DYNAMICS OF SOME BIOMACROMOLECULES DURING EMBRYOGENESIS IN RICE

The DNA and RNA content as well as cell number per embryo increased rapidly during the differentiation of rice embryo (6 to 13 days after anthesis), and tended then to become constant. But during the 18 to 25 days after anthesis, the quantity of RNA rose again. The protein content changed almost in correspondence with the dynamic variation of RNA content. The starch accumulation and utilization performed a regulatory function on embryogenesis. With the development and maturation of embryo the degradation of 18S rRNA in the embryos of frozen-stored seeds reduced regularly showing that the rRNAs (ribosomes) gradually accumulated and were protected in some ways during embryo ripening. In the light of discussion about the relationships between the dynamics of biomacromolecules and the progress of embryogenesis, it was suggested that the developmental progress of rice embryogeny was divided into four stages, namely, the proembryo-, differentiation-, maturation- and quiescence-stage.     

从三叶半夏(Pinellia ternata Breit)叶肉原生质体再生植株

从三叶半夏叶片分离到大量、具活力的叶肉原生质体,采用无机盐、激素、蔗糖浓度不同的液体和固体双层培养基培养。4—7天内原生质体出现第一次分裂,分裂频率为3—8％,3周后形成80—100个细胞的细胞团,转入液体培养基中振荡培养,1月后将形成1—2mm直径的愈伤组织再转入固体分化培养基中,愈伤组织先增殖、生长,3—4周后分化出绿芽和小苗,再1月后,由原生质体再生的半夏小植株已长至6—10cm高。半夏原生质体再生植株的发生途径有器官型和胚状体型两种方式。比较和讨论了悬浮培养、双层培养和组份浓度差液-固体双层培养对原生质体培养的效果。     

PLANT REGENERATED FROM MESOPHYLL PROTOPLASTS OF Pinellia ternata BREIT

Large numbers of viable mesophyll protoplasts are isolated from soil-grown plants of Pinellia ternata Breit of Araceae by liquid-solid double layer media with different concentrations of mineral salts, hormones and sugar. The first division of protoplasts takes place in 4—7 days of culture, with a division frequency of 3—8%. Cell clusters of 80—100 cells form in 3 weeks. They are transferred into a liquid medium to culture for a month on a shaker to form calli of 1—2 mm diameter which are transferred onto a solid differentiation agar medium. The calli first proliferate and grow, and differentiate into green buds and small seedlings in 3—4 weeks. The plantlets of Pinellia ternata regenerated from protoplasts grow to a length of 6—10 em in another month. It was found that the shoot-forming process in the calli was to proceed in two ways: one was the organogenesis way, and the other was the embryoid way. Comparisons were made between the effects obtained from the 3 different methods, i.e. component c     

稻胚形成期间一些生物大分子的动态

本文证明稻胚分化期间(开花后 6—13d)每胚的DNA、RNA含量和细胞数都迅速上升.此后都趋于稳定,但 18—25d RNA再次增加.蛋白质含量基本上随RNA而相应地变化.淀粉的积累和利用对胚的发育有调节作用.冷藏稻种胚内18SrRNA降解程度随发育进程有规律地减小,表明rRNA(核糖体)在胚成熟期间逐渐积累并得到某些形式的保护.在讨论生物大分子动态与胚胎发育进程相互关系的基础上,将稻胚发育过程划分为原胚期、分化期、成熟期和休止期。