• 作者： 宋濟民; 楊純明; 陳宗禮
• 作者服務機構： 國立中興大學糧食作物研究所
• 中文摘要： 本試驗主要目的在探討葉片內外相對濕度階差及乾旱處理對於稻株葉片擴散阻力與蒸散量之影響。 試驗結果顯示：當葉片內外相對濕度階差增加時，葉片擴散阻力亦隨之升高。二者間之關係，在乾旱處理下尤其明顯。葉片內外相對濕度階差與葉片擴散阻力間之關係在乾旱處理下，品種間之差異也較明顯，此可能是導致供試兩品種在乾旱處理下蒸散量差異之主要原因。葉片蒸散量之增加直接誘導葉片水份潛勢降低，但在對照組中，葉片水分潛勢降低至-1.35 MPa即維持此一水平，不再因蒸散量之增加而改變。這可能與其植株水份傳導阻力之改變有關。但在乾旱處理下，稻株葉片水份潛勢則隨蒸散量之增加而繼續下降。
• 英文摘要： This paper describes the effect of water stress and humidity gradient between leaf and air on stoma-tal response, transpiration and plant resistance in two rice (Oryza sativa L.) genotypes. Leaf diffusive re-sistances were increased as humidity gradient increased. Changes occurred in plants exposed to water stressto make stomata more sensitive to humidity gradient. Under water stressed conditions, distinct genotypicdifferences in stomatal response to humidity gradient were also apparent and regulated transpiration tosome degree. The increases in transpiration flux resulted in a concomitant decline in leaf water potential.Under submerged soil conditions, leaf water potential in rice approached steady-state value of -1.35 MPa,possibly resulted from the changes in the plant resistance to water flow. However, under water-stressedconditions, leaf water potential continued to decline in a linear manner with increasing transpiration.
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