Root-promoting Growth Regulator Compositions And Their Effect On Agronomic Trait And Physiological And Biaochemical Characters Of Potatp Cuttings In Greenhouse

Potato (Solanum tuberosum L.) is a vegetative propagation crop. Continuous cultivationwill cause pathologic and physiology-biochemistry degeneration easily during the course ofthe vegetative reproduction, then lead to the decrease of the yield and the quality significantly.In order to solve the degeneration of seed tubers, virus free and rapid propagation technologyare used to reproduce mini-tubers. Cutting propagation techniques is the basis of seed potatoproduction. One of the key points in potato production is to increase propagation coefficientof mini-tuber, decrease production cost and enhance economic profit. The study researched onphysiological and biochemical effects of different plant hormones and different concentrationon virus-free potato seedlings in hope of providing theoretic basis for Potato Micro-tuberproduction. The main results were as follows:1. In order to find the the optimum prescription of plant hormones for the development ofpotato seedlings, the effect of NAA, IBA, boric acid were studied. The results of the studyshowed that the plant hormones (1) greatly improved the root growth vigor and potentials ofthe potato seedlings and increased the root protein contents of the seedlings;(2) evidentlyincreased the net photosynthetic rate, dry matter, Chlorophyll content as well as photosynthateaccumulation of the seedlings;(3) increased evidently the activity of SOD, POD, CAT and thefree amino acid content and decreased the content of MDA; and (4) significantly promotedthe potato seedlings which were better to have a mini-tuber number and yield per plant.Thereinto, with NAA at100mg/L, IBA at50mg/L and boric acid at17.5mg/L, thephotosynthetic pigment content, net photosynthetic rate, protective enzyme activity, freeamino acid content of the seedlings were the most favorable and the mini-tuber number andyield per plant appeared the highest as well.2.By means of orthogonal design of three factors and three levels, different concentrationsratio of formulations of NAA, IBA, boric acid were adopted. Compared with effects ofdifferent treatment combination on agronomic trait and physiological change, the influenceorder was as follow: NAA> IBA> boric acid. NAA concentrations is the dominant sector inenhancing growing and developing of potato seedlings, and significantly related to the various indexes. With NAA concentration100mg/kg, IBA concentration25～50mg/kg, boric acidconcentration10.5～17.5mg/kg, agronomic and physiological trait were greatly improved.According to comprehensive analysis of experimental results, the best concentration ratio is100mg/kg NAA,25mg/kg IBA and17.5mg/kg boric acid (A3B1C3). Under thisconcentration ratio (1) the root growth vigor and potentials of the potato seedlings and theroot protein contents of the seedlings were greatly improved;(2) the net photosynthetic rate,dry matter, Chlorophyll content as well as photosynthate accumulation of the seedlings wereevidently increased;(3) the activity of SOD, POD, NR and the free amino acid content wereincreased evidently, but the content of MDA were were greatly decreased at the same time;(4)the potato seedlings which were better to have a mini-tuber number and yield per plant weresignificantly promoted.