Behavioral,physiological, and morphological components of dominance and mate attraction in male green iguanas

This study investigated the morphological, physiological, and behavioral components of social dominance important for mate attraction in male green iguanas (Iguana iguana). A group of 9 male and 11 female adult green iguanas was studied in a large semi-natural enclosure during one reproductive season (October–January). Four of the nine males never initiated aggressive encounters; the other five were observed to display aggressively toward each other and were ranked in a linear dominance hierarchy. Head size was the most important factor influencing fighting success. Head size and display frequency were positively correlated with plasma testosterone levels. Dominance rank directly influenced ability to monopolize areas containing resources used by females. The quality of a male's home range, measured as his access to a large basking rock in the enclosure, was related to the proportion of potential mates found within his home range. One male greatly surpassed the others in his ability to defend a home range of high quality and attract potential mates. These data suggest that physiological and morphological factors, through their influence on social behavior, may ultimately affect male reproductive fitness. © 1992 Wiley-Liss, Inc.     

Restoration of normal stamen development and pollen formation by fusion of different cytoplasmic male-sterile cultivars of Nicotiana tabacum

Summary Fusion of two cytoplasmic male-sterile cultivars of Nicotiana tabacum, one with N. bigelovii cytoplasm and one with N. undulata cytoplasm, resulted in the restoration of male fertility in cybrid plants. All male-fertile cybrids exhibited fused corollas, which is characteristic for the cultivar with N. undulata cytoplasm, while their stamen structures varied from cybrid to cybrid, some producing stamens with anthers fused to petal-like appendages and one producing stamens of a normal appearance for N. tabacum. Restriction enzyme digestion and agarose gel electrophoresis of mitochondrial DNA showed that mitochondrial DNA of the fertile cybrids was more similar to the male-sterile cultivar with the cytoplasm of N. undulata than to the cultivar with N. bigelovii cytoplasm. Some restriction fragments were unique to the male-fertile cybrids. Comparisons between stamen structure and mitochondrial DNA for eight fertile progeny from one cybrid plant led to the identification of several restriction fragments that appeared at enhanced levels in connection with normal stamen development.     

Structural studies of microsporogenesis in fertile and male-sterile onions (Allium cepa L.) containing the cms-S cytoplasm

Summary The structure of anther tissues has been studied during microsporogenesis in male-sterile and -fertile onions. Three types of abnormal tapetal behaviour have been observed within the single line II/3ms containing the cms-S cytoplasm: type 1, the premature breakdown of the tapetum at the tetrad stage, type 2, the hypertrophy of the tapetum after the diad stage followed by its premature autolysis and, type 3, in which the tapetum remains in good condition but for an abnormally long period of time. Tapetal autolysis proceeds in the same manner in both male-steriles and -fertiles with only the stage at which it occurs differing between the types of plants. Mitochondria were prominent in the tapetal tissue of all onion types throughout all stages of microsporogenesis and were still visible during the last stages of tapetal autolysis. In a detailed study of type 2 behaviour, no differences in mitochondrial volumes were found until the tapetum hypertrophied.     

Male sterility and restored fertility in annual mercuries, relations with sex differentiation

The paper summarizes the researches conducted on male sterility in Mercurialis annua. Totally sterile individuals are very scarce in the dioecious species showing as the other Mercuries, unisexual flowers devoid of rudiments of the opposite sex. From one sterile male mutant, a ‘sterile series’ was conducted and genetics was studied. Sterile, semisterile, restored fertile male lines were constructed as well as female lines containing the inducer gene of male sterility, both fertility restorers and the sensitive cytoplasm. Morphology and ontogeny of these isogenic lines were presented. Male sterile anthers (empty) present a splitted tapetum and an abnormal meiotic end. Restored fertile male lines were normal. The relative abundance of auxin and cytokinins was studied. A specific cytokinin pathway measured as a background in fertile lines, the cis-oxidized pathway characterised the ‘sterile series’. Restoration of normal meiosis and tapetum appeared for the highest quantities of cis-zeatin (669 ng instead of 192 ng/100 g fresh weight in totally sterile). Auxin quantities were abundant compared with the normal males. Gene expression in the ‘sterile series’ was also compared with the fertile lines. t-RNAs specific for normal females were expressed in the male ‘sterile series’. Hybridization kinetics and in vitro translations pf poly(A)⁺RNAs demonstrate specific sequences for each line. Comparisons between identical organs (normal fertile male/restored fertile male or normal female/female of the ‘sterile series’) exhibited nearly 10% differences. The results suggest that for stamen development, a cascade of regulators probably exists: sex genes acting on the induction of stamen or pistil, then genes for sterility/restoration of fertility acting in anthers. Fertility-sterility regulators control the synthesis of a specific cytokinin pathway. The new hormonal signals are linked to several specific genes expressed in the floral morphology characterizing each line of the ‘sterile series’.     

