荔枝生产相关的水分生理指标远程监测研究

利用植物远程监测系统对荔枝园中的大气温湿度、土壤湿度、光照强度、大气蒸汽压差(VPD)等环境因子和茎干直径微变化、果实生长、叶片温度等树体生理指标进行了监测,发现该系统能准确及时并无伤害地记录他们的实时和周期性变化。据获得的数据初步表明,当果实处于快速膨大期,主茎的加粗生长明显缓慢,一旦果实采收后,茎干加粗生长则有一个迅速上升的变化;当土壤湿度高于33%(v/v)时,主茎的生长受到明显的抑制;VPD白天上升,夜间下降,当夜间VPD始终高于0,就形成所谓的“夜间干燥”,VPD的这种变化对荔枝主茎和果实的生长以及叶气温差(LATD)都有较大的影响,如主茎和果实的日间收缩量随VPD的增大而增大,夜间空气干燥不但抑制了主茎生长,也使日最大LATD下降。据此认为,果实和茎干的生长之间存在竞争关系,土壤湿度过高或者夜间空气干燥对荔枝的生长不利。

Phytomonitoring studies on water physiological factors related to litchi production

Some environmental factors [(air temperature and humidity,solar radiation, soil moisture and vapor pressure deficit (VPD)] and physiological factors (trunk diameter micro-variations, leaf temperature, fruit growth) related to litchi production were monitored continuously with 60 min sampling interval by remote phytomonitoring measuring system ( Phytech Ltd., Irael) which could exactly record the real time and periodical changes of these indexes. The preliminary results showed that the changes of trunk diameter growth were very little during fruit rapid expanding period, and a visible acceleration of growth took place immediately after fruit harvest. A significant deceleration of trunk diameter growth was observed when the soil moisture was higher than 33% (v/v). Generally, VPD went up in the daytime and down in the nighttime, nighttime air dryness was produced while VPD was over 0 Pa in the nighttime. This VPD change had intensive effects on leaf-air temperature difference(LATD),fruit and trunk diameter variation. It was found that daily contraction of trunk and fruit diameter was increased with the rising of VPD in the daytime, but occasional air dryness at night significantly limited trunk growth and decreased the maximum daily LATD. It was suggested that there was a competitive relationship between fruit and trunk growth, and over-higher soil moisture and nighttime air dryness were not benefit to litchi growth.