不同施肥处理对桂花品种‘浦城丹桂’幼苗生长和生理的影响及施肥成本分析

Effect of different fertilizer treatments on growth and physiology of Osmanthus fragrans ‘Pucheng Dangui' seedling and analysis on fertilizer cost

采用L9(33)设置3因素(包括氮、磷和钾肥)3水平(N单株施用量分别为0、10和20 g,P2O5单株施用量分别为0、4和8 g,K2O单株施用量分别为0、6和12 g)正交实验,在2015年3月和4月分2次施肥,对9个施肥处理组施肥前后2年生桂花品种‘浦城丹桂’(Osmanthus fragrans‘Pucheng Dangui’)幼苗的生长和生理指标进行测定;并采用Pearson相关性分析法和回归分析法分别对各指标间的相关性以及各生长指标与施肥成本的关系进行分析。结果表明:与对照组(N、P2O5和K2O单株施用量均为0 g)相比,各处理组幼苗的株高和地径增长量及全株干质量总体上显著提高(P<0.05)。3月份至10月份,各处理组幼苗叶片的叶绿素a(Chla)和叶绿素b(Chlb)含量总体呈先升高后降低的变化趋势,并在12月份明显升高;而施肥后(6月份至12月份)各处理组叶片的Chla/Chlb比值总体呈先降低后升高的变化趋势,并且在12月份显著高于对照组。施肥后,各处理组叶片的SOD和POD活性及可溶性蛋白质含量也呈先高后低的变化趋势。相关性分析结果表明:施肥后,全株干质量与株高增长量和地径增长量呈极显著正相关(P<0.01),并与POD活性呈显著负相关;株高增长量与地径增长量和Chla/Chlb含量比值分别呈极显著和显著正相关;Chla含量与Chlb含量和可溶性蛋白质含量分别呈极显著和显著正相关。回归分析结果表明:单株施肥成本与幼苗的株高增长量和地径增长量及全株干质量均呈线性关系,且均呈极显著正相关;其中,A8(N、P2O5和K2O单株施用量分别为20、8和6 g)和A7(N、P2O5和K2O单株施用量分别为20、4和0 g)处理组的幼苗生长指标较高且差异不明显,但A8处理组的单株施肥成本高于A7处理组。研究结果表明:氮、磷和钾肥合理配施能够有效调节‘浦城丹桂’幼苗叶片的光合色素含量和抗氧化酶活性,并可促进幼苗生长。综合考虑施肥成本和生长指标,单株分别施用N和P2O520和4 g较适宜‘浦城丹桂’幼苗的生长。

Orthogonal experiment with three factors （including nitrogen, phosphorus and potassium fertilizers） and three levels （ applying amount per plant of N was 0 , 10 and 20 g, respectively, that of P2O5 was 0 ,4 and 8 g, respectively, that of K2O was 0 , 6 and 12 g, respectively） was set up by L9（3^3）, and fertilized at two separate times in March and April,2015. Growth and physiological indexes of two- year-old seedling of Osmanthus fragrans ‘ Pucheng Dangui ’ in nine fertilizer treatment groups before and after fertilization were determined. And correlations among different indexes and relationship of different growth indexes with fertilizer cost were analyzed by Pearson correlation analysis and regression analysis methods, respectively. The results show that compared with the control group （all of applying amount per plant of N , P2O5 and K2O is 0 g ）, increments of seedling height and ground diameter, and dry weight of whole plant of seedling of different treatment groups all generally increase significantly （ P 〈0. 05）. During March to October, contents of chlorophyll a （Chla） and chlorophyll b （Chlb） in leaf of seedling of different treatment groups generally appear the changing trend of firstly increasing and then decreasing, and obviously increase in December, while after fertilization （ during June to December） , Chla/Chlb ratio in leaf of different treatment groups generally appears the changing trend of firstly decreasing and then increasing, and that in December is significantly higher than that of the control group. After fertilization, activities of SOD and POD, and content of soluble protein in leaf of different treatment groups also appear the changing trend of firstly increasing and then decreasing. Correlation analysis result shows that after fertilization, there are extremely significantly positive correlations of dry weight of whole plant with increments of seedling height and ground diameter （ P 〈0. 01 ） , and significantly negative correlation with POD activity; there are extremely significantly and significantly positive correlations of increment of seedling height with increment of ground diameter and Chla/Chlb ratio, respectively; and there are extremely significantly and significantly positive correlations of Chla content with contents of Chlb and soluble protein, respectively. Regression analysis result shows that there are linear relationships of fertilizer cost per plant with increments of seedling height and ground diameter and dry weight of whole plant of seedling, and all of them appear extremely significantly positive correlation. In which, growth indexes of seedling in A8 （applying amount per plant of N , P2 O5 and K2 O is 20, 8 and 6 g , respectively） and A7 （ applying amount per plant of N , P2 O5 and K2 O is 20, 4 and 0 g , respectively） treatment groups are higher with no significant difference, but fertilizer cost per plant of A8 treatment group is higher than that of A7 treatment group. It is suggested that properly applying nitrogen, phosphorus and potassium fertilizers can effectively regulate photosynthetic pigment content and antioxidant enzyme activity in leaf of ‘ Pucheng Dangui ’ seedling, and can promote growth of seedling. Comprehensively considering fertilizer cost and growth indexes, respectively applying 20 and 4 g per plant of N and P2O5 is suitable to growth of ‘ Pucheng Dangui’ seedling.