Rapad Micro-propagation And In Vitro Flowering Influence Of Cymbidium Goeringii

Cymbidium goeringii(Rchb.f.)has a long history cultured in China and the other countries of South-East Asia.Because of its various petaline type and elegant flower color,it gains the favor of the public and is wide spread cultivated.But to create a hybrid will take at least 10 years through pollination,fruitage,flower and selection,which turns out to be a higher cost than other herb flowers.There are some urgent problems need to be solved,which are how to shorten the rearing period,get fine properties of flower types in advance,and lower the cost.Tissue culture as a technology is an effective technology to solve the above questions.So the rhizomes and tube plantlets from seeds of Cym.goeringii hybrid F1 were used as materials to study the regeneration system,in vitro flowering,and the correlation between endogenous hormones.The main aim of this study was to shorten the transition from vegetative to reproductive growth,overcome the confines of seasonal growth rhythm on blooming,and explore the differentiation regulation of the flower bud induction,as well.The main results are as follows:1.In the plantlet regeneration stage,the optimal proliferation medium is 3.0 g·L-1 Hyponex Ⅱ+0.5 mg·L-1 6-BA+3.0 mg·L-1 NAA+1.0 g·L-1 peptone+1.0 g·L-1 Activated Carbon(AC)+ 30.0 g·L-1 Sugar(Su)+7.0 g·L-1 Agar(Ag),with the growth rate and multiplication coefficient as 7.31 and 6.02,respectively.The optimal differentiation medium is 2.0 mg·L-1 6-BA+ 0.3 mg·L-1 NAA+30.0 g·L-1 Su+ 7.0 g·L-1 Ag,with the differentiation rate,bud induction number,and plant height as 90%,5.44 buds per rhizome segment,and 2.53 cm per plantlet,respectively.The optimal culture medium for rooting is 1.5 mg·L-1 IBA+2.0 g·L-1 peptone+50.0 g·L-1 banana+60.0 g·L-1 potato+1.0 g·L-1 AC+ 25.0 g·L-1 Su+7.0 g·L-1 Ag,with the rooting rate,average root number,and average root length as 100%,8.03 strips,and 3.00 cm,respectively.After 60 days of acclimatization,the survival rate can be up to 96.53%.2.In the in vitro flowering stage of Cym.goeringii rhizomes,the cytokinin,6-BA and TDZ,is the main factor for flower bud induction,with 6-BA(8.0 mg·L-1)more suitable than TDZ and high frequency of floral bud induction but low normal flower bud rate as the effects of TDZ.Low levels of NAA are more suitable for the blooming of flower buds with the optimal concentration at 0.1 mg·L-1.Comparing to the normal content of phosphorus in MS,two to three times of phosphorus could significantly increases the frequency of floral bud induction.The most suitable sugar concentration for flower bud induction is 35.0 g·L-1,more than which will have the inhibition effect.The optimal culture medium for in vitro flowering of C.goeringii plantlets is 1.5 mg·L-1 IBA+3.0 g·L-1 peptone+50.0 g·L-1 banana+60.0 g·L-1 potato+ 1.0 g·L-1 AC+25.0 g·L-1 Su+ 7.0 g·L-1 Ag,with the flower bud induction rate at 20.00%and without immoral flower bud as the result.3.Range of temperature and photoperiod have little impact on in vitro flowering of Cym.goeringii rhizomes,indicating that they are not the decisive factor.For flower bud differentiation of rhizomes,the suitable light intensity is 700～800 lx with the flower bud induction rate and normal flower bud induction rate at 19.08%and 10.24%,respectively.The most suitable in vitro flowering culture is 100 μmol·m-2·s-1 light intensity+1R:1B:0.01G lightist+ 14/10 h·d-1 day/night,with the flower bud germination rate,normal flower bud germination rate,and leafbud germination rate at 23.43%,11.88%,and 50.35%,respectively.It would inhibit flower bud differentiation as the red light increased and the LED lighting system has higher flower bud germination rate and normal flower bud rate than those of fluorescent tubes.4.At the beginning of the flower bud differentiation from rhizomes,low levels of ABA,GA3,and high levels of 1AA,ZR is more beneficial.Four endogenous hormones reached the peak at full-bloom stage.It is conducive for flower bud formation as ZR/IAA and ABA/IAA decreased and ZR/GA3,ABA/GA3 increases.High levels of ZR/IAA,ABA/IAA,and ZR/GA3,and low level of ABA/GA3 are beneficial to the flower bud growth.As the exogenous hormone NAA increasing,ABA and ABA/GA3 in rhizome at the full-bloom stage decreased,while IAA,GA3,and ZR rised as well,which is not suitable for the flower blooming.As the exogenous hormone 6-BA increasing IAA and GA3 in rhizome at the full-bloom stage decreased,while ABA/IAA,ZR/GA3,and ABA/GA3 rised as well,which is suitable for the flower blooming.