不同剂量稀土对金雨金合欢幼苗生长的影响

为明确稀土对金雨金合欢幼苗生长的影响,采用8种不同剂量的稀土对金雨金合幼苗进行根施。结果表明:1)金雨金合欢幼苗施入稀土后,7～10d起幼苗形态出现不同的变化,比对照出现相同反应提早5～6d;2)90d的各项测定生长指标分析表明,每株施入0.05～1.00g剂量稀土,对幼苗生长具有较好的促进作用,其幼苗高、地径净增长,全苗鲜、干重量,叶片总面积,根系总长度、根系表面积和根尖数量总体上呈有规律的增长趋势,均显著高于对照(P<0.05),以施入剂量0.25g·株^-1处理表现最好,其苗木出圃率达到100%,与对照相比,苗高、地径净增长了204.0%和102.0%,叶片总面积、根系总长度、根系表面积和根尖数量分别增长了976%、339%、405%和187%,全苗鲜、干重量,提高了61.5%和133.3%;3)当施入剂量超过2.00g·株^-1时,苗木生长开始受抑,出现"毒害"反应,其各项生长指标下降,部分苗木死亡,并随剂量增大,生长受抑程度加剧,生长指标下降速度增大,幼苗死亡数量增多。表明低浓度的稀土溶液根施,对金雨金合欢幼苗生长具有促进作用,高浓度则抑制了其生长,甚至会导致死亡。

Effects of Different Doses of Rare Earth Elements on the Growth of Acacia adunca Seedlings

In order to understand the effects of rare earth elements on the growth of Acacia adunca seedlings,8 different doses of rare earth were applied in the soils in which A.adunca seedlings were cultivated.The results were as follows.1) The variation of seedling morphology occurred 7 to 10 days after the application,5-6 days earlier than the control.2) The growth indices of the seedlings that were measured at the 90 th day after the application indicated that doses of 0.05-1.00 g per seedling could promote the seedling growth.Physiological parameters such as the seedling height,basal diameter,fresh weight,drought weight,leaf area,root length,root surface area and number of root tips increased regularly,and significantly higher than those of the control ( P <0.05).The best dose of application was 0.25 g per seedling,from which the net growth of height and basal diameter,leaf area,root length,root surface area and root amounts increased by 204.0%,102.0%,976%,339%,405%,and 187%,respectively compared to the control.Fresh weight and drought weight increased by 61.5% and 133.3%.3) When the doses were more than 2.00 g per seedling,the seedling growths were inhibited,and all the growth indices decreased,some seedlings even died.With the increase of application dose,the inhibition intensified,the growth indices declined significantly,the rate of seedling death increased.In conclusion,low dose of rear earth application could promote the growth of A.adunca seedlings,and high dose could inhibit the seedling growth.