土壤水分对核桃楸幼苗生长和生理特性的影响

Effects of Soil Water on the Growth and Physiological Characteristics of Juglans Mandshurica Seedlings

【目的】探究不同土壤水分对核桃楸幼苗生长和生理特性的影响,为确定其苗期合理的灌溉量、实现节水栽培提供理论依据。【方法】以2 a生核桃楸幼苗为研究对象,采用盆栽试验,设置4个水分处理,供水上下限范围分别为田间持水量的80%~85%(T1)、70%~75%(T2)、60%~65%(T3)、40%~45%(T4),对核桃楸幼苗的主要生理性状和形态指标进行定期监测。【结果】从生长指标可见,随土壤含水率降低,核桃楸幼苗的地径、苗高和冠幅生长缓慢,且显著抑制了冠幅的生长(P<0.05)。土壤含水率对幼苗生长指标影响由大到小依次为:冠幅、苗高、地径,处理60 d时T1处理的冠幅增量较T4处理高了138.05%。从生理指标可见,随土壤含水率降低,核桃楸幼苗的丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性均逐渐上升,叶绿素总量逐渐减少;随土壤水分处理时间的延长,SOD、CAT、POD活性和叶绿素总量呈先上升后下降趋势,可溶性糖和MDA量逐渐上升。处理前期(15d),T4处理的MDA量迅速增加。与T3和T4处理相比,T1和T2处理的3种保护酶活性稳定地维持在较高水平。【结论】当土壤含水率为田间持水率的70%~75%和80%~85%时,核桃楸幼苗生长及生理状态良好。因此,核桃楸育苗时可将灌水下限控制在田间持水率的70%~75%以达到节水栽培的目的。

【Objective】The purpose of this paper is to explore the effects of soil water content on the growth and physiological characteristics of Juglans mandshurica seedlings to control soil water content,which provides theoretical basis for determining the reasonable irrigation amount and realizing water-saving cultivation.【Method】Two-year seedlings of Juglans mandshurica were used as research objects to monitor its physiological and morphological indexes under four water treatments(80%~85%(T1),70%~75%(T2),60%~65%(T3),40%~45%(T4))by using pot weighing to control low limit of soil water content.【Result】With the decrease of soil water content,the growth of ground diameter,height and crown of Juglans mandshurica seedlings was slow,and the growth of crown was significantly inhibited(P<0.05).The order of the influence of soil moisture content on seedlings was crown,seedling height and ground diameter,and the crown increment of T1 treatment was 138.05%higher than that of T4 treatment at 60 d.With the decreasing of soil water content,the content of malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)activity gradually increased,but the total chlorophyll content was gradually decreasing.With the increasing of treatment time,the activity of SOD,CAT,POD and the total content of chlorophyll increased first and then decreased and the content of soluble sugar and MDA increased gradually increased.In the early period of treatment(15 days),the MDA content of T4 increased sharply.Compared with T3 and T4,the activities of T1 and T2 protective enzymes were stable at a higher level.【Conclusion】When soil moisture content is 70%~75%and 80%~85%of the field water capacity,the growth and physiological state of Juglans mandshurica seedlings are good.Therefore,the lower limit of irrigation water can be controlled at 70%~75%of the field water capacity in order to achieve the purpose of water-saving cultivation.