西兰花苗期生长模型的拟合和分析

Growth model fitting and analysis of broccoli seedlings

为研究西兰花苗期生长规律及物候期参数和生长参数特征,以台绿1号西兰花为材料,对西兰花苗期的生长状况进行连续观察,并用Logistic方程分别对株高、茎粗、鲜质量和干质量的生长动态过程进行拟合,获得Logistic生长模型、物候期与生长特征参数。结果表明,西兰花幼苗不同生长指标的生长变化规律基本一致,符合S型生长曲线,拟合方程的决定系数均达到0.981以上;各指标在播种后8 d陆续进入速生期,播种后33 d陆续进入缓增期,速生期的线性生长量占总生长量的60%以上;依S型生长曲线特点和西兰花幼苗生长特点将苗期分为渐增期、速生期和缓增期;模型验证表明,台绿1号西兰花苗期生长模型具有较好的可靠性。用Logistic方程可以拟合西兰花幼苗的生长动态,建议在幼苗速生期（播种后20~33 d）加强肥水管理,在苗龄33 d（四叶一心）时进行移栽定植。

With broccoli variety Tailu No. 1 as materials,the growth status of broccoli seedlings was observed continuously. The growth dynamic processes of plant height,stem diameter,fresh weight and dry weight were fitted by Logistic equation,and the Logistic growth model,phenology and growth characteristic parameters were obtained. The results showed that the growth variation regularity of broccoli seedlings in different growth indicators are basically the same,in line with S-shaped growth curve,and the coefficient of determination（R2） was more than 0. 981. Each index entered the fast growth period and the slow growth period on 8 d and 33 d after sowing,respectively. Linear growth of the fast growth period accounted for more than 60% of the total amount of growth. According to the Logistic curve,three phases of accelerating growth,fast growth and slow growth were accurately divided during broccoli seedling period. The correlation coefficient of the model validation indicated the reliability of broccoli seedling growth model. By using the Logistic equation,the dynamic growth of broccoli seedlings could be fitted. The fertilizer and water management should be strengthened in fast growth period of seedlings（20-33 d after sowing）; and the transplantation should be carried out on 33 d with four leaves.