Metcalfe J C, Davies W J, Pereira J S
Institute of Environmental and Biological Sciences, University of Lancaster, Lancaster LA1 4YQ, U.K.
Tree Physiol. 1990 Jun;6(2):221-7. doi: 10.1093/treephys/6.2.221.
Eucalyptus globulus Labill. seedlings grown under field conditions in Portugal were watered either daily (control) or every 6 days (drought-treated). Relative to those of control plants, rates of leaf production and leaf biomass accumulation were reduced by almost half in drought-treated plants. However, whereas expansion of new leaves on control plants slowed toward the end of the 30 day experiment, expansion of leaves of the same age on drought-treated plants accelerated as a change in weather conditions resulted in midday plant water potentials above -3.0 MPa. In plants that were left unwatered until they wilted and were then watered daily, expansion of the fifth leaf pair from the apex was slower than that of the same pair of leaves of plants watered daily throughout; but it continued for about twice as long and resulted in the same final leaf area. Drought treatment also caused a substantial reduction in the rate of leaf production, which, in part, accounted for the effect of drought on leaf biomass production. In a greenhouse study, witholding water for 15 days had only a slight effect on the length or width of adaxial epidermal cells, and the effect was quickly reversed on rewatering.
在葡萄牙田间条件下生长的蓝桉幼苗，要么每天浇水（对照），要么每6天浇水一次（干旱处理）。与对照植株相比，干旱处理植株的叶片产生速率和叶片生物量积累速率降低了近一半。然而，在为期30天的试验结束时，对照植株新叶的扩展速度减缓，而由于天气条件变化导致午间植株水势高于-3.0兆帕，干旱处理植株相同年龄叶片的扩展加速。在一直不浇水直至枯萎然后每天浇水的植株中，从顶端数第五对叶片的扩展速度比整个试验期间每天浇水的植株中同一对叶片的扩展速度慢；但扩展持续的时间约为后者的两倍，最终叶面积相同。干旱处理还导致叶片产生速率大幅降低，这在一定程度上解释了干旱对叶片生物量产生的影响。在一项温室研究中，停水15天对近轴表皮细胞的长度或宽度只有轻微影响，复水后这种影响很快逆转。
