Researches On Tissue Culture And Cutting Propagatiuon Of Photinia Serrulata And Photinia×Fraseria

Photinia serrulata and Photinia×fraseria are valuable ornamental tree species, leaves of Photinia serrulata are commonly used as Chinese medicinal materials as well. This paper exploited the efficient technique systems of rapid propagation of these two species from tissue culture and cutting.Using terminal buds,axillary buds,leaves, petioles,cotyledos and hypocotyls as explants for experiments,in vitro regeneration system of tissue culture from direct organogenesis and indirect organogenesis was established.Cutting experiments with new shoots as cutting branches were conducted in spring and autumn to check the effect of rooting reagents and their concentration on rooting of these two plants。Major results are as following:(1) NaClO was selected as the surface disinfectant.It was suitable to disinfect leaves with 0.5%NaClO for 25 min,to disinfect petiole with 1%NaClO for 30min and to treat stem with 2%NaClO for 20min.(2) In the terminal bud and axillary bud initiating period,the germination rate of Photinia serrulata is slightly higher than that of Photinia×fraseria.The optimum initiation medium for terminal bud and axillary bud was MS and MS+0.5mg/L BA respectively.(3)Both BA and NAA had important influences on differentiation of adventitious buds from aseptic petioles.The optimum medium for adventitious buds induction of Photinia serrulata was MS+1.5mg/L BA+0.2mg/L NAA.For Photinia×fraseria,both the induction rate and number of adventitious bud reached the highest when cultured in the medium of MS+2.0mg/L BA+0.2mg/L NAA.(4) TDZ was able to increase the number of adventitious bud from petioles of Photinia serrulata.In the medium of MS+3.0mg/L TDZ+0.1mg/L NAA,the average adventitious bud number per explant is 5.2.(5) Adventitious bud could be differentiated at the cutting edges of leaves of Photinia serrulata and Photinia×fraseria.When leaf explants were cultured in dark for the first 12d,the induction rate and number of adventitious buds were obviously improved.The effect of BA on the result is also significant.When BA concentration increased to 2.0mg/L and 3.0mg/L,the adventitious bud induction rate was getting higher.(6) Compared with cotyledon,direct initiation of adventitious buds from hypocotyl was better.When cultured in the medium of MS+2.0mg/L BA+0.1mg/L NAA,the induction rate of adventitious bud is 69.2%,average adventitious bud number per explant is 1.9. (7) In the process of callus induction,to using aseptic leaves as explants showed some advantages such as convenient to get cxplants,easy to operate and high callus inducation rate.When cultured in tbe medium of MS+0.5mg/L BA+1.0mg/L 2,4-D in dark for the first 8～12d,then in light,callus inducation rate of the aseptic leaf cxplants of Photinia serrulata and Photinia×fraseria reached 98%or more after 30d culture.The optimum medium for callus subculture is MS+3.0mg/L BA+0.2mg/L NAA.At the stage of adventitious bud differentiating from callus,Photinia serrulata needs more BA and NAA,and MS+3.0mg/L BA+0.2mg/L NAA and MS+2.0mg/L BA+0.1mg/L NAA should be selected for the two plants respectively.(8) In the process of muitiplication,the optimum medium for Photinia serrulata was MS+2.0mg/L BA+0.1mg/L NAA,that for Photinia×fraseria was MS+0.5mg/L BA+0.1mg/L NAA.Compared with KT,GA₃ has obvious better effect on shoots growth.(9) Under same condition of hormone,the rooting rate of Photinia×fraseria is significantly higher than that of Photinia serrulata.Dark culture for 8d first promoted root differentiation.In medium of 1/2MS+0.5mg/L IBA+0.5mg/L NAA+20g/L suger, rooting rate reached the highest,which was 72.3%for Photinia×fraseria and 91.7%for Photinia serrulata.(10)When transplanting,the mixture with 2 parts of undergrowth soil and 1 part of perlite was used as medium,and the survival rote of Photinia serrulata and Photinia×fraseria reached 77.7%and 94.7%respectively.(11) Rooting of the cuttings of Photinia serrulata and Photinia×fraseria was quite slow.Therefore the propagation cycle was long.Rooting reagent can accelerate rooting process and root growth in some extent.Rooting rote and root number can be improved by treating the cuttings for about 5s with 400mg/L IBA or NAA.The highest rooting rote of Photinia serrulata and Photinia×fraseria reached 80%and 86.7%in respective.