甲壳素对连作平邑甜茶生长、光合及抗氧化酶的影响

以苹果连作土盆栽的平邑甜茶幼苗为试材,探讨了0、0.5、1.0和2.5 g·kg-1不同施入量的甲壳素对其光合速率、活性氧含量及抗氧化酶活性的影响。结果表明,1.0 g·kg-1的甲壳素处理能显著促进幼苗株高、地径,干样质量和根冠比的增加,根冠比为对照的1.51倍;明显提高了幼苗叶片光合色素含量、净光合速率和蒸腾速率,其中光合速率为对照的1.30倍;同时提高了幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,分别为对照的1.10倍、1.85倍、1.77倍和1.43倍;减少了叶片丙二醛(MDA)、过氧化氢(H2O2)和超氧阴离子的积累,分别为对照的73%、62%和34%,降低了脯氨酸(Pro)和可溶性糖含量。当甲壳素施用量为2.5 g·kg-1时则显著抑制平邑甜茶幼苗生长,降低幼苗叶片光合速率和抗氧化酶活性,并使超氧阴离子和脯氨酸含量明显上升。因此,适宜用量的甲壳素能减轻苹果的连作障碍。

Effects of Chitin on Growth,Photosynthesis and Antioxidative System of Malus hupehensis Seedlings Under Replant Condition

Chitins were added to the replant soils in pots to the final dosages at 0，0.5，1.0，2.5 g ? kg-1，respectively. The seedlings of Malus hupehensis Rehd. were planted in the pots. The effects of chitin on the photosynthesis，the contents of reactive oxygen species（ROS）and the activities of antioxidative enzymes in leaves of Malus hupehensis Rehd. seedlings under the replant conditions were studied. The results showed that the addition of chitin at 1.0 g ? kg-1 obviously enhanced the plant height，ground diameter，up and under ground dry weight，root shoot ratio and photosynthetic parameters. The root shoot ratio of plants treated with 1.0 g ? kg-1 chitins was 1.51 higher than that of the control. Treatment with 1.0 g ? kg-1 chitins also increased the content of photosynthetic pigments，net photosynthetic rate（Pn） and transpiration rate（Tr）in leaves of seedlings. The Pn of plants treated with 1.0 g ? kg-1 chitins was 1.30 higher than that of the control. The seedlings treated with 1.0 g ? kg-1 chitin exhibited higher activities of antioxidant enzymes including superoxide dismutase（SOD），peroxidase（POD），catalase（CAT），and ascorbate peroxidase（APX），which were 1.10，1.85，1.77 and 1.43 times as high as that of the control，respectively. Treatment with 1.0 g ? kg-1 chitin not only decreased the contents of MDA，H2O2，and  to 73%，62% and 34% of the control，but also reduced the contents of proline（Pro）and soluble sugars. Addition of chitin at 2.5 g ? kg-1 significantly decreased the biomass，photosynthetic rate and the activities of antioxidant enzymes，promoted the accumulation of the  and proline. Those results suggested that appropriate dosages of chitin could alleviate the replant disease of apple.