Effects Of Sodium Naphthalene Acetate On Growth, Physiologicalcharacteristics And Production Of Tomato Under Suboptimal Temperature And Light Intensity

Tomato is one of the main plants cultivated in greenhouses, it is always affected by the suboptimal temperature and light during winter and early spring especially. Sodium naphthalene acetate(SNA) is involved in the process of root formation as a kind of plant growth regulator with auxin like activity. To investigate effects of sodium naphthalene acetate(SNA) on tomato growth, physiological characteristics and production under suboptimal temperature and light intensity, using tomato ‘zhongza 105’ as material, exogenous of SNA was applied to the root of tomato seedlings at the phase of three fully expanded leaves, and ten days after moving the seedlings to the phytotron which provides the condition of suboptimal temperature and light, the dry weight, photosynthesis, the activities of protective enzymes and endogenous plant hormones were tested; furthermore, using tomato “ouguan” as material, SNA(10 mg·plant-1) applied at the phase of establishment stage, the effects of root application of SNA on sunlight greenhouse tomato cultivation was studied. The results were as follows:The dry weight, vigorous seedling index, root activity, total nitrate content, net photosynthesis rate(Pn) of tomato seedlings were significantly decreased by suboptimum temperature and light intensity treatment, while catalase activity(CAT) was also reduced, and superoxide dismutase(SOD), peroxidase(POD) activity were increased, at the same time, by down-regulating relative expression of ToFZY gene and upregulating CKXs gene expression, IAA and ZR content was also decreased at different levels with temperature and light intensity decreasing.Compared with the same volume of distilled water(CK), the treatments of root application of 10、20、30 mg·L-1 exogenous SNA can increase significantly dry weight and vigorous seedling index of tomato seedlings cultured in sunlight greenhouse, and finally we chose 10 mg·L-1 SNA as the best treatment of promote the growth of tomato seedlings.Compared with the same distilled water treatment under the same environment condition, the growth, protective enzyme activity and Pn of tomato seedlings under suboptimum temperature and light intensity were increased by root application of 10 mg·L-1 SNA. Furthermore the root activity, total N content and ere also raised, IAA and ZR content were increased significantly for the upregulating ToFZY gene expression and suppressing CKXs gene expression, while ABA content was reduced.Root application of SNA at the phase of tomato establishment stage treatment can increase mean plant yield and total yield significantly, which provide technical guidance for the integrated water and fertilizer irrigation system.