苹果树水分状况及其与蒸腾光合的关系

本文以二年生盆栽苹果(辽伏)为材科研究了叶水势与相对含水量的关系及其日变化动态;叶水分状况与蒸騰强度及光合强度的关系。研究结果表明: 叶水势最低值(-26.4巴)出现在10时,叶水势最高值(-22.7巴)出现在第二天的6时。不同部位叶水势不同。同一枝条不同节位叶水势为:下位叶<中位叶<上化叶。同一树冠外围叶水势为:下部叶>中部叶>上部叶。树冠内膛和外围叶水势为:内膛叶水势>外围叶水势。黎明时、日出时叶水分状况与白天的蒸騰强度的关系达到极显著的水平。日出后(10时)叶水分状况与蒸騰强度的关系有前者那样显著,但都表现出一定的阈值效应。

ON ANALYSIS OF LEAF WATER POTENTIAL, LEAF RELATIVE WATER CONTENT, TRANSPIRATION AND PHOTOSYNTHESIS OF FRUIT TREES

Pot-cultured apple trees of two-yr old were used to study therelationship between leaf relative water content and leaf waterpotential, leaf water potential diurnal, and the relationshipbetween leaf water status and transpiration, photosynthesis. Leafwater potential reached a minimum value (-22.7 bars) at 10.00 p.m.and maximum value (-22.7 bars) at 6.00 a.m. the next day, There was a variation of leaf water potential at different partsin a plant. The leaf water potential of the middle part of a shootwas lower than that of the upper and leaf water potential of thebottom was the lowest. On the outside of a crown, leaf waterpotential of the middle was lower than that of the bottom and thatof the upper was the lowest. Leaf water potential of the outsidewas lower than that of the inside at the same height of a crown. The relationship between leaf water status and transpiration rate atdawn and sunrise was more significant than that at 10.00. They alldemonstrated a threshold effect, but there were variations amongdifferent variaties and species, even the same species at differenttime.