Developmental and Functional Morphology of Crop Root System in Relation to Hydraulic Characteristic

作物根系发育及功能形态与水力特性的关系

基本信息

批准号：
13460008
负责人：
YAMAUCHI Akira
金额：
$ 7.49万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

This study aimed to examine several developmental and histological root traits that are closely related with water uptake and conductance of a seminal root system of sorghum seedling. In addition, the site of water entry and water uptake rate were determined by using sulphorhodamine G(SR) as an apoplastic tracer. It was then attempted to establish a hydraulic architecture of the root system based on these information.Results showed that heterorhizy exists in lateral roots traits examined such as branching, elongation and expansion ability, Casparian band, exodermis and endodermis development, xylem dimension and vascular connection to seminal root axis. The lateral roots accounted for approximately two third of both root surface area and total amount of SR accumulated in the root system. The accumulation of SR per unit root surface was different between root types and different portions along the seminal root axis. SR accumulated most on 0-15 cm portion from the tip. Among lateral roots, those emerged 15 cm away from the tip of seminal root axes accumulated SR most densely. These results indicate that this part is most active in water uptake in the root system. However, late metaxylem vessel (LMX) in the seminal root axis was not yet opened at that portion, indicating high axial hydraulic resistance. Furthermore, the accumulation drastically dropped basipetally from that portion on, whereas no clear difference in Casparian strip development and exo/endodermis maturity was detected between 15 cm and 20 cm portion from the tip.These facts suggest that the histological features that were determined in this study may not be the sole major factor to determine the hydraulic conductivity but some other traits like the permeability of cell membrane that is closely related with age and thus portion in a root system may also play important roles.

这项研究旨在检查几种与水吸收和高粱幼苗的开创性根系密切相关的发育和组织学性状。另外，通过使用硫丹明G（SR）作为占主塑性示踪剂，确定了水进入和水吸收速率的位置。然后，它试图基于这些信息建立根系的液压结构。结果表明，在研究，伸长和扩张能力的横向根部特征中存在异性腐蚀性到开创性根轴。横向根约占根系中累积的根表面积和总SR的三分之一。单位根部表面SR的积累在沿着精确根轴的根类型和不同部分之间有所不同。 SR在距尖端的0-15厘米部分积聚。在侧根中，距离精液轴尖端15厘米的人出现了最密集的SR。这些结果表明，该部分在根系中的水吸收中最活跃。然而，在该部分尚未打开，在该部分尚未打开元素轴中的晚期甲X系（LMX），表明高轴向液压电阻。此外，该部分的积累大幅下降，而在15 cm至20 cm的部分之间，从尖端中检测到Casparian Strip发育和Exo/exo/endodermis成熟度的明显差异。研究可能不是确定水力传导率的唯一主要因素，而是与年龄密切相关的细胞膜渗透性，因此根系中的一部分也可能起重要作用。