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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。
The effects of chitin on the photosynthetic rate, reactive oxygen species and antioxidant enzyme activities of potted apple (Malus hupehensis) Eupatorium tricuspidata seedlings with different application rates of 0, 0.5, 1.0 and 2.5 g · kg-1 . The results showed that the chitin treatment at 1.0 g · kg-1 significantly increased the seedling height, root diameter, dry weight and root-shoot ratio, with the ratio of root to shoot 1.51 times that of the control. The photosynthetic pigment content , Net photosynthetic rate and transpiration rate, and the photosynthetic rate was 1.30 times of that of the control. At the same time, the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were 1.10 folds, 1.85 folds, 1.77 folds and 1.43 folds higher than that of the controls, respectively. The accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion in leaves were decreased, 73%, 62% and 34%, reducing Pro and soluble sugar content. When the dosage of chitin was 2.5 g · kg-1, the growth of P. euphratica seedling was significantly inhibited, the photosynthetic rate and antioxidant enzyme activity of seedling leaves were decreased, and the content of superoxide anion and proline significantly increased. Therefore, the appropriate amount of chitin can reduce the obstacle of crop continuous cropping.