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Mechanisms of fruit cell expansion with intact water potential measurements

完整水势测量的果实细胞扩张机制

基本信息

批准号：
17580222
负责人：
NONAMI Hiroshi
金额：
$ 2.53万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17580222/
关键词：
Water potential measurements Psychrometer Cell expansion Water status measurements Cell turgor Fruit growth

项目摘要

Water potential measurements are usually conducted with the psychrometry by using excised tissues. When tissues are growing, and then, if excision is made in the zone of elongation for sampling, it is known that wall relaxation will take place. If wall relaxation due to excision takes place in the zone of elongation, water potential measurements with the psychrometer may not be accurately conducted because wall relaxation will make the measured value of water potential shift lower. However, the psychrometry is only a method which allows to measure the water potential in intact plants. Thus, improvement of the psychrometry is helpful for measuring water potential in intact plants. In order to improve the psychrometry, the output of a psychrometer was attempted to multiply by 3 times by malting a thermopile for the sensor of the psychrometer. The thermopile was made by combining 3 thermocouple junctions. Output of one thermocouple yields 480 nV per 0.1 MPa. Although the thermopile made in the present study should yield 3 times of 480 nV per 0.1 MPa, the output of the thermopile yielded only 2.0 to 2.4 times of that of one thermocouple. This failure might be due to connection between the thermocouples by using solder. The process of soldering between the thermocouples may yield the extra noise to reduce the thermocouple output. The water status of intact tomato fruit and endosperm cells of rice plants was measured with the pressure probe and psychrometers. Cell expansion in both plants was associated with the gradient of the growth-induced water potential High night temperature reduced the water potential gradient in endosperm cells of rice, resulting in yield decrease of rice at high temperature.

水势测量通常是通过使用切除的组织进行湿度计进行的。当组织生长时，如果在伸长区切除取样，就会发生壁松弛。如果在伸长区发生由于切除引起的壁面松弛，则用干湿计测量水势可能不准确，因为壁面松弛会使水势的测量值偏低。然而，湿度测量只是一种允许测量完整植物水势的方法。因此，湿度计的改进有助于测量完整植物的水势。为了改善湿度计的性能，我们尝试用麦芽制成的热电堆作为湿度计的传感器，使湿度计的输出倍增3倍。热电堆是由3个热电偶连接而成的。一个热电偶的输出电压为480 nV/0.1兆帕。尽管本研究制作的热电偶每0.1兆帕的输出电压为480 nV的3倍，但其输出功率仅为一个热电偶的2.0~2.4倍。这一故障可能是由于热电偶之间使用焊料连接造成的。热电偶之间的焊接过程可能会产生额外的噪音，从而减少热电偶的输出。用压力探头和干燥仪对完整的番茄果实和水稻胚乳细胞的水分状况进行了测定。夜间高温降低了水稻胚乳细胞的水势梯度，从而导致水稻在高温条件下减产。