镉胁迫条件下磷肥对结缕草光合特性的影响

采用盆栽试验,研究镉(50 mg·kg-1)胁迫下不同磷肥水平(50、100、150 mg·kg-1)对结缕草生长及光合特性的影响。结果表明,镉胁迫下结缕草的生长和光合特性受到抑制,施加100 mg·kg-1磷肥的结缕草叶长比只受镉胁迫组增加53.33%,根长增加70.5%,叶绿素a+b含量增加42.85%,净光合速率(Pn)增加54.75%,蒸腾速率(Tr)增加94.05%,水分利用效率(WUE)增加45.85%,PSⅡ原初光能转化效率(Fv/Fm)增加12.84%,且与镉胁迫组差异显著。施加150 mg·kg-1磷肥结缕草叶片的胞间二氧化碳浓度(Ci)、表观光电子传递效率(ETR)比镉胁迫组降低。除气孔导度(Gs)在50 mg·kg-1磷肥处理后显著增加,结缕草叶长、根长、叶绿素含量、Pn、Tr、Fv/Fm、Ci和ETR等指标均随磷肥浓度增加呈现先增加后减少的趋势。通过结缕草生长和光合指标可以看出,施用磷肥可以缓解镉对结缕草的胁迫,施加100 mg·kg-1磷肥效果显著。

Effect of phosphorus on physiological and photosynthetic characteristics of Zoysia japonica under cadmium stress

Effect of phosphorus (50, 100, 150 mg·kg-1 ) on the growth and photosynthetic characteristics of Zoysia japoni-ca under cadmium stress (50 mg·kg-1 cadmium) was studied in this research. The result showed that the growth and photo-synthesis of Zoysia japonica were inhibited by cadmium stress. When applied 100 mg·kg-1 phosphate fertilizer on Zoysia ja-ponica, the leaf length increased 53. 33%, root length increased 70. 5%, chlorophyll a+b content increased 42. 85%, net photosynthetic rate ( Pn ) increased 54. 75%, transpiration rate ( Tr ) increased 94. 05%, water use efficiency ( WUE) in-creased 45. 85%, PSⅡ primary light energy conversion efficiency ( Fv/Fm ) increased 12. 84%, and had significant differ-ence compared to cadmium stress treatment. Compared with cadmium stress treatment, intercellular CO2 concentration (Ci), tourism electronic transfer efficiency ( ERT) decreased in the treatment with 150 mg·kg-1 phosphate fertilizer. Besides stomatal conductance (Gs) increased significantly with increasing of phosphate fertilizer, the leaf length, root length, Pn, Tr, Fv/Fm, Ci , ETR increased firstly and then declined with phosphorus concentration increase. It indicated that phosphate fertilizer regula-ted growth and photosytnthetic indexes of Zoysia japonica under cadmium stress, and the application level of 100 mg·kg-1 per-formed best.