Morphological,Physiological And Biochemical Studies On Seed Development Of Panax Quinquefolium

Panacis quinquefolii radix is a well-known chinese medicine with remarkable effect on nutritious Yin and clearing heat, because of good social and economic benefit, the market demand is more and more big. Panax quinquefolium is the original plant relied on seminal propagation, however its development rate was low and process-time was very long on account of morphological and physiological after-ripening trait. This paper studied seed growth and development of Panax quinquefolium through3aspects from morphology, physiology and molecular biology. The main results are as follows:1. The flowering habit were obtained by field observation, and morphological characteristics of seed and embryo development were observed under the microscope by making paraffin section. We find that the plant got to the most flowering numbers in5-8d after initial blooming time, has campylotropous ovule and triporate pollen grains. The seed was wide obovate when matured, the morphological development of embryo was stopped at torpedo form of embryos after a series of forms.2. To investigated the size, fresh and dry weight changes of developmental fruit and seed, we sampling periodically. Size and weight were all reached maximum in fruit maturation period. We also determined changes of seed endogenous hormones content using ELISA. The results showed that IAA and ABA content were both in high level and the variation trend were obvious, then GA content was slightly downgrade. ABA content changes had a same trend with ZR but an opposite with IAA. The changes of hormone ratio indicated that28-48d may be the most important developmental stage of seed for the balance of hormones interact with each other.3. In order to understand the transcriptome of Panax quinquefolium seed, a platform of Illumina HiseqTM2000based on the next generation sequencing technology was used in this paper. We took seed at different developmental stages as samples, finally25,865,496high quaility reads generated which were assembled into78,207Unigenes, there were54,292Unigenes annotated to several large databases such as NR, NT, COG, Swissprot, KEGG and GO. According to these annotations, we can easily know protein functions of gene product of seed, pirme metabolites pathways and function classifications. The data we got was served as reference sequence of DGE analysis.4. Embryo of0,45and90d after stratification seed in physiological after-ripening period has been chosen for RNA-Seq and DGE research. The sequencing results of3different stages were compared with each other, acquired differently expressed gene numbers0d/45d (6672),45d/90d (3870),0d/90d (12281) respectively. According to the terms under the GO biological process classification,131differently expressed Unigenes involved in hormones(ABA、GA and Eth) metabolism and signaling responses, or functions related to seed development and germination were screened. These genes should be regarded as key regulators of physiological after-ripening of Panax quinquefolium seed.