扦插时间对蝟实插穗生根率和相关指标的影响及生根效应综合评价

在3月5日至9月5日期间,以蝟实( Kolkwitzia amabilis Graebn.)顶端枝条作为插穗,每隔10 d扦插1次,对扦插10 d后插穗的生根率,内源吲哚乙酸( IAA)、脱落酸( ABA)和赤霉素( GA3)含量,超氧化物歧化酶( SOD)、过氧化物酶( POD)和过氧化氢酶( CAT)活性以及可溶性糖和可溶性蛋白质含量进行比较,对生根率与上述8项指标进行相关性分析和回归分析,并对这8项指标进行主成分分析；在此基础上,对不同扦插时间插穗的生根效应进行隶属函数值分析和综合评价。结果显示：随扦插时间推移,蝟实插穗的生根率总体上呈现先升高后降低的变化趋势,5月下旬至7月中旬期间扦插的插穗生根率相对较高,并以6月中旬至7月中旬期间扦插的插穗为最高,总体在70%以上。随扦插时间推移,插穗中IAA和可溶性糖含量均呈波动变化趋势；而插穗中的ABA含量、POD活性和可溶性蛋白质含量总体呈先逐渐升高后逐渐降低的趋势,GA3含量和CAT活性变化不明显,SOD活性总体上呈缓慢升高的趋势。相关性分析结果表明：蝟实插穗的生根率与IAA含量、POD活性和可溶性蛋白质含量呈极显著(P<0.01)正相关,与CAT活性呈极显著负相关。主成分分析结果显示：前2个主成分的累计贡献率为84.383%,说明前2个主成分能够基本反映蝟实扦插生根的主要影响因子,其中第1主成分中可溶性蛋白质和IAA含量为主要因子,第2主成分中CAT活性为主要因子。综合评价结果显示：5月下旬至7月中旬期间扦插的蝟实插穗的综合评价指数(D)较高,为0.747~0.983,与插穗生根率的实测值基本吻合。研究结果表明：在中国西北地区,蝟实插穗的适宜扦插时间为5月下旬至7月中旬,并以6月中旬至7月中旬为最佳；扦插过程中喷施适当浓度IAA溶液可以提高插穗的生根率。

Effect of cutting time on rooting rate and related indexes of cuttings of Kolkwitzia amabilis and ;comprehensive evaluation on rooting effect

During the period from March 5th to September 5th, taking top branches of Kolkwitzia amabilis Graebn. as cuttings, cutting one time every 10 d, rooting rate, contents of endogenous indoleacetic acid ( IAA) , abscisic acid ( ABA ) and gibberellin ( GA3 ) , activities of superoxide dismutase ( SOD ) , peroxidase ( POD) and catalase ( CAT) , contents of soluble sugar and soluble protein in cuttings after cut for 10 d were compared, and correlation analysis and regression analysis on rooting rate with above eight indexes were carried out, also, principal component analysis on these eight indexes was carried out. On this basis, subordinate function value analysis and comprehensive evaluation on rooting effect of cuttings at different cutting times were carried out. The results show that along with cutting time, rooting rate of cuttings of K. amabilis generally appears the changing trend of firstly increasing and then decreasing, that of cuttings is relatively high during the period from the last ten-day of May to the middle ten-day of July, and that is the highest during the period from the middle ten-day of June to the middle ten-day of July generally with a value of above 70%. Along with cutting time, contents of IAA and soluble sugar in cuttings appear fluctuant changing trend. While, ABA content, POD activity and soluble protein content generally appear the trend of firstly increasing gradually and then decreasing gradually, changes in GA3 content and CAT activity are not obvious, and SOD activity generally appears the trend of increasing slowly. The correlation analysis result shows that there are extremely significantly (P<0. 01) positive correlations of rooting rate of cuttings of K. amabilis with IAA content, POD activity and soluble protein content, and extremely significantly negative correlation with CAT activity. The principal component analysis result indicates that cumulative contribution rate of the first two principal components is 84 . 383%, meaning that the first two principal components can basically reflect the main affecting factors for rooting of cuttings of K. amabilis, in which, contents of soluble protein and IAA are main factor in the first principal component, and CAT activity is main factor in the second principal component. The comprehensive evaluation result shows that comprehensive evaluation index ( D ) of cuttings of K. amabilis is high with a value of 0. 747-0. 983 during the period from the last ten-day of May to the middle ten-day of July, which is basically identical with measured value of rooting rate of cuttings. It is suggested that in the northwest of China, appropriate cutting time of cuttings of K. amabilis is the period from the last ten-day of May to the middle ten-day of July, and the period from the middle ten-day of June to the middle ten-day of July is the best. In cutting process, spraying appropriate concentration of IAA solution can improve rooting rate of cuttings.