乙烯和多元胺對高溫下水稻穀粒發育的關係

Correlation among Ethylene, Polyamines, and Development of Rice Grains Growing under High Temperature

陳瀅如(Ying-Ju Chen)

指導教授 ： 盧虎生

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.00361

摘要

為了瞭解在高溫下乙烯、多元胺對於穀粒發育的影響，本試驗採用栽培種台稉九號作為試驗材料，並區隔為上下穗位探討。對水稻抽穗前6天到開花後8天的各發育時期作4小時35/30℃(日/夜)高溫處理發現，在高溫處理下的開花期水稻乙烯釋放量均明顯提升，但在抽穗前3天的時期高溫處理結果，乙烯釋放量下降。另外也收取水稻在35/30℃高溫處理下生長的穗計算充實率，結果發現在高溫下水稻上下穗位的平均充實率均比上穗位下降。

在穀粒充實期方面，35/30℃高溫處理從水稻開花後第六天開始，水稻在高溫處理下，開花後第九天出現一個乙烯釋放量的高峰，而在第15天出現第二個高峰期，且全充實期乙烯釋放量均高於控制組。在25/20℃控制組下，在開花後15天和開花後18天出現乙烯釋放量的高峰，在穀粒的粒重方面，35/30℃高溫生長下的穀粒粒重較控制組輕。為了進一步了解乙烯的釋放量提早且提升是否對於穀粒的重量及品質造成影響，我們使用乙烯抑制劑及乙烯釋放劑對穀粒充實期中最敏感的時期開花後12天~開花後16天作處理。結果發現在25/20℃控制組中使用乙烯釋放劑ethephon會造成穀粒粒重下降，白堊質比例提升，而在35/30℃高溫對照組中使用乙烯抑制劑Ag(NO)3則會使穀粒白堊質的面積下降。

在35/30℃高溫下充實的穀粒，總多元胺的含量較25/20℃控制組低。35/30℃高溫下，Putrescine含量則是在開花後第12天達到高峰，之後急速下降，25/20℃控制組則是在開花後15天到達高峰，之後緩慢下降。Spermidine在35/30℃高溫下全充實期在穀粒內含量均低於25/20℃控制組。Spermine在35/30℃高溫下全充實期在穀粒內的含量均高於25/20℃控制組。這樣的情況在上下穗位中均有一致的結果。
綜合本研究結果發現，在高溫下水稻穀粒乙烯釋放量會增加且提早，而相對於乙烯，多元胺的含量則是下降，顯示高溫下乙烯與多元胺的濃度失衡，而造成穀粒充實不良而粒重下降且產生白堊質。因此，乙烯和多元胺在穀粒發育過程中的平衡對於能否正常發育有著相當的重要性。

關鍵字

台稉9號 ； 高溫 ； 乙烯 ； 充實率 ； 穀粒品質 ； 多元胺

並列摘要

Global warming is an important problem in this world. In Taiwan, the average temperature increased 1.1℃ in the past century. Rice is known to be sensitive to high temperature, especially during grain filling stage. Some research revealed that rice had lower filling spikelet rate and chalky appearance under high temperature. Plant hormones involve in regulation of grain development. Reports showed that high ethylene evolution leaded to grain abortion or abnormal grain. And polyamines, as precursor competitors of ethylene, also play an important role on the grain filling stage. Nevertheless, few documents have been dealing with the role of ethylene and polyamines during grain filling stage under high temperature. The objective of this study was to explore the correlation among ethylene, polyamines, and grain filling under high temperature.
Cultivar TK9 was used as plant material. Panicles were samples and separated into two groups, superior spikelets and inferior spikelets. Superior spikelets in general have higher grain yield and better quality than inferior spikelets. Physiological characteristics were determined and compared between superior and inferior spikelets under high temperature. First, the ethylene evolution rate was measured on booting stage to flowering stage under high temperature. Then we chose the panicles that was on the stage of 6 days before heading to 8 days after flowering, and transferred the plant material to 35/30℃ (day/night) for 4 hours. Plant materials were also chosen on the day of heading and transferred to 35/30℃ (day/night) until mature in order to count the filling spikelet rate. At the grain filling stage, panicles were chosen at the 6 day after flowering, and transferred to 35/30℃ (day/night) until mature.
The results showed that spikelets fertility decreased under high temperature. During the stage of 6 days before heading to 8 days after flowering, ethylene evolution rate increased under high temperature. Superior spikelets and inferior spikelets behaved similarly. There was significant negative correlation between ethylene evolution rate and spikelets fertility under high temperature.
At the grain filling stage, the results indicated that grain filling rate increased but stopped earlier under high temperature. Grain weight and grain quality also decreased under high temperature. In both superior spikelets and inferior spikelets ethylene evolution rate increased under high temperature. The result also showed significant negative correlation between ethylene evolution and grain yield. In order to clarify relationship between ethylene and grain yield, Ag(NO)3 (ethylene inhibit agent) was applied under high temperature and ethephon (ethylene release agent) was applied under control temperature for 5 days on the panicle at the 12 days after flowering. Application of Ag(NO)3 improved grains quality and increased weight, but application of ethephon decreased grains quality and weight. The results indicated that ethylene may have strong effect on the grain yield and quality under high temperature. Content of total polyamines were decreased under high temperature. Content of spermine increased under high temperature, while putrescine and spermidine decreased. The decrease in total polyamines content may induce negative effect on the grain yield and quality under high temperature.
In conclusion, this study found that an increased ethylene evolution rate might be related to the spikelets sterility under high temperature at the booting to flowering stage. At the grain filling stage, ethylene evolution rate increased and total polyamines decreased and may negatively affect the grain yield and quality under high temperature. In conclusion, the change of ethylene had temporal correlation with that of polyamines, suggestion a correlative relationship in the regulation of caryopsis development under high temperature.

並列關鍵字

TK9 ； high temperature ； ethylene ； grain filling rate ； grain quality ； polyamines

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