效率的遗传改良提供依据。长期以来，人们试图定量描述植物根构型，确立一个能客观全面地描述根系三维立体构型的综合指标。试验指出，植物主要通过向地性变化和根冠之间的碳源分配来改变根构型, 从而影响磷吸收效率；根系向地性变化可由缺磷等因素所诱导，且存在着一定的遗传变异性。有证据表明，根构型对低磷胁迫的适应性变化是受基因调控的一个生理过程，其中乙烯可能是一种重要的生理调节物质。迄今已在一些植物上定位到了部分控制根构型的数量性状座位，为该性状的分子生物学改良提供了基础。随着现代技术的进展，植物根构型研究将取得更大的突破。

Root Architectural Characteristics and Phosphorus Acquisition Efficiency in Plants

Root architecture, or the spatial configuration and distribution of root systems in the growth medium, is closely related to P cquisition efficiency. Understanding of root architecture may provide scientific basis of genetic improvement of P efficiency in plants. For a long time, attempts have been made to quantify root architecture and to establish a comprehensive criterion which can quantitatively describe the three_dimentional root architecture. Results from experiments indicate that changes in root architecture are mainly accomplished through root gravitropic sensitivity and carbon allocation between shoot and root, hence affecting phosphorus acquisition efficiency. Root gravitropic responses are adaptive, inheritable traits induced by low phosphorus availability and other factors. Evidence exists for a genetic regulation of gravitropic responses to low phosphorus availability, with possible involvement of ethylene as a hysiological regulator. To date quantitative trait loci (QTLs) conferring root architectural characteristics have been identified in some plants, offering hopes for molecular improvement of this trait. As modern technologies advance, great breakthrough is expected for root architectural research in the future.