库尔勒香梨树体生长与15N的吸收及分配动态

Growth, 15N absorption and 15N distribution dynamics in Korla fragrant pear trees

为给库尔勒香梨园合理施肥及氮肥利用率的提高提供参考,以6年生库尔勒香梨为研究对象,采用15N同位素示踪技术,研究萌芽前期至果实成熟期库尔勒香梨树体生长和氮素吸收、分配动态。结果表明:库尔勒香梨树体基径随着生育期的推移逐渐增大,于果实成熟期达到最大(8.71cm);库尔勒香梨叶片的叶面积指数、叶绿素SPAD值和叶片光合速率均随着香梨年生育期的推进呈现先增大后减小的趋势,均在第2个快速膨大期达到最大,分别为2.40、42.03和12.50μmol/(m^2·s);在年生育末期,库尔勒香梨单株树体的生物量为19958g,氮素积累量为199.44g,各器官中以当年新生器官果实的生物量和氮素积累量为最高,分别占整株树体生物量和氮素积累量的33.33%和25.08%。不同生育期15N在树体内的运转随生长中心的变化而变化。盛花期15N在1年生枝中的分配势最强,新梢旺长期和第2个快速膨大期15N在叶片中的分配势最强,果实成熟期15N在果实中的分配势最强。在果实成熟期库尔勒香梨树体当季15N肥料利用率为17.35%。

In order to provide some references for rational fertilization and increasing nitrogen fertilizer utilization rate in Korla fragrant pear garden,six-year-old Korla fragrant pear trees were used as research objects,and growth,nitrogen absorption and nitrogen distribution dynamics in Korla fragrant pear trees were researched from early bud stage to fruit mature stage by using the 15N isotope tracing technique.The results showed that basal diameter of Korla fragrant pear tree was gradually increased with development of growth period,and reached the maximum value (8.71 cm) at fruit mature stage.With development of growth stage,leaf area index,chlorophyll SPAD value and photosynthetic rate in Korla fragrant pear leaves all showed the trend of increasing firstly and then decreasing.They reached the maximum values at the second fruit expansion stage,which were 2.40,42.03 and 12.50 μmol/(m^2·s),respectively.At the end of annual growth stage,single tree biomass in Korla fragrant pear was 19 958 g,nitrogen accumulation was 199.44 g.Biomass and nitrogen accumulation in the new organ fruits were the highest among each organ,which accounted for 33.33% and 25.08% of whole tree,respectively.Migration of 15N in trees was changed with change of growth center at different growth stages. Distribution potential of 15N in current branches was the strongest at full-bloom stage,distribution potential of 15N in leaves was the strongest at fast growing stage of new shoot and the second fruit fast expansion stage,and distribution potential of 15N in fruits was the strongest at fruit mature stage.15N fertilizer utilization rate of Korla fragrant pear tree was 17.35% at fruit mature stage.