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作 者 ：钱凯先, 朱浩然, 陈树谷

期 刊 ：植物生态学报 1989年 13卷 2期 页码：97-105

关键词：发菜；生态条件；水分节律；

Keywords:Nostoc flagelliforme, Ecological conditions, Rhythm of moisture,

摘 要 ：本文研究了甘肃永登和内蒙阿拉善左旗的发菜生态条件，发现了发菜生长中的水分节律现象。 发菜生于干燥的高原荒漠草原地带，属大陆性气候。其年平均气温为4.5—8℃，≥10℃积温为2231—2800℃·年，年温差大，昼夜温差明显。年平均降水量为201—290mm，集中在6—8月。年平均相对湿度为46—58%，有露水的天气约80天。土壤主要是由第三纪红土母质发育而来的棕钙土，营养贫乏，石灰质沉积明显，呈强碱性反应。年日照时数3000±300小时，辐射强烈。发菜在结构和生理上表现出强烈的旱生生态适应性，包括它的耐旱，耐贫瘠，嗜阳、嗜碱以及对温度变化的适应性强。 发菜生长中具有明显的水分节律现象。在5—10月，在暂短的降雨和露水后，藻体迅速吸取水分而得以生长。尔后，水分又很快被蒸发，藻体变干，生长停滞。发菜在这种湿润⇌干燥的反复节律中得到不断的断续生长和积累，从而完成发菜在干燥条件下的年生长过程。

Abstract:The ecological conditions of Nostoc flagelliforme in Yongdeng, Gansu and Alashanzuoqi, Neimenggu have been investigated in this paper. The water rhythm phenomenon in the growth of N. flagelliforme was discovered by us.This alga grow in desert steppes with continental climate. The mean annual temperature of such steppes should be 4.5—8℃ and the annual and daily differences in temperature are big and marked about 50℃ for the year and 15℃ for the day. The mean annual precipitation is only 201—290 mm and the mean annual relative humidity 45—58%. There are about 83 days with dewfall in one year. Therefore, the climate of such steppes is Very dry. Their soil shows a strong alkaline reaction, with pH values over 9.0 and contents of organic matters, nitrogen and phosphorus is very poor. However there is plenty of sunshine for the alga in such steppes, totalling 3000±300 hin one year.The growth of N. flagelliforme exhibits an obvious water rhythm phenomenon. From May to October, the dry alga absorbs quickly the water from rainfall or dewfall for its growth in a short duration. The water will beevaporated soon in the sunshine, and the alga will stop to grow and become dry again. The growth process of N. flagelliforme is a successive intermittent growth and accumulation in the rhythm of moisture⇌dry.

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