不同施磷水平对喜树幼苗生长及喜树碱积累的影响

Effects of Different Phosphorus-applying Levels on Seedling Growth and Camptothecin Accumulation in Camptotheca acuminata Seedlings

采用盆栽施肥的方法,研究了不同施磷水平(对照0 kg P·hm-2、低磷42 kg P·hm-2、中磷84 kg P·hm-2、高磷168 kg P·hm-2)对喜树当年实生幼苗生长及次生代谢物喜树碱积累的影响。结果表明:随着施磷水平的增加,喜树幼苗的苗高及叶、茎、根的干物质量均增加,且各施磷水平幼苗叶、茎、根的干物质量差异显著(p<0.05)。在不同磷素水平下,幼苗叶、根、茎中的喜树碱含量均在低磷水平时出现最大值,并且低磷水平与对照间喜树碱含量差异显著(p<0.05)。随着磷用量的增加,喜树全株及叶、茎的喜树碱总量持续增加,但喜树全株和叶在高磷与中磷水平间差异不显著。根中喜树碱总量在不同磷素水平差异显著,在中磷水平最高。由结果可知:磷可以促进喜树幼苗中喜树碱的合成,适当的低磷胁迫可以增加喜树幼苗中喜树碱含量。培育喜树碱原料林时,适宜的施磷水平应为中磷水平,幼苗喜树碱总量主要取决于喜树生物量的积累。

A potted experiment with controlled fertilization supply was conducted to study the effects of different phosphorus-applying levels（ P0,0 kg P·hm^- 2; PL,42 kg P·hm^- 2; PM,84 kg P·hm^- 2;PH,168 kg P·hm^- 2） on the growth of seedlings and camptothecin（ CPT） accumulation in C. acuminata seedlings. The experiment results showed that the height and dry weight of C. acuminata seedlings would increase when phosphorus-applying level increased. Under different levels of applying phosphorus,the dry weight of leaf,shoot and root of C. acuminata seedlings was significantly different（ p〈0. 05）.The CPT content in leaf,shoot and root reached the highest level when phosphorus-applying level was PL. Compared with P0,the CPT content in PLincreased significantly. The CPT amount in the whole seedling,leaf and shoot of C. acuminata increased gradually with the increase of phosphorus. But when phosphorus-applying level was higher than PM,the increase of CPT amount was insignificant. The CPT amount in root reached the highest level when phosphorus-applying level was PM. According to the results studied,proper deficient phosphorus stress could significantly enhance CPT content in C. acuminata seedlings. With a main objective to establish a C. acuminata seedling plantation for producing CPT,proper phosphorus level was PM. CPT amount in seedlings was mainly decided by the accumulation of biomass of C. acuminata.