几种紫胶虫优良寄主树的自然分布概况及耐旱性与水分生理

从六种紫胶虫优良寄主树钝叶黄檀、思茅黄檀、瓦氏葛藤、大叶千斤拔、山合欢、聚果榕的自然分布与生态特性看出，它们均为耐旱性较强的树种。进一步测定其蒸腾强度、水势、水分饱和亏等水分生理指标发现，蒸腾强度与水势受气温、空气相对湿度、光照和风速等综合气候因素的影响。蒸腾强度随气温、光照强度、风速的增大而增高，随相对湿度的增大而降低；水势的变化则正好相反。蒸腾强度增大，水势下降，被动吸水能力随之增强，抗旱能力增强。植物体内的临界饱和亏越大，需水程度就越小，抗干旱能力越强。测定结果反映出，六种紫胶虫优良寄主树种的抗旱性由强到弱依次为：山合欢，钝叶黄檀，瓦氏葛滕，思茅黄檀，大叶千斤拔，聚果榕。

Natural Distribution,Drought-resistant Nature and Moisture Physiology of Fine Host Trees for Lac Insects

Study on natural distribution and biological characters of fine host trees of lac insects have shown that six species of trees, Albizzia kalkora,Dalbergia obtusifolia,D.szemaoensis,Pueraria wallichii,Moghania macrophylla,Ficus racemosa ,are fine drought resistant species of trees. Their moisture physiology indexes such as strength of transpiration,water potential,and water saturation deficit etc. relate to comprehensive climate factors,for example,atmospheric temperature,intensity of illumination,relative humidity of atmosphere,wind velocity etc. The strength of transpiration increased with the rise of temperature,intensity of illumination and wind speed,or decreased with the rise of relative humidity of atmosphere. Variations of water potential are just contrary to the change of strength of transpiration. The water potentials dropped when the strength of transpiration raised,and the capability to absorb water passively increased,and the ability of drought resistance is raised too.The bigger the critical saturation deficits in plant frame,the smaller the water requirement and the stronger the drought hardiness. The results have shown that the drought resistance of the 6 spacies of trees is arranged in order from stronger to weaker as follows: A. kalkora,D.obtusifolia,P.wallichii,D.szemaoensis,M. macrophylla,F.racemosa.