遮阴和施肥对油茶幼苗叶片抗寒性的影响

以不同遮阴时间和施肥量处理的油茶幼苗为研究对象,以其叶片在不同时间(1月、2月、11月和12月)半致死温度的差异为依据,研究了油茶幼苗叶片的抗寒性对遮阴和施肥的响应。结果表明,遮阴对翌年1月和2月油茶幼苗叶片的半致死温度没有显著影响,而对当年11月和12月的半致死温度产生了显著影响。回归模拟的结果表明,当年11月和12月油茶幼苗叶片半致死温度(y)与遮阴时间(x)遵守y=ax2–bx–c(R2=0.8987*~0.9116*)模型,即此时期的半致死温度随遮阴时间增加呈现先降低后升高的变化规律,表明遮阴时间过长将会降低油茶幼苗的抗寒性。施肥对当年11月和12月及翌年1月和2月油茶幼苗叶片的半致死温度均产生了显著影响。回归模拟结果表明,不同季节,油茶幼苗叶片半致死温度(y)与施肥量(x)均遵守y=k/(1+aexp(–(bx+cx2+dx3)))(R2=0.9929*~0.9994*)模型,表明油茶幼苗叶片的半致死温度对施肥的响应呈现随施肥量增加先降低后趋于稳定的基本趋势,油茶幼苗叶片的半致死温度不随施用量的增加而无限降低。

Effects of shade and fertilization on cold-resistance of Camellia oleifera seedling leaves

Based on the difference of the semi-lethal temperature in different time (including January, February, November and December), the effects of shading time and fertilizer amount on cold resistance of Camellia oleifera seedling leaves were studied in this paper. The result showed that the shading time had a significant effect on the semi-lethal temperature of Camellia oleifera seedling leaves in November and December of the current year, but not for January and February of the next year. Regression simulation revealed that the relationship between the semi-lethal temperature (y) and shading time (x) fitted the mathematical correlation of y=ax²-bx-c (R²= 0.8987*-0.9116*), which suggested that with shading time increasing, the semi-lethal temperature dropped in the first stage and then started to increase, indicating that excessive shading time would reduce the cold resistance of Camellia oleifera seedling leaves. Fertilization obviously affected the semi-lethal temperature of Camellia oleifera seedling leaves in aforementioned four months. Regression analysis demonstrated that, for all time mentioned above, the relationship between semi-lethal temperature (y) and fertilizer amount (x) fitted the model of y=k/(1+aexp(-(bx+cx²+dx³))) (R²= 0.9929-0.9994 ), which meant that the semi-lethal temperature would gradually decrease to a plateau (instead of infinitely low) with fertilizer amount increasing.