The effects of nitrogen dosages to the carbon and nitrogen metabolism of soybean(Kaohsiung Sel.10) and vegetable soybean( Kaohsiung 3)

• Main Authors: Lin, Shu-Mei, 林淑美
• Other Authors: Ching-Yih Chen, Song-Iuan Liaw
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/29775092231464835128

碩士 === 國立中興大學 === 植物學系 === 85 === Our research focused on soybean cultivar Kaohsuing Sel. 10(Glycine max (L.) Merr. cv. Kaohsuing Sel. 10) and vegetable soybean cultivar Kaohsuing 3 (Glycine max (L.) Merr. cv. Kaohsuing 3). We treated the samples with different amounts of nitrogen fertilization using urea as a nitrogen source, and analyzed its effects on the carbon and nitrogen metabolism of the leaves during the flowering stage and seed filling period. The experimental results showed that there were different levels of influence of nitrogen treatment to different cultivars and their growth stages.The effectsof the addition of nitrogen treatment affected leaf CO2 assimilatory rates more on the soybean than the vegetable soybean. The addition of nitrogen led to a decrease of respiratory rate of both soybean and vegetable soybean leaves,which resulted in discrepancy of carbon skeleton and thus the consequential biochemical reactions. In addition,the yield was affected by assimilate translocation and distribution. Twofold and threefold nitrogen treatments raised the ratio of assimilates partitioning to the soybean pod while there were no obvious effects of which to the assimilates partitioning in vegetable soybean.But, there were noobvious effects on the harvest index,perhaps being attributed to of both soybeanand vegetable soybean under different amounts of nitrogen fertilization.It mightbe the failure of efficient translocation of assimilates to pods. During the flowering and seed filling stages, the glutamate dehydrogenase activity of soybean and vegetable soybean leaves was higher than the glutamine synthetase activity. The addition of nitrogen fertilization increased the glutamine synthetase activity and yet it was unable to increase the glutamate dehydrogenase,therefore under the high nitrogen situation, soybean and vegetablesoybean used glutamine synthetase pathway to metabolise ammonium in leaves.Otherthan this, during the flowering and seed filling stages, the glutamate contents were higher than glutamine inside the soybean and vegetable soybean leaves.Whichindicated that glutamate dehydrogenase took part in metabolising the ammonium. During the flowering and seed filling stages, asparagine, the highest quantityamino acid could be used to synthesize other amino acids through transamination without consuming too much energies. This was beneficial to the developing pods.Soybean seeds contain a large amount of protein (about 33.1% to 49.2%),therefore, during the seed filling stage, it was beneficial to protein synthesis as the asparagine contained in the soybean leaves to transport to the seeds. We found that addition of nitrogen fertilization raised the photosynthetic rate in both soybean and vegetable soybean and yet it had little effects in the nitrogen assimilation and thus was unable to translocate the ample nitrogen contained in the leaves to the pods. Therefore, there was no trivial correlationbetween the nitrogen assimilation and the yields. Further studies about the correlation of seed growth and the nitrogen content in the leaves must be done in order to understand that whether the assimilation and partioning efficiency of soybean and vegetable soybean is a restrictive factor to the seed growth.