| The purpose of this thesis was to find out the hormone control mechanism in adventitious rooting. Mung bean seedling, the ideal model plant to research the adventitious root development, was used to study the efiects of different kinds of plant growth regulator, different concentration and application phases; the change of endogenous phytohormones level during the period of adventitious rooting; and the activities of two enzymes related to IAA synthesis.I. The timing of adventitious root formationAnatomical studies showed that adventitious rooting process could be divided into four phases: induction phase(0-12h) with the cells between vascular bundle beginning to divide at the 12th hour; early initiation phase(12-24h); late initiation phase(24-48h) with the root primordim formed at the 48th hour; growth and differentiation phase(48-72h) with adventitious root becoming visible at the 72nd hour.II. The effects of plant growth regulator on adventitious rooting at different time1. EthyleneTreated with ethephon, at the range of 0-5X10?mol/L, mung bean hypocotyl cuttings formed more roots than the control, beyond the range, formed less roots than the control. Applied with 5X10?mol/L ethephon at 0-6h and 18-24h respectively, more roots were observed than other periods and the 18-24h treatment was the best; moreover at periods of 0-6h and 18-24h, 0-2h and 22-24h treatment were respectively the best. It indicated that the two periods were sensitive time period and effect of ethephon was time-dependent.ACC is the procusor of ethylene. Applied with 0-50 umol/L ACC, mung bean cuttings formed more roots and earlier than the control and the optimal concentration is 10 umol/L. Treated with 10 umol/L ACC, adventitious root number is 1.2 times as the control.AOA is an inhibitor of ACC synthase. At the range of 0-100 jamol/L rooting of mung bean hypocotyl cuttings, treated with AOA for 24h , was evidently inhibited; the higher the concentration, thestronger the inhibitory effect. The root number of cuttings, treated with 100 umol/L AOA, was sixty percent of that of the control.AgNOs is the inhibitor of the effect of ethylene. Adventitious root of mung bean cuttings, treated with 100,50 and 10 umol/L AgNOj, were respectively 1.58,2.54 and 6.64 and that of the control was 10.26. It showed that AgNCh inhibited rooting.The conclusion inferred from the above results was that ethylene promoted rooting at 0-24h(induction and early initiation phase), especially at 0-6h and ethylene's promoting rooting depended on the developmental stage.2. IAA1AA proi.ioted rooting. Mung bean hypocotyl cuttings, treated with 5X10"5 M IAA at 0-6h and 18-24h, formed more roots than other treatments; the number was respectively 11.1 and 10.9, the control was 5.8. It indicated that the two periods were sensitive to IAA and they were the same as ethylene.3. ABAThe rooting of cuttings treated with lower concentration ABA was inhibited. The base of cuttings was impaired, when it was treated with 10"5mol/L ABA or the beyond, but root number was enhanced. Root number of cutting applied with 10'3 mol/L ABA was more than that of the control, and more primodia had been formed and could not break through epidermis. Treated with 10"3 mol/L ABA at different periods during 6-3 6h, rooting was accelerated and the 6-12h treatment was the best.4. GibberellinAs same as many reports, rooting of mung bean hypocotyl cuttings was inhibited by GAi. At the range of 10"8-10"4 mol/L, the higher the concentration , the stronger the inhibitory effect. Rooting of mung bean cutting treated with 10"5 mol/L GAa at different time was inhibited, the strongest was the 0-6h( induction phase) treatment.5. Cytokinin4PU is a kind of active cytokinin and inhibited rooting of mung bean cuttings. At the range of 10"9-10"7 mol/L, the higher the concentration, the less the root number. Cutting treated with 10"7 mol/L 4PU did not form root.At 10'9-10"5 mol/L, 6-BA promoted rooting. The higher theconcentration, t...
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