Somatic hybridization between male sterile Nicotiana tabacum and N. glutinosa through protoplast fusion

Summary Protoplasts derived from suspension cultured cells of cytoplasmic male sterile Nicotiana tabacum (N. debneyi cytoplasm) and of fertile N. glutinosa were fused with the aid of polyethylene glycol (PEG). Out of 1,089 colonies developed from PEG-treated protoplasts, 29 restored whole plants.A somatic hybrid plant was selected on the basis of isoelectrofocusing analysis of Fraction I protein in leaves of regenerated plants. A newly created hybrid contained small subunits of both parents but only a N. glutinosa type large subunit.Male sterile character was conserved in a hybrid plant while leaf morphology was intermediate between the parents. By tobacco mosaic virus infection tests, the hybrid's leaves showed resistant symptoms, hypersensitive local lesions, which were due to N. glutinosa nuclear genome expression.Abbreviations PEG Polyethylene glycol - TMV Tobacco mosaic virus     

A method for subgrouping the S-type of CMS forms in maize

Summary Simple correlations were calculated between nine different cms sources (cms-S, -R, -ML, -L, -CA, -EK, -C, -Rb, -T) on the basis of the weighted restoring reactions of 41 inbred lines. The Principal Component Analysis was applied to a 9 × 9 matrix which clearly grouped cytoplasms according to their similarities. The Principal Component I included S, R, ML, L, CA and EK cytoplasms; the Principal Component II contained C and Rb cytoplasms while T-cytoplasms was placed in Principal Component III. This corresponds to the main groupings indicated in the literature (Beckett 1971). However, after varimax rotation of the Principal Components, the S main group, including the 6 tested cytoplasms, fell into 3 subgroups: I.: S, R, ML; II.: L, CA; III.: EK.These data indicate that the Principal Component Analysis can be used to select a limited number of cms sources from the S group, representing the variability of the cytoplasmic gene pool of that group.     

Differences between genetic and physical centromere distances in the case of two genes for male sterility in barley

Summary Linkage studies with thirty translocations (one of the two chromosomes involved being number 4) in relation to msg24 (chromosome 4) and thirteen translocations (one of the two chromosomes involved being number 6) in relation to msg6 (chromosome 6) show without exception close linkage for all combinations tested. The results indicate that both genes are located genetically in or close to the centromere regions of their chromosomes.Cytological analysis of two BTT stocks (balanced tertiary trisomics) ascertained the respective chromosome arms (both msg24 and msg6 on the short arms) and revealed marked differences between genetic and physical centromere distances. The reason is obviously the high content of centromeric heterochromatin occupying both the chromosome arms involved.     

Amino acids in anthers of Milo and in cytoplasmic genetic male sterile sorghums (Sorghum bicolor L. Moench) of Indian origin

Summary Amino acid composition of proteins from anthers of milo and Indian origin male steriles were determined. Comparison of amino acid between A and B lines showed lower contents of histidine, threonine, glutamic acid, glycine, leucine and phenylalanine and higher contents of alanine, serine, proline and tyrosine in line A compared to line B. Alanine content in anthers of A lines was more than two fold higher than that in the anthers from B lines. Marked differences in amino acid composition of anthers of A and B lines are suggestive of their involvement in male sterility. Cytoplasmic male steriles of Indian origin M35-1A and M31-2A showed greater similarity but differed from milo, VZM2A and B.     

Mitochondrial gene expression and cytoplasmic male sterility in sorghum

Variation in sorghum mitochondrial translation products has enabled fertile (Kafir) cytoplasm to be distinguished from Milo cytoplasmic male sterile cytoplasm and from three alternative sources of cytoplasmic male sterile cytoplasm. Mitochondria from Milo cytoplasm synthesised a 65 000 mol. wt. polypeptide which was not synthesised by those from Kafir cytoplasm. In the cytoplasmic male sterile combination of Kafir nucleus in Milo cytoplasm synthesis of this polypeptide was dramatically increased. Mitochondria from two cytoplasmic male sterile lines (Kafir nucleus in IS1112 cytoplasm and Yellow Feterita nucleus in M35-1 cytoplasm) did not synthesise the 65 000 mol. wt. polypeptide but synthesised additional high molecular weight polypeptides (from 54 000 to 82 000 mol. wt.), the major one being 82 000. Mitochondria from cytoplasm IS1112 were also distinguished by synthesis of an additional 12 000 mol. wt. polypeptide. Mitochondria from the cytoplasmic male sterile line Martin nucleus in 9E cytoplasm synthesised an additional 42 000 mol. wt. polypeptide but did not synthesise a 38 000 mol. wt. polypeptide detected in all other cytoplasms. Immunoprecipitation of mitochondrial translation products with antiserum raised against subunit I of yeast cytochrome oxidase tentatively identified the 38 000 mol. wt. polypeptide as subunit I of sorghum cytochrome oxidase. The 42 000 mol. wt. polypeptide was also immuno-precipitated by this antiserum and thus is probably an altered form of cytochrome oxidase subunit I.Analysis of native mitochondrial DNA by agarose gel electrophoresis revealed the presence of two plasmid-like DNA species of molecular weight 5.3 and 5.7 kb in the cytoplasmic male sterile lines Kafir nucleus in cytoplasm IS1112 and Yellow Feterita nucleus in M35-1 cytoplasm. Thus there is a positive correlation between the synthesis of the 82 000 mol. wt. polypeptide and the presence of the additional DNA species.     

