| Aquilaria sinensis (Lour.) Gilg, a tropical and subtropical evergreen broad leave tree species, is an unique rare medical plant in China. It had been listed as the state-protected the third class rare and endangered plants, meanwhile it was the second class protected wild plant by the state. In order to propagate, conserve and develop the resources, five experiments on cutting propagation were carried out. The experiments dealed with the culture substrate, plant growth regulators and concentration treatments, the cutting's parts, styles of keeping leaves and planting seasons, meanwhile the rooting mechanism of A. sinensis was studied by changing of contents of endogenous hormones and nutrients, as well as oxidation enzymes activity.The main results were as follows:1) The mixture substrate of yellow subsoil, peat soil and vermiculite (3:2:1 v/v) was the best to promote rooting of the semi-lignified cuttings. The rooting of cuttings was significantly influenced by types and concentration of plant growth regulators. The rooting capability of cuttings of IBA treatment was higher than that of IAA, NAA and ABT1# treatments. The general rooting effectiveness of cuttings with IBA 1500mg·L-1 was the best by multi-indices assessment. ABT1# can obviously remedy cuttings'hyponastic rooting. The rooting effectiveness of cutting was different among the different cutting parts and the numbers of keeping leaves. The middle part cutting with three pieces of leaves from one-year-old branch had the highest rooting rate in April, up to 77.04%.2) Based on the location of adventitious roots emergence of cuttings of A. sinensis, the adventitious roots of the species was mostly originated from both cortex and callus of the cutting'bottom section, and also from cortex or callus of cutting's bottom section alone. On the basis of rooting process, the adventitious roots formation of semi-lignified of A. sinensis can be divided into 4 stages after cutting : 1) 0～20 days, the callus induction and genesis period; 2) 20～30 days, the adventitious roots induction and genesis period; 3) 30～40 days,the adventitious roots formation and elongation period;4) after 40 days,the adventitious roots emergence and development period. 3) The rooting rate was positively correlated with the contents of IAA,ZR,GA and IAA/ABA, but negatively with the content of ABA. The treatment with plant growth regulator of IBA1500 mg·L-1 or ABT1#1000 mg·L-1 could boost the content of IAA , GA and decrease the content of ABA of the cutting. Both treatments were all beneficial to the formation of adventitious roots, but IBA1500 mg·L-1 treatment was better than that of ABT1#1000 mg·L-1 treatment in the rooting effectiveness of cuttings. During the rooting period, endogenesis hormones such as IAA,ABA and ZR correspondly regulated the formation of adventitious root. The dynamic banlance between contents of IAA and ABA was specially critical.4) The contents of soluble protein, soluble sugar and starch in cuttings were positively correlated with the rooting rate. During the adventitious roots induction and the adventitious roots formation period, the contents of soluble protein, soluble sugar and starch in cuttings could be kept at a higher level. The contents of soluble sugar and starch of cuttings with keeping three pieces of leaves are higher than that with keeping two pieces of leaves. The cuttings of middle part with three pieces of leaves were more conducive to adventitious roots induction and formation than the other three treatments.5) The rooting rate was positively correlated with the activity of POD and PPO, but negatively with IAAO in cuttings. During the critical period of callus formation and adventitious roots induction, the activity PPO and POD of cuttings could be kept at a higher level. During the period of adventitious roots formation and development, the activity of PPO and POD of cuttings were reduced, but IAAO activity was increased. After the adventitious roots emergence, the three oxidation enzymes activity decreased. IBA 1500 mg·L-1 treatment could boost the activity of POD and PPO, decrease the activity of IAAO of cuttings, which were beneficial to adventitious roots induction of cutting.6) There existed some materials influencing and inhibiting rooting of cuttings of A. sinensis. The contents of these inhibitor materials were different in the different parts of branches of A. sinensis, relatively higher in the basal part cutting. |
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