| Cremastra appendiculata seeds from artificial pollination were used as test materials to screen the suitable medium for seeds germination.The test contents involved the effects of the basic medium,organic additives,sucrose concentration,growth regulators,environmental conditions,and mycorrhiza fungi to seeds germination of C.appendiculata.Meanwhile,the method of morphogenesis observation and structural anatomy were used to learn about the dynamic change of embryo in the process of seed germination of C.Appendiculata.Preliminary clarify its germination barriers and established methods of seed germination.The main results and conclusions are as follows:?1?C.appendiculata seeds germination process can be divided into mature stage,dormancy stage,expansion and breakthrough stage and protocorm development stage.The structure of mature seeds which only have an endotesta,a testa and a original embryoid body without endosperm are simple.The side and radial wall of testa are thickened due to lignified,and seeds will rest on the dormancy stage for a long time in vitro because of the existence of dense membranous endotesta.Therefore,incomplete embryo structure?no endosperm?and seed coat inhibition are the main obstacle of C.appendiculata seeds germination difficulty.By comparing the seed and embryo traits at the different storage time,preliminary confirmed the after-ripening existed in C.appendiculata seeds.?2?Seeds treated by 2% NaOH for 15 min could effectively improve seeds germination rate,at 16.76%;and seed scarification could shorten germination time but at the same time could damage the embryo to lower germination rate.And seeds stored at low temperature had higher germination rate?11.13%?,and its germination time was about 15 weeks.It showed that the appropriate pretreatment could break the inhibition of seed coat to germination.The single factor experiment results showed that seeds which was in KC basic medium had higher germinationrate?17.38%?.Adding 7.5% mashed potatoes into KC medium was beneficial to seeds germination,and the germination rate was 15.36% The seeds germination rate was higher?14.20%?when sucrose concentration was 1.0%.0.5 mg·L-1 KT or 1.5 mg·L-1 IBA was the suitable growth regulators,seeds germination and the germination rate was 36.19% and 30.00%,respectively.In conclusion,the best medium for seeds germination of C.appendiculata was KC +0.5 mg·L-1 KT + 1.3 mg·L-1 IBA + 1.0% sucrose + 7.5% mashed potatoes + 0.5 g·L-1 AC,which seeds germination rate was 32.87% and germination time was 6 weeks.The results showed that suitable medium could replace the internal nutrition?endosperm?for seeds germination.Within certain limits,the effects of environment conditions on seeds germination were not obvious,but when the condition is 100 lx,25 ? and pH 5.5 respectively,germination rates attained the maximum.14 fungi which were isolated from the roots of C.appendiculata were used to symbiose with seeds.However,The symbiotic germination experiment had no results and was failure.It could be due to a strong specificity between C.appendiculata and fungi,as well as the medium which was used for symbiotic germination was not suitable for seeds expanding to protocorm and forming rihizoid to fungi infection.The NO.1 strain was identified primarily to Paecilomyces sp.,the NO.2 and NO.4 was identified primarily to Metarrhizium sp.,NO.7 was identified primarily to Hymenella sp.,NO.9 was identified primarily to Starkeyomyces sp.,NO.10 was identified primarily to Cephalosporium sp.,and others were not identified accurately because of the conidiums and conidiogenous structure could not be observed by repeatedly making slide sample,and maybe provisionally regarded as Rhizoctonia sp.. |
PDF Full Text Request