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標題: 根溫處理對溫室洋香瓜氮代謝之影響
Effects of Root Temperature on the Nitrogen metabolism of muskmelon (Cucummis melo L.)
作者: 郭建榮
Guo, Jain-Rong
關鍵字: root temperature;根溫;nitrogen metabolism;muskmelon;氮代謝;洋香瓜
出版社: 植物學系
以水氣耕栽植之溫室洋香瓜( Cucummis melo L. )為材料,用循環水
及地上部之生長,生理機能及氮代謝 酵素活性關係.結果顯示溫室洋香瓜
吸收速率,葉片光合作用能力及碳同化作用( Rubisco活性 )皆下降,因此,
碳骨架與能量來源受到限制而造成植物生長受抑制. 植物的固氮作用
之呼吸作用會下降,能量來源不足,致使固氮作用的酵素活性( 包括NR,
NiR, GS, GOGAT )偏低.植株為維持正常生理代謝上氮源的需求,低溫處理
要則由根部組織進行.因此,固氮酵素活性較低溫處理株高. 結果期,植
amide 中的Asparagine(Asn)為主要氮源輸送的有機形式.Glu和Gln為
用GS/GOGAT cycle的進行,轉換成Glu和Gln的 形式,提供給Asn

The aim of this study was to elucidate the effects of the
different root temperatures (35, 25, 15 degree )on growth and
nitrogen metabolism of muskmelon (Cucummis melo L.) under the
hydroponic system. Examinations on the changes of the
physiological characterics under different root temperatures
including biomass, photosynthetic rate, respiration rate,
stomatal conductance, content of free amino acid, soluble, and
the enzyme activities of NR, NiR, GS, GOGAT,GDH, and Rubisco.
The results were summarized as follows: The decreasing of
root temperature resulted in the decreasing of photo-synthetic
rate, respiration rate, Rubisco activity and total dry weight in
leaves. The lowest root temperature inhibited the absorpting of
nutrition onplant growth. Undeer 15 degree root temperature
treatment, the content of total solubleprotein was lowest in
both roots and leaves. Furthermore, the activities ofNR and NiR
were lowest in root, but highest in leaves. The reason may be an
increasing in the flow rate of nitrate into leaves. Therefore,
the assimilation of nitrogen increasing in leaves on low
temperature. In higher plants, ammonina is mainly assimilated by
GS and GOGAT pathway which produces glutamine andglutamate. The
low temperature inhibited GS/GOGAT activities in roots.
Thereforethat is favorable to ammonium assimilation in leaves.
Our results showed that indeed asparagine was the highest
content among 20amino acids in leaves and roots of all root
temperature treatments. In fruit growth period, the transmitting
of asparagine is very important from leaves and roots. For this
reason, changes in amino acids content and composition of sink
(fruit) was more important than the effect of root temperature.
Appears in Collections:生命科學系所

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