高溫對水稻產量及品質之影響：從生理層次到田間環境之探討

Impacts of High Temperature on Rice Yield and Quality: From Physiological Level to Field Environment

莊豐鳴(Feng-Ming Chuang) ； 盧虎生(Huu-Sheng Lur)

《作物、環境與生物資訊》 10卷1期 (2013/03) Pp. 75-83

https://doi.org/10.30061/CEB.201303_10(1).0006

摘要

1980年代以來，全球地表均溫顯著上升，暖化問題日益受到重視。座落於亞熱帶的臺灣雖屬於海島型氣候，在水稻的栽培環境上卻面臨了高溫、高濕以及低光照等環境壓力之挑戰，彰顯了暖化及其衍生氣候快速變遷現象對農業的影響。氣候因子在水稻生長發育上扮演重要的角色，其中又以溫度為影響水稻產量與品質之關鍵因子。前人研究指出：高溫環境會造成稔實率及外觀品質下降，且水稻開花過程對於高溫最為敏感，一旦遭遇高溫，水稻花藥開裂比例下降，造成花粉散佈不良，進而誘導穀粒不稔實之發生；而在水稻充實階段遭遇高溫，會影響穎果內之能量狀態，促進穎果內之低氧及過氧化生理反應，並干擾合成澱粉及蛋白質之相關代謝產物及基因之表現，導致直鏈澱粉濃度下降、支鏈澱粉側枝延長、以及儲存性蛋白prolamins和globulins的含量下降，因而改變榖粒之理化性質及外觀品質。然而，異常高溫的出現有時候卻沒有對大田區之水稻稔實率造成預期的傷害，暗示僅藉由大氣溫度去評估高溫對水稻生育之衝擊未盡周延，需要進一步探討田間尤其是葉冠環境之熱量平衡狀態。例如，葉冠內之穗溫可受到濕度及風速等環境因子的影響而變異，進而干擾其穎果發育。此外，穗溫與稔實率間具有顯著相關性，故穗溫似可作為關聯田間熱量平衡及最後稻穀產量與品質之指標。目前文獻對於提高水稻在田間高溫環境的適應力方面，可歸納出兩個方向：（1）育種上，可發展提早開花及花藥開裂長度較長的品種，以提高對高溫的耐受性，並研發適合臺灣環境之耐熱篩選指標及育種理想型；（2）栽培上，適時適量調整穗肥施用，並搭配葉色監測及肥培管理，可減緩高溫對品質及產量造成的傷害，另可調整插秧期或栽培密度，避免在開花抽穗期遭遇高溫。

關鍵字

水稻 ； 高溫 ； 不稔實率 ； 品質 ； 穗溫

並列摘要

Global average surface temperature has risen substantially since 1980 and hence, the issues of warming impact have received much attention in recent years. Although located in the subtropical zone, Taiwan is facing the threat of environmental pressures, such as high temperature (HT), high humidity and low solar radiation. Environmental factors play an important role in rice growth and development; in particular, temperature is considered the most critical one to affect rice yield and quality. Previous studies indicated that HT can reduce rice fertility and appearance quality. Flowering is the most sensitive process to HT, and HT may impair anther dehiscence and interrupt pollen shedding resulting in sterility. During grain filling stage, the energy status of caryopsis can be altered by HT, and physiological processes related to hypoxia and oxidative stresses are enhanced. As a result, the biosynthesis of macromolecules including starch and protein is interfered. HT may also reduce amylose content and enrich long side-chain amylopectin, causing the decrease of prolamins and globulins. However, high temperature may not always induce sterility in the paddy field, implying that factors other than air temperature may also be involved. Some studies show that the thermal balance of canopy is more directly link to the high temperature induced sterility. Changes in panicle temperature seem even more closely related to grain fertility and may be a good physiological index for assessing field thermal balance. Summarized from the literature, two aspects are suggested for ameliorating high temperature stress: (1) for breeding, such as develop early-morning flowering cultivars, select varieties with long anther dehiscence trait, establish heat-tolerance selecting indices and breed ideotype according to cultivation environment in Taiwan; (2) for cultivation, such as apply panicle fertilizer properly with SPAD meter monitoring and adjust transplanting date or planting density to avoid encountering HT at heading stage.

並列關鍵字

Rice ； High temperature ； Sterility ； Quality ； Panicle temperature