不同土壤含水量下槟榔幼苗形态和生理特性

李晗 杨福孙 李昌珍 陈奇 张瀚 纠凤凤 陈才志

摘  要：為了明确土壤水分与槟榔生长之间的关系，从而确定合理的槟榔灌溉技术。以槟榔幼苗为对象，设置5个水分梯度，分别是T₁：（30±5）%、T₂：（45±5）%、T₃：（60±5）%、T₄：（75±5）%、T₅：（90±5）%，测定槟榔幼苗的形态、光合特性以及叶绿素含量和根系活力等指标。结果表明：（1）55%～65%的土壤相对含水量可以提高槟榔幼苗的株高、茎粗、叶面积和叶长，其中槟榔幼苗的株高和茎粗比在25%～35%的土壤相对含水量下分别提高了26.89%、19.89%，并且槟榔幼苗的净光合速率、蒸腾速率均达显著水平。当土壤相对含水量大于65%时，槟榔幼苗的裂叶长不断增加，但叶绿素含量逐渐降低。（2）当土壤相对含水量低于55%时，槟榔幼苗的叶绿素含量和根系活力出现下降趋势，随着土壤相对含水量的不断降低，槟榔幼苗的根冠比不断增加。（3）在30%左右土壤相对含水量下槟榔幼苗叶绿素含量达最低值11.16 mg/g，但水分利用率相对其他处理较高，植株叶片发黄且矮小，根系活力也较小。综上所述，当土壤相对含水量为55%～65%时，有利于槟榔幼苗生长。

关键词：槟榔幼苗;土壤水分;光合特性;生理特性中图分类号：S31      文献标识码：A

Morphological and Physiological Characteristics ofAreca catechu L. Seedlings under Different Soil Moisture Contents

LI Han， YANG Fusun^*， LI Changzhen， CHEN Qi， ZHANG Han， JIU Fengfeng， CHEN Caizhi

College of Tropical Crop， Hainan University， Haikou， Hainan 570228， China

Abstract： Five water gradients， T₁： （30±5）%， T₂： （45±5）%， T₃： （60±5）%， T₄： （75±5）%， T₅： （90±5）%， were used to clarify the relationship between soil moisture and areca seedlings （Areca catechu L. seedling）. The morphology， photosynthetic characteristics， chlorophyll content and root activity of the seedlings were determined. The result showed that the relative soil water content of about 55%–65% could increase the plant height， stem diameter， leaf area and leaf length. The plant height and stem diameter ratio of the seedlings increased by 26.89% and 19.89% respectively under 25%–35% relative soil water content. And the net photosynthetic rate and transpiration rate of the seedlings reached significant levels. When the relative soil water content was more than 55%–65%， the cracked leaves of the seedlings increased， but the chlorophyll content decreased gradually. When the relative soil water content was less than 55%， the chlorophyll content and root activity of the seedlings decreased. With the decrease of soil relative water content， the root-shoot ratio of the seedlings increased. The chlorophyll content of the seedlings reached the lowest value of 11.16 mg/g under 30% relative soil water content， but the water use efficiency was higher than that in other treatments. The leaves of the seedlings were yellow， and the plants were short， and the root activity was also small. In conclusion， when the relative water content in soil was 55%–65%， it was beneficial to the growth of areca seedlings.

Keywords： Areca catechuL. seedling; soil moisture; photosynthetic characteristics; physiological characters

DOI： 10.3969/j.issn.1000-2561.2020.06.009

水是植物生长发育的一个重要生境因子，植物对水分的需求是有一定限度的，过多过少都不利于植物的生长^[1]。不同植物或同一植物在不同的生长发育阶段需水量有所差异，这与植物的生长速度、生理生化活动、形态建成的快慢关系密切^[2-3]。干旱胁迫发生时，植物首先通过保持水分吸收和减少水分损失来维持体内的水分平衡，比如减少叶面积，增加根冠比等，并以渗透调节作用和细胞壁的弹性来保持一定的膨压，以保障植物在干旱条件下继续生长^[4-5]。……