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-pollen have been largely unsuccessful (reviewed by Santamour, 1967 ). The main mode of reproduction for georgia plume is thought to be vegetative through root suckers, but plant regeneration is extremely limited. Low population numbers and a lack of sexual

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; Ristaino, 1990 ). Sexual reproduction augments genetic variation in P. capsici via allelic recombination. The resulting offspring genotypes may include acquired resistance to fungicides or antibiotics, creating new challenges for phytophthora blight

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Anthers contain starch and neutral lipids, which have key roles in microspore ontogeny and gametophyte development. In this study, we observed the dynamic changes in starch and neutral lipids in the anther developmental processes of castor (Ricinus communis) by cytochemical methods. Starch grains and neutral lipids presented a regular dynamic distribution during anther development. In young anthers, some neutral lipids accumulated in sporogenous cells, whereas neutral lipids disappeared with microspore growth. At the late microspore stage, starch grains began to accumulate in microspores, and the starch content of bicellular pollen significantly increased after microspore mitosis. At anthesis, starch grains and neutral lipids accumulated in the mature pollen grains. Visible changes occurred in anther wall cells. The epidermis, middle layer, and tapetum were degenerated, and only a single layer of endothecium remained at anthesis. The dynamic variation of starch grains and neutral lipids in tapetal cells was consistent with the changes in microspores and pollen during anther development. All these findings demonstrated that tapetal cells directly interacted with the developing gametophytes. The tapetal cells play an important role in supplying nutritional substances for microspore absorption. Moreover, the endothecium protects the pollen and contributes to anther dehiscence. The results of this study provide a foundation for the further research on sexual reproduction in angiosperms.

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Cranberry (Vaccinium macrocarpon Ait.) has the opportunity to partition resources into sexual and/or asexual (stolons) modes of reproduction. Nitrogen status has been shown to impact the degree of stoloniferous growth. To determine whether there is a genotypic response to varying nitrogen levels, six hybrid and four native cultivars were treated with three annual rates of nitrogen fertilizer (17, 34, or 67 kg·ha-1) for 4 years. Fruit yield was determined each year and asexual vegetative growth (stolons) weight was removed and measured in all but the first year of the experiment. Cultivars exhibited different patterns of yield and stolon weight response over the three nitrogen rates. Not all cultivars exhibited significant yield decreases at the high N levels. Vegetative growth (stolon weight) generally increased with increasing N, however, not all cultivars responded similarly over three N rates. Partitioning between yield and stolon production favored fruit yield at the lower N rates in three of the four native cultivars studied (`Cropper', `Early Black', and `Howes'). Yield over N rates was more stable for four of the six hybrid cultivars, which may be the result of greater heterozygosity in hybrids than natives, and/or genetic gain from one breeding and selection cycle, offering increased tolerance to nitrogen stress. This study indicates that genetic variation exists for yield, yield stability, and stolon production relative to nitrogen level, and that genetic gain in cranberry is possible for these traits. Future studies involving cranberry physiology and nutrition should consider the genotypes used.

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three to five with slender styles; stamens usually number five per flower. Anthesis occurs in late April to May. Little research has been published on Z. americanum in general and even less so on its sexual reproduction. Although there has been some

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event in plant sexual reproduction and has become an important topic in studies on plant embryology. Since the first report describing double fertilization, great progress has been made in many studies. For the study of male and female germ units, the

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, 1967 ). In flowering plants, calcium plays crucial roles in regulating sexual reproduction processes such as pollen germination, pollen tube growth ( Cardenas et al., 2008 ; Franklin-Tong, 1999 ; Hepler, 1997 ; Heslop-Harrison, 1987 ; Kwack, 1967

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dodecaploid ( Table 1 ). Interestingly, A. donax in Australia was reported to have 2 n = 84 ( Haddadchi et al., 2013 ) further indicating sources of genetic diversity. The nonreduction of chromosomes during meiosis (i.e., during sexual reproduction) is

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adequate number of sperm and egg cells can be isolated, allowing for transcriptomics research into fertilization of pepper. This provides entry into a new field of the research into the sexual reproduction of dicotyledonous pepper. Sperm cell isolation from

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Meiosis is a specialized cell division essential for sexual reproduction. It involves a single DNA replication event followed by two rounds of chromosome segregation- meiosis I (M I) and meiosis II (M II) – to produce cells with half the chromosome

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