The Relations of Stomatal Conductance, Water Consumption, Growth Rate to Leaf Water Potential During Soil Drying and Rewatering Cycle of Wheat (Triticum aestivum)

土壤乾濕循環過程中小麥葉片氣孔導度、耗水量、生長速率與葉水勢的關係

梁宗鎖(Zong-Suo Liang) ； 張福鎖(Fu-Suo Zhang) ； 邵明安(Ming-An Shao) ； 張建華(Jian-Hua Zhang)

《Botanical Bulletin of Academia Sinica》 43卷3期 (2002/07) Pp. 187-192

https://doi.org/10.7016/BBAS.200207.0187

摘要

在土壤乾濕循環過程中研究了小麥(Triticun aestivum)葉水勢與氣孔導度、生長速率和耗水量和變化，每次複水後葉水勢迅速恢復而氣孔導度表現出滯後現象，滯後時間隨乾濕交替次數增加而增加，氣孔的這種後效明顯的降低了小麥葉蒸散作用。實驗結果在緩慢乾旱後復水，小麥葉片的滲透勢明顯低於一直濕潤條件下，這有利於保持葉片膨壓而維持乾旱下小麥葉片的生長速率，使葉片生長速率快速下的葉水勢閥值降低，在相同葉水勢下經乾濕交替的小麥葉片生長速率快於未經交替脅迫的葉片，證明塌濕交替能夠誘導小麥葉片的滲透調節能力，經2-3次乾濕生氣勃勃後耗水量的下降，主要是由於氣孔導度的下降和蒸散速率的下降，並使水分利用效率提高，小麥生長速率恢復到對照水平，但總的生長小於尋照，這表明乾濕交替過程能夠對小麥生長、氣孔行爲、耗水過程産生後效，同時能夠使根冠比增加。

關鍵字

葉水勢 ； 耗水量 ； 生長 ； 乾旱 ； 小麥

並列摘要

The wheat, Triticum aestivum, was used to study the relationships among stomatal conductance, water consumption, and growth rate to leaf water potential during a soil drying and rewatering cycle. Stomatal conductance of wheat steadily decreased with decreases in the days of drying and leaf water potential. Upon rewatering, leaf water potential rapidly returned to the control levels, whereas the reopening of stomata showed an obvious lag time. The length of this lag time was highly dependent on times of the drying and rewatering cycle. The result proved that the drying-rewatering alternation had a significant aftereffect on wheat stomata that could reduce wheat transpiration. The results of the trial showed that the slowly intensified soil water deficiency and the following recovery of soil moisture could decreased the osmotic regulation of wheat, keep wheat leaves turgid and growing under water deficient conditions, and decrease the threshold of leaf water potential below which wheat growth would slow much more rapidly. The fact that, at the same leaf water potential, the wheat growth rate after the recovery of soil moisture was higher than before indicates that the osmotic regulation induced by the drying and rewatering alternation could keep wheat growing and wheat soil water use efficiency significantly increasing under drought conditions. The decreased wheat water consumption mainly resulted from the decreased stomata conductance and transpiration rate. During the recovery of soil moisture, the transpiration through stomata, although wheat growth rate was able to return to normal, did not completely recover. This showed that the drying and wetting alternation had after-effects on wheat growth. Meanwhile, the drying and rewatering alternation increased the ratio of root dry weight to shoot dry weight.

並列關鍵字

Drying ； Growth ； Leaf water potential ； Water consumption ； Wheat