Embryogenesis and Development of Isolated Microspore in Chinese Cabbage

[Objective] The aim was to observe embryogenesis and development of isolated microspores in Chinese cabbage. [Method] Chinese cabbage F 1 hybrids were used as the experimental materials, and optical microspore was employed to observe the embryogenesis and development of isolated microspores. [Result] Cells swelled after heat shock treatment, which was the critical factor of embryoid induction. Three pathways equal division, unequal division and germination of microspores were discovered to lead to the embryogenesis from isolated microspores after swelling. Microspore could grow directly to embryoid through germination path way. Equally divided microspores formed the original embryos after successive multiple equal divisions. Original embryos could develop into cotyledon-shaped embryos via globular, heart-shaped and torpedo-shaped embryos. The large one of the two cells from unequally divided microspores continued to divide and finally formed a polar embryoid. [Conclusion] The study will provide cytological basis for high induction frequency and embryoid of Chinese cabbage.

Establishment on Isolated Microspore Culture Optimized System for Restorer of New Cytoplasmic Male Sterile (NER) of Brassica napus L.

[Objective]The aim was to establish optimized system for NER isolated microspore culture of Brassica napus L.. [Method]Twenty varieties of NER of Brassica napus were grown under uncontrolled temperature and light conditions,and their isolated microspore from anthers were used as explants in vitro culture. The influencing factors of microspore culture were preliminarily studied. [Result]The difference of genotypes was important influencing factors to embryoid yield. The embryoid yield increased by supplementing with 6-BA and NAA,culturing in solid-liquid double layer medium with activated charcoal; The difference was not significant of embryoid yield between culturing in medium supplemented with colchicines and the CK. The rates of cotyledonous embryoids directly developed into normal plantlets increased through enriching with 0.1-0.2 mg/L NAA and being treated on slim illumination two days before being inducted into normal plantlets. [Conclusion]The technical system of microspore culture of restorer of new cytoplasmic male sterile （NER） was established,which and lays a foundation for accelerating genotype purification of NER introgressive line.

Isolated Microspore Culture and Plant Regeneration of Leaf Mustard(Brassica juncea(L.)Czern.et Coss.)

Isolated micmspore culture was carried out with Brassica juncea to study the effects of sterilization methods, culture period of embryos, hormone formula and the concentration of aetivatod carbon on embryogenesis, and the concentration of NAA on induction of roots. The results showed that the embryogenesis on medi- um subjected to filter sterilization is better than medium subjected to autoclaved sterilization. The embryos cultured for 15 d had the highest plantlat regenexafion rate （52%）. NLN-13 liquid medium including 0. 1mg/L 6-BA and 0.2 g/L activated carbon significantly improved the planflet regeneration rate. 1/2 MS inclu- ding 0.3 mg/L NAA had the highest plantlet regeneration rate （ 100% ）. Key words Brassica juncea ; Isolated micmspore culture ; Embryogenesis ; Planflet regeneration

Studies on Enhancing Yield of Embryos in Microspore Culture of Brassica napus L.

In ecological zone of Chengdu, Sichuan, microspore culture was carried out in Brassica napus L. to study the influencing factors on microspore culture. The results showed that the temperature on microspore formation stage, day and night temperature, disinfection solution of buds, cultivation concentration on microspore and strain-age were both important influencing factors on microspore culture. At a temperature below 5 ℃ or above 20 ℃, the material had a much lower embryo producing rate or even could not produce any embryo, but at the optimum temperature of 10 -15 ℃ the embryo yield was up to 300 pieces per bud; the best cultivation effect appeared when 0. 1% HgCl2 was used for disin- fection; the best density of microspore was 3 -4 buds per dish; In 2009, while strain-age was from 125 d to 150 d, the microspore embryo yield increased as strain-age increased. When stain-age was 150 days, the microspore embryo yield was up to the highest, but the yield declined after 150 days.