供磷水平对杉木根表铁膜含量及幼苗生长的影响

Effect of phosphorus supply on root iron plaque and growth of Cunninghamia lanceolata seedling

为了探究不同供磷水平下杉木根表铁膜的形成情况,以及供磷水平与幼苗生长和磷素积累的关系,以同一杉木无性系幼苗作为试验材料进行室内沙培盆栽模拟试验,设置两种磷胁迫处理,分别为处理1(0 mmol·L^(-1)KH_(2)PO_(4))和处理2(0.5 mmol·L^(-1)KH_(2)PO_(4)),对照为正常供磷处理(CK,1.0 mmol·L^(-1)KH_(2)PO_(4)).测定不同处理时间内(10和20 d)参试杉木幼苗根表铁膜含量以及生物量、根系形态、根系和地上部磷素积累量的变化情况.结果表明:经过10 d处理,CK和处理2的参试幼苗根系生物量均大于处理1,但根表铁膜含量和根系磷素积累量则表现为CK显著高于处理1和处理2.试验处理20 d后,CK和处理2的铁膜含量以及根系磷素积累量均显著高于处理1.与处理10 d相比,处理2的杉木根系在处理20 d后出现了明显生长,其根长、根表面积、根系磷素积累量分别增长27.34%、48.79%、91.96%.处理20 d时,处理1、处理2以及CK的根表铁膜含量相比于处理10 d分别增长了23.61%、183.85%、11.27%.表明参试幼苗的根表铁膜含量与根长、根表面积、生物量以及根系和地上部磷素积累量均呈现显著正相关关系.可见,杉木幼苗的根表铁膜含量会随着时间的延长而提高,处理2对杉木幼苗根表铁膜形成有着明显的促进作用,进而增加了杉木幼苗根系和地上部磷素的积累,增强其抵抗磷胁迫环境能力.

The study explored the formation of iron plaque(IP)on the root surface of Cunninghamia lanceolata seedlings under different Phosphorus(P)supply levels and its relationship with seedling growth and P accumulation,so as to provide a basis for the further investigation of the adaptive strategy of C.lanceolata under low P condition in red soil areas.C.lanceolata clone seedlings were divided into 3 groups treated with various P supplies,namely treatment 1(0 mmol·L^(-1) KH_(2)PO_(4)),treatment 2(0.5 mmol·L^(-1) KH_(2)PO_(4)),and normal P supply(1.0 mmol·L^(-1) KH_(2)PO_(4))as the control(CK).The content of root IP,biomass,root morphology,and P accumulation in the root and shoot of C.lanceolata seedlings were measured and compared after different treatment times(10 and 20 d).The results showed that root biomass in the CK and treatment 2 were numerically greater than that in treatment 1 after 10 days of treatment,while root IP content and P accumulation were significantly higher in the CK than other treatments.After 20 days of treatment,root IP content and P accumulation in CK and treatment 2 were significantly higher than those in treatment 1.And the root of C.lanceolata seedlings in treatment 2 showed obvious growth with increased length,surface area and P accumulation by 27.34%,48.79%and 91.96%,respectively compared with the growths at 10 d.Meanwhile,the root IP contents in treatment 1,2 and CK were increased by 23.61%,183.85%and 11.27%,respectively at 20 d than those at 10 d.The root IP was positively correlated with root length,root surface area,biomass and P accumulation in the root and shoot.In conclusion,the root IP of C.lanceolata seedlings increased with time.Treatment 2 significantly promoted the formation of root IP,which increased P accumulation in the root and shoot,thus enhancing the resistance of C.lanceolata seedlings to environmental P stress.