| Using the method of nutrition culture, the impact of Cd stress on loquat growth, cell structure, photosynthesis were studied, the results showed as follows:1 The impact of Cd stress on cell structure of LoquatThe dissolved, disorderly-arranged epidermal cells in loquat roots wereobserved in the treatment of Cd content above 150mg/L under sand culture. Simultaneously, the gate of sieve tube in phloem were blocked, and sieve tube disappeared. Lignification became more serious with the thin vessel wall in xylem, and the vascular bundle disordered with the darken marrow. The epidermal in leaves were full of bumps and holes with stuffed of closed stomata.2 Effect of Cd stress on the growth of loquatThe obviously inhibitory to the growth of loquat were observed under serious Cd stress with the content above 300mg/L in soil culture, among which the inhibitory function became more seriously with the ascent of Cd content. The biomasses of root in 300mg/L, 400mg/L and 500mg/L reduced by 35. 75%, 38. 78%, 34. 83%, 39. 57%. The root is the most sensitive to Cd stress. Leaf ranks second, and the stem ranks third. The water content in root treated by 300mg/L, 400mg/L and 500 mg/L decreased by 9. 27mg/L, 11.78%, 12.91%, respectively compared with the control. Those of stem and leaf were 11.97%, 12.24%, 15.34% and 10.61%, 15.57%, 18.50%, respectively.3 The effects of Cd stress on permeability of plasma membrane and activity of enzymeCd stress damaged the membrane of cell in leaf. The study showed that the high concentration Cd stress caused membrane lipid peroxidation and increment of permeability of plasma membrane. The activity of SOD and POD increased with the ascent of Cd concentration, peaked at 300mg/L, with the same trend as SOD and POD.4 The effects of Cd stress on photosynthesis... |
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