Study On Tissue Culture And Browning Control On Explant Of Phalaenopsis

Adventitious buds were induced from peduncle buds and leaves of nine Phalaenopsisvarieties on the same media, so as to compare the differences of shoot induction rates andpropagation coefficients among varieties. On the basis of above results, three representativevarieties,‘Kaleidoscope’,‘Brother Dream “L”’ and ‘Neyshan Guniang’ were selected.Which had the maximum, medium and minimum propagation coefficient, respectively, tooptimize the adventitious bud propagation condition. Meanwhile, the effects of heat-shock,salicylic acid and heat-shock combined with salicylic acid treatments on explants browningwere studied with the highest browning degree variety ‘Neyshan Guniang’. The resultsshowed that:1. There were significant differences on adventitious bud induction rates among differentvarieties, and so were propagation/differentiation coefficients. In the experiment, it had beenobserved that high flower stalk bud induction rates and propagation coefficients wereaccompanied with high leaf in vitro shoot induction rates and differentiation coefficients. Themajor influence factor on in vitro shoot proliferation was6-benzylaminopurine （6-BA）,followed by coconut milk. The suitable medium for adventitious bud propagation of ‘NeyshanGuniang’ and ‘Brother Dream “L”’ was1/2MS+7.0mg L^-16-BA+0.2mg L^-1NAA+100mL·L^-1coconut milk, and the medium1/2MS+5.0mg L^-16-BA+0.2mg L^-1NAA+50mL·L^-1coconut milk was appropriate for the adventitious bud propagation of‘Kaleidoscope’. On the rooting medium1/2MS+0.5mg L^-1NAA+1g L^-1activatedcarbon, the rooting rate of nine varieties were all above90%.2. Explants browning could be significantly inhibited by heat-shock at40℃for9min.Browning index, total phenol content and PAL activity were significantly below against CKof leaves cultured after heat-shock treatments, and they had very significantly positivecorrelation. These proved that short time of heat-shock could reduce PAL activity and phenolcompounds accumulation, thus reduce brown injury in the process of culture.3. Phalaenopsis ‘Neyshan Guniang’ variety was cultured on medium with differentconcentration of salicylic acid （SA）, and selected the safe usage of SA concentration,which is0⁰.2mmol L^-1by observe blade situation. SA treatments(0.05,0.1and0.2mmol L^-1)treatment could decrease browning index，total phenol content and PAL activity, increase theSOD, POD and CAT activity. And0.1mmol L^-1SA treatment with the best effect of tissue browning reduce.4. Heat-shock treatment （40℃,9min） and salicylic acid （SA,0.1mM） used alone andheat-shock combined with salicylic acid treatment could inhibit leaf browning ofPhalaenopsis ‘Neyshan guniang’ variety, could reduce browning index total phenol contentand PAL activity, increase the SOD, POD，CAT activity and induction rate. And heat-shockcombined with salicylic acid treatment with the best effect of browning reduce.