雄性生殖单位研究的回顾和展望

本文扼要回顾和评述了雄性生殖单位的发现、意义和研究进展,并对目前存在的问题和今后的研究进行了讨论和展望。     

Ultrastructural aspects of cytoplasmic male sterility inPetunia hybrida

Summary Anther development of isogenic male fertile and cytoplasmic male sterile types ofPetunia hybrida cv. Blue Bedder is studied by electron microscopy. First deviation in sporogenesis of the sterile type, is observed during leptotene stage of the meiocytes. Initial aberration is represented by the presence of large vacuoles in the cytoplasm of the tapetal cells. These vacuoles reveal the first aspects of degeneration; no other ultrastructural differences are observed. Vacuolation is accompanied by the condensation of cytoplasmic organelles. The tapetal cells become distorted and ultrastructural aberrations in mitochondria do occur. The mitochondria elongate and contain several tubular cristae.Substantial evidence suggests, that cytoplasmic male sterility in petunia is encoded by the mitochondrial genome (Boeshore el al. 1983). However, before degeneration becomes manifest, no consistent ultrastructural differences in mitochondrial organization are observed.Abortion of the tapetum and the sporogenous tissue in cytoplasmic male sterile plants, generally follows a corresponding pattern. Ultimately, the cells are highly distorted, the nucleus is disrupted and the cytoplasm disorganized. Mitochondria and plastids degenerate and many lipid droplets are present.     

Fertility restoration and mitochondrial nucleic acids distinguish at least five subgroups among cms-S cytoplasms of maize (Zea mays L.)

Summary Differences in fertility restoration and mitochondrial nucleic acids permitted division of 25 accessions of S-type male sterile cytoplasm (cms-S) of maize into five subgroups: B/D, CA, LBN, ME, and S(USDA). S cytoplasm itself (USDA cytoplasm) was surprisingly not representative of cms-S, since only two other accessions, TC and I, matched its mitochondrial DNA pattern. CA was the predominant subgroup, containing 18 of the 25 accessions. The B/D and ME subgroups were the most fertile and LBN the most sterile. The exceptional sterility of LBN cytoplasm makes it the most promising of the 25 cms-S accessions for the production of hybrid seed. The most efficient means of quantifying the fertility of the subgroups was analysis of pollen morphology in plants having cms-S cytoplasm and simultaneously being heterozygous for nuclear restorer-of-fertility (Rf) genes. This method took advantage of the gametophytic nature of cms-S restoration. The inbred NY821LERf was found to contain at least two restorer genes for cms-S. Fertility differences were correlated with mitochondrial nucleic acid variation in the LBN, ME, and S (USDA) subgroups.Paper No. 9498 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC     

Progressions of adult male chacma baboons (Papio ursinus) in the moremi wildlife reserve

It has been suggested that the sociospatial organization of baboon progressions has a protective function in which the most physically powerful troop members, the adult males, play a key role. This theory implies regularities in adult male progression order for different species of savannah baboons with similar social systems. Quantitative progression data are available from two such similar baboon species, olive and yellow, but not from the third, chacma. The order of movement of 15 adult male chacma baboons was determined from 40 progressions observed at the Moremi Wildlife Reserve, Botswana. The chacma males were most often found in the front sixth of progressions, next most often in the second sixth, and about equally often from there to the rear. As expected from the protection theory, this frontal positioning is consistent with available quantitative data from other species of savannah baboons.     

Increasing the variability of Lycopersicon peruvianum Mill. by protoplast fusion with Petunia hybrida L.

Somatic hybridization of Lycopersicon peruvianum and Petunia hybrida was carried out to transfer cytoplasmic male sterility from Petunia to Lycopersicon. Cytological, morphological and biochemical analyses were performed to characterize the regenerated plants. Two regenerated plants, R₃ and R₆, were male sterile. R₃ possessed chromosomes morphologically similar to those of both parental types. Leaf morphologies of these two plants and a third plant, R₇, were intermediate between the two parents. The stability of RUBPCase was verified during parental plant development and after in vitro culture. Plant R₇ presented a new form of the large subunit of RUBPCase.