An ecological study of the rare rotifer species Trochosphaera solstitialis (Thorpe 1893) and the first report of the male

An ecological study of the rotifer species Trochosphaera solstitialis (Thorpe, 1893) was conducted for a period of eight months in a temporary pond in eastern Texas, U.S.A. The pond was found to be environmentally stressed and contained large amounts of decomposing vegetation. Physico-chemical factors contributing to the stressed conditions were low dissolved oxygen concentrations, low pH values, high ammonia concentrations, and high color values caused by large concentrations of iron, tannin and lignin. Large concentrations of iron, tannin, and lignin seem to be highly correlated with T. solstitialis populations. Physicochemical conditions probably eliminated predators of the rotifer, such as fish. Males of T. solstitialis were observed which never left the body cavity of the female. Males probably do not feed with an apparent rudimentary digestive system.     

Ecdysterone antagonism,mimicry, and synergism of juvenile hormone action on the Monarch butterfly reproductive tract

Previous research on Monarch butterflies has shown that juvenile hormone (JH) stimulates the development of the ovary and certain reproductive glands of both sexes. Ecdysterone injections into intact Monarchs demonstrate that low doses of this hormone inhibit ovarian development, and higher doses stimulate the male and female reproductive glands. In addition, experiments using neckligatured adults show that ecdysterone stimulates the reproductive glands of both sexes, in the apparent absence of JH, with the most pronounced effect being observed on the female colleterial gland. Other studies with neck-ligatured animals demonstrate that ecdysterone also synergizes with JH on the female gland and all three male glands. The feasibility of using Monarch reproductive glands for studies on the mode of action and interaction of JH and ecdysterone, and the possibility of a rôle of ecdysterone in the normal regulation of Monarch oögenesis, are discussed.     

低温敏核不育水稻go543S育性对温、光的反应

以新型光温敏核不育（PTGMS,Photo-thermo sensitive genic male sterile)水稻go543S为材料,通过自然生态条件下和人工温、光处理条件下的育性观察,对其育性转换与温度和光周期的关系进行了研究。结果表明：go543S育性主要受温度控制,表现为低温条件下不育,高温条件下可育,育性转换的不育临界温度值为29．5℃,对温度传感的部位是幼穗,敏感时期为花粉母细胞形成致减数分裂,对应的剑叶叶枕距变化范围为－12．2－＋0．7cm;育性敏感期在人工恒温28．0℃条件下,无论长日（14－16h）或短日（10－12h）处理均表现不育,其不育性不受光周期影响,在人工恒温31.5℃条件下,无论长日还是短日处理均表现可育,但短日可明显提高其可育性。     

温度和种间竞争对大型溞种群动态和两性生殖的影响

在20℃、25℃下,将大型溞和老年低额溞分别按7+3(B组),5+5(C组),3+7(D组)的组合进行混合培养,以及用单种培养(10+0(A组),0+10(E组))作为对照,研究了温度和种间竞争对大型溞种群动态和两性生殖的影响.实验结果表明:在混合培养时,大型溞对老年低额溞产生明显的竞争优势.20℃、25℃下,单种培养的老年低额溞最大种群密度分别为大型溞的2.31和1.97,而在混合培养下老年低额溞的种群密度明显低于大型溞,在实验25d后几乎全部死亡.25℃下两种溞的种群密度之间存在极显著的负相关性(C组:r=-0.508,n=30,P<0.01;D组:r=-0.483,n=30,P<0.01).在20℃、单种培养下,大型溞在首次产幼溞时即出现雄体,且种群密度与雄体密度呈显著的相关性(r=0.678,n=24,P<0.01).大型溞的最大雄体密度(106 ind.(200ml)~(-1))和最大雄体比例(36.8%)均出现在20℃、单种培养下.25℃下,大型溞在混合培养的B组和C组首次产幼溞时即出现雄体,且雄体在混合培养B组的比例达28.2%.大型溞在25℃、单种培养下没有产生卵鞍,在混合培养下总计产生66个卵鞍,其中空卵鞍占51.5%,而在20℃、混合培养下没有卵鞍产生.实验结果暗示:在较高的温度下,种间竞争刺激了大型溞雄体的产生和卵鞍的形成,高密度的雄体有助于大型溞孤雌生殖雌体向两性生殖雌体的转化.     

蚜虫雄蚜与雌性母对性信息素及植物挥发物的田间反应

田间观察了桃蚜Myzus persicae (Sulzer)、绣线菊蚜Aphis spiraecola Patch 、山楂圆疣蚜Ovatus crataegarius (Walker)等3种蚜虫对性信息素[(4aS,7S,7aR)-荆芥内酯和 (1R,4aS,7S,7aR)-荆芥醇]的反应,并且调查了性信息素与植物挥发物对桃蚜的田间引诱活性的相互作用.在有冬寄主或夏寄主植物的田中,性信息素诱捕器诱捕到桃蚜雄蚜与雌性母的数量显著多于对照诱捕器的诱捕数;但在非寄主植物的田中,却引诱不到桃蚜.苯甲醛(冬寄主植物桃树Prunus persica的主要挥发物组分之一)能够增强桃蚜雄蚜的引诱作用.绣线菊蚜雄蚜和雌性母对植物中提取的荆芥内酯有反应,而山楂圆疣蚜雄蚜和雌性母对植物中提取的和人工合成的荆芥内酯都没有反应,但对荆芥醇有反应.并且在荆芥醇中添加荆芥内酯之后对山楂圆疣蚜雄蚜引诱活性显著提高.还讨论了雌性蚜产生化合物被雄蚜作为性信息素、被雌性母作为聚集信息素以及性信息素与寄主植物挥发物的相互作用.