山区农民草鱼小塘快养技术

山区农民不少仍吃鱼难。我县属山区,近些年推广小塘活水草鱼快养术,不仅解决了山区农民吃鱼难的问题,还有效地解决了生产、生活用水之难,同时又增加了他们的收入。通常情况0.2—0.25公斤的鱼苗经5—6个月小塘活水精养,每尾可达1.5—3公斤。一口30平方米活水精养小塘、所产鲜鱼,可供5口之家四季所需,并有余出售。现将关键技术简介如下:

山区草鱼小塘快养技术

1、选址挖塘 最好选房前屋后土体深厚的粘质地块挖成小塘。若土质不好有轻微渗漏,可在塘底及四周铺埋无缝厚农膜。塘大小不限,一般面积20～200平方米,深70～100厘米。塘堤四周筑实。

Embryo culture and rapid propagation of Syringa

Embryo of lilacs (Syringa L) culture in vitro and the rapid propagation were studied. The orthogonal experiments, in-cluding the selection of basal medium, embryo age and other factors such as sugar, benzyladenine (BA), naphthalene acetic acid (NAA) and glutamine (Gln), were carried out. The results indicated that the optimal medium for embryo culture was Monnier medium supplemented with NAA (0.001 mgL-1), BA (0.1 mgL-1), sugar (50 gL-1), and Gln (400 mgL-1), with a germination rate of 91.7% at least; the optimal embryo age was 50 d; and Gln had significant effects on the germination rate of embryo. Moreover, the optimal medium for subculture was MS+BA (2 mgL-1)+NAA (0.001 mgL-1)+Gln (0.5 mgL-1), with the propaga-tion coefficient of 3.6 at least.

Tissue Culture and Rapid Multiplication Techniques of Apocynum L.

[Objective] This study aimed to investigate rapid multiplication of Apocynum by tissue culture so as to provide plantlet sources for its industrialized cultivation. [Method] The asepsis seedlings were obtained by dealing with Apocynum seeds. Its cotyledons, hypocotyls and shoot tips were cultured on the media containing different concentrations of hormones. Finally, the influence of different hormone combinations on differentiation of cotyledons and hypocotyls, rapid multiplication of shoot tips, rapid multiplication of regenerated shoots, and rooting of test-tube plantlets was com- pared. [Result] MS＋2.0 mg/L BA＋0.03 mg/L NAA and MS＋0.07 mg/L NAA were the optimum medium for inducing regenerated buds from cotyledons and hypocotyls re- spectively; MS＋2.0 mg/L BA＋0.02 mg/L NAA was the best medium for rapid multi- plication of shoot tips; MS＋1.9 mg/L BA＋I.7 mg/L NAA was the best medium for rapid multiplication of regenerated buds： and 1/2MS＋0.6 mg/L NAA was the best medium for inducing roots. [Conclusion] The optimum hormone combination was de- termined for Apocynum rapid multiplication by tissue culture, which provides technical support on Apocynum industrialized cultivation.

Tissue culture of three species of Laurencia complex

To establish a micropropagation system of three Laurencia complex species （Laurencia okamurai, Laurencia tristicha, and Chondrophvcus undulatus） by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with 0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20℃ and 35 （salinity）; for C. undulatus, 4 500 lx, 20℃ and 30; and for L. tristicha, 4 500 lx, 25℃ and 30.

Research on Rapid Propagation of Gongshui Pomelo by Tissue Culture

[Objective] This study aimed to investigate the optimal medium and hor-mone combinations for efficient rapid propagation of Gongshui pomelo and analyze key technical measures in the tissue culture process. [Method] Stem tips and stem segments with buds were col ected from four varieties of pomelo adult trees as explants, to investigate the main effect and key regulatory factors of vegetative organs and tissue culture explants and to propose a series of measures to prevent and control microbial contamination. Final y, an efficient rapid propagation technology system of Gongshui pomelo was established. [Result] Spring shoot explants contained large amounts of auxin, cytokinins, gibberel ins and other growth regulators, which could be used for tissue culture with high bud generation rate and rapid growth. Different conditions led to various culture results. Specifical y, mature pomelo seeds should be generated on semisolid 1/2MS medium and transferred to solid MS medium for incubation. The propagation coefficient of stem segments with axillary buds was greater than that of stem tips, exhibiting significant differences. In ad-dition, the optimal hormone combination was 6-BA 0.5 mg/L ＋ NAA 0.5 mg/L, which significantly promoted the induction and differentiation of adventitious buds. [Conclusion] This study provided basis for basic research, production and application of pomelo germplasm resources.

Micropropagation of Three Bamboo Species from Nodal Explants of Mature Culms

A micropropagation technique is developed for the multiplication of Dendrocalamus strictus （D. strictus）, Dendrocalamus asper （19. asper） and Bambusa bambos （B. bambos） through shoot proliferation. Nodal explants obtained from field gown clumps were used to initiate cultures. Shoots were induced on Murashige and Skoog＇s （MS） medium supplemented with 5 mg L^-1 6-benzylamino purine （BAP）. Rapid shoot multiplication was obtained on MS medium containing 3 mg Lt BAP in D. asper, B. bambos and 2 mg L^-1 BAP in D. strictus. In vitro multiplied shoots showed best root induction on half strength MS supplemented with 1 mg L^-1 indole-3 butyric acid （IBA） and 0.5 mg L^-1 1-naphthalene acetic acid （NAA） in D. asper. Pre-rooting conditioning followed by culturing on half strength MS supplemented with 1 mg L^-1 IBA and 2 mg L^-1 IBA showed maximum root induction in D. strictus and B. bambos, respectively. Further root proliferation was obtained on hormone free medium. The micropropagated plantlets were acclimatized and successfully transferred on soil in green house.