白刺苗木年生长发育规律的研究

Annual Growth and Development Laws of Seedlings of Nitraria sibirica

采用Logistic曲线、幂函数、指数函数、负指数函数、Compertz模型、三次多项式等数学模型对白刺苗高与地径生长进行拟合,确定出Logistic曲线为最优模型("S"形曲线),并估测了速生期的2个拐点及其长度。结果表明:①高、径生长均符合"S"型曲线,年生长可划分为生长初期、速生期、硬化期三个时期;②白刺径生长速生期起始时间、结束时间分别比高生长晚5 d,20 d。③白刺苗高、地径生长均呈双峰型。

The growth of seedling height and ground diameter of Nitraria sibirica were fitted by adopting mathematical models, such as Logistic curve, power function, exponential function, negative exponential function, compertz model and cubic polynomial equation. Then we determined the Logistic equation for the most superior equation, and estimated respectively two inflection points and length of fast growing time of N. sibirica by adopting Logistic curve of fitting growth of seedling height and ground diameter. The results showed that： （1） height growth and diameter growth of N. sibirica accorded with ＂S＂curve, and its annual growth included three decades, which were initial stage of growth, fast-growing time and lignifications time; （2） the beginning and the end of fast-growing time of diameter growth were 5 d and 20 d respectively later than those of height growth; （3） both height growth and diameter growth had two growth peaks.