镉胁迫对红椿(Toona ciliate Roem.)幼苗生长及碳、氮、磷、钾累积与分配的影响

为了解镉(Cd)胁迫对红椿(Toona ciliata Roem.)生长及养分碳(C)、氮(N)、磷(P)和钾(K)]吸收的影响,采用盆栽控制试验研究了不同浓度Cd处理0(对照)、10、20、40、80、160 mg·kg~(-1)]对其幼苗生长发育、生物量以及养分积累与分配特征的影响。结果显示:与对照相比,红椿幼苗生长特性指数(如叶数、叶长、叶宽、根长及地径和株高)与根、茎、叶生物量随Cd浓度增加而降低,但低Cd处理(40 mg·kg~(-1))对各器官指数、株高及总生物量无显著影响(P0.05)。随着Cd胁迫浓度增加,根、茎、叶中Cd浓度逐渐升高,且根大于茎;根K、茎K、叶K和叶N累积量随胁迫浓度增加呈先升后降,而根C、根N、茎N、根P和叶P累积量则逐渐降低。此外,茎C、叶C和茎P在低Cd处理时无显著差异,但较高Cd胁迫处理(≥40.00 mg·kg~(-1))则显著抑制并改变其累积与分配格局。红椿幼苗具有一定的抗Cd胁迫能力,但较高浓度Cd胁迫(≥40.00 mg·kg~(-1))显著影响了红椿幼苗的生长特性及其养分格局。

Impacts of Cd stress on growth,and accumulation and distribution of C,N,P and K in Toona ciliate Roem.Seedlings

In the presented work, the effects of different Cd stress on the growth and nutrient absorption(C, N, P, and K)of Toona ciliata Roem. seedlings were investigated. A controlled pot experiment was arranged with different treatments of six Cd dosages control, 10, 20, 40, 80, and 160 mg·kg-1] to investigate the growth characteristics, biomass production and nutrient accumulation and distribution in the T. cilia-ta seedlings. The results indicated that the growth characteristic parameters(leaf growth, leaf length, leaf width, root length, base diameter, and shoot height)and tissue biomasses(i.e., root, stem, and leaf)declined with increasing Cd dosage, whereas the treatments with lower Cd dosage(<40 mg·kg-1)had no significant(P>0.05)influences on tissue index, plant height, and total biomass. Additionally, the Cd distribu-tion pattern under different Cd treatments showed the same order, with root>stem and/or root>leaf. Moreover, with increasing Cd dosage, the accumulation of root K, stem K, leaf K, and leaf N showed a trend of increase at first and then decrease, whereas accumulation of root C, root N, stem N, root P, and leaf P gradually decreased. Furthermore, the treatments with higher Cd dosages(≥40.00 mg·kg-1)significantly in-hibited the accumulation of stem C, leaf C, and stem P and altered their distribution patterns, whereas treatment with lower Cd dosages(<40 mg·kg-1)did not show significant effects. Results suggest that T. ciliata could adapt efficiently to Cd-contaminated environments by altering its nutrient use strategy and biomass distribution pattern.