INDUCTION OF SOMATIC EMBRYOS AND REGENERATION OF PLANTLETS FROM RICE ROOTS

<正> The number of somatic embryos and regenerated plantlets were directly induced from irra-diated rice roots of the variety Taipei 309(Oryza sativa L.).For the induction of somatic em-bryos,the suitable age of roots was no more than 7 days after seed culture on the medium and thesections near tip were more vigorous than those near base of a root;the number of somatic em-bryos induced by the media with 1.11mg/L2,4-D plus 0.47mg/L NAA and 2.21mg/L 2,4-Dplus 1.86mg/L NAA was much higher than that induced by 1.11mg/L 2,4-D alone;10～20 Gyand 40 Gy of γ irradiation were the most favourable for increasing somatic embryo number onthe media of 2.21mg/L 2,4-D plus 1.86mg/L NAA and 1.11mg/L 2,4-D plus 0.47mg/L NAAor 1.11mg/L 2,4-D alone respectively.The highest number of regenerated plantlets was fromthat cultured on the medium of 1.11mg/L 2,4-D plus 0.47mg/L NAA and irradiated with 30～40 Gy of γ rays.     

Current Research and Development on Deformation and Fixation of Bended Wood and Wood-based Composites

There are many advantages of bended wood,such as good-looking shape,simple process and low cost.The product,however,is easy to get recovery,which is urgent to be dealt with.This paper concludes the features of deformation and recovery of bended wood and wood-based composites and summarizes four treating methods to keep dimensional stability.Compared to bended solid wood,some elementary perspectives on the research of bended wood-based composites are presented.The purpose of this paper is to suggest:1)to investigate the optimum heating time and temperature that bended wood and wood-based composites need from the formation of deformation to the recovery and to the permanent fixation,according to its changes of dimensional stability such as curvature radius;2)to measure the composites comprised of wood and adhesives on the changes of stress relaxation,dynamic viscoelasticity and crystal1ization field;3)to quantitatively analyze changes of the major components in wood cell wall polymers as well as the composites under heat/steam treatment and untreated conditions.It will be helpful for subsequent research to clarify on the mechanisms of permanent fixation of bended wood and also contribute to that of wood-based composites.     

抗稻瘿蚊品种多抗1的抗性遗传分析及抗性基因定位

稻瘿蚊是亚洲稻区主要害虫,采用抗虫品种进行防治是最理想的方法。1993～1995年,广东省农科院与国际水稻研究所有关专家紧密合作,对能抗华南4个稻瘿蚊生物型的品种多抗1作进一步抗性遗传分析,确认多抗1对中国稻瘿蚊生物型1和4的抗性受显性单基因控制,这个基因暂定名为GM—6(t)。以多抗1×丰银占1组合的F3代160个家系作基因标记,据DNA库分离个体分析(BSA)原理,用随机扩增多态性DNA(RAPD)标记物OPM6(1.4kb),首次成功地标记了这个抗性基因。随后多态性扩增产物经~(32)p标记,用作探针,检测另一个参考作图群体IR64×Azucena,将这个抗性基因定位在水稻第4条染色体上,位于RG214和RG163两个DNA限制性片段长度多态性(RFLP)标记之间。应用这些分子标记辅助选择有可能不必通过稻瘿蚊的直接筛选,快速准确地选育抗稻瘿蚊品种或进行抗性基因累加。     

甜椒栽培实用技术指南

为实现甜椒丰产、优质、高效、安全的生产目标,促进世界辣椒产业发展,本文从甜椒对气候与土壤的要求,到栽培中品种选择、种子处理、育苗、移栽、施肥、田间准备和采收,提出了甜椒栽培技术指南。并列举了常见甜椒生产中的主要病虫害,提出了综合性防治措施。     

禽的冷冻颗粒精子的超微结构的破坏

在禽精子的冷冻和融化期间观察其超微结构的变化,用以研究精子被破坏的有关因素。用各种稀释液稀释的精液用颗粒法冷冻或在5℃贮存24小时。这些样品用于电子显微镜扫描(SEM)和透射电子显微镜(TEM)里的单阶段碳复制。1.当用 SEM 对冷冻-融化精子进行扫描时,约10%的精子是弯曲的,7%表现出顶体变形。“弯曲”精子的头在颈部和整个中段越折。最严重的顶体畸形是从核前端完全脱离。然而,有时只见精子头的后端发生肿胀而没有     

一种适宜从小麦种子上分离细菌性黑颖病原菌的半选择性琼脂培养基

一种半选择性琼脂培养基(XTS 琼脂)被研制出。经试验,它适宜从小麦种子上分离细菌性黑颖病原菌 Xanthomonas campe-stris PV.translucens。这种培养基的成分如下:Difco 营养琼脂 23g葡萄糖 5g放线菌酮 200mg     

水稻灭茬机扶茬机构设计与试验

【目的】解决水稻灭茬机作业时,驱动轮容易将高留茬压倒,引起轮辙处倒茬多,导致水稻秸秆粉碎效果不理想的问题。【方法】研发了一种具有扶禾功能的水稻灭茬机,利用固接于扶茬轮轴上的"L"型扶指,采用扶茬轮轴和粉碎轮轴双侧带轮分流传动方式,实现前置扶茬系统与后置粉碎系统配合作业,使水稻秸秆倒伏的留茬被扶起后立即喂入粉碎室。采用正交设计试验验证灭茬机的田间性能。【结果】水稻灭茬机的前进速度、扶辊转速和扶指宽度均对水稻秸秆粉碎率有显著影响。田间试验的结果表明,机具工作参数的最佳组合为前进速度5.38 km·h~(–1)、扶辊转速160 r·min~(–1)和扶指宽度50 mm,该组合的水稻秸秆粉碎效果最好,粉碎率达到92.52%。【结论】该扶茬机结构简单,对水稻秸秆的扶茬粉碎效果好,在实际生产中能够提升高留茬稻秆的粉碎效率。     

Improving Drought Tolerance of Rice by Designed QTL Pyramiding

Drought is the most important factor limiting rice yields in the rainfed areas of Asia. To overcome the problem, we developed a new strategy ＇designed QTL pyramiding＇ to more efficiently develop drought tolerant （DT） rice cultivars. In the first phase of this strategy, we developed large numbers of introgression lines （ILs） in elite backgrounds using backcross （BC） breeding, each of which carries multiple genomic segments for improved DT from a known donor. Then, we genotyped all ILs with SSR markers to track the genomewide pattern of introgression in the DT ILs of 16 BC populations derived from crosses between 2 recipients （IR64 and Teqing） and four different donors. X^2 tests and linkage disequilibrium analyses of introgression in the DT ILs revealed significant frequency shifts at many loci across the genome and non-random associations at the multilocus level as a result of selection for DT in the ILs, which led us to the discovery of putative genetic networks underlying DT in the ILs. The networks each containing all DT loci detected in ILs from a BC population showed some interesting features.     

秋水仙素对小麦小孢子胚胎发生产生双单倍体植株的直接影响

研究了不同的染色体加倍技术对来源于小麦(Triticum aestivum L.)(品种为Ciano)小孢子的单倍体加倍的效果。除了常规的处理(将整个植株浸于秋水仙素溶液)方法外,还检测了自发加倍的单倍体。将不同浓度(0.01%,0.02%,0.04%)的秋水仙素直接加入诱导培养基作为实验处理。秋水仙素不影响花药反应或植株再生能力。根据再生植株(R_0)及其后代(R_1)的育性评价了染色体组加倍的效果及其稳定性。在小孢子第1次有丝分裂之前用秋水仙素进行染色体加倍比常规加倍技术明显有效。