The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Xiangyang Kang - One of the best experts on this subject based on the ideXlab platform.
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Induction of 2n female gametes in rubber ( Hevea brasiliensis ) by high-temperature exposure during Megasporogenesis as a basis for triploid breeding
Tree Genetics & Genomes, 2020Co-Authors: Peng-qiang Yao, Yan-fen Qiu, Xiangyang KangAbstract:In this study, 2n gametes were induced in the rubber tree RRIM 600 by high-temperature exposure and used for the production of triploid offspring. A relationship between Megasporogenesis and the external morphology of male and female flower buds was established to guide the treatments. The relationship between Megasporogenesis and microsporogenesis of adjacent male flower buds was also estimated. The developmental stage of Megasporogenesis was estimated indirectly based on these relationships. Finally, 5 open-pollinated triploid offspring were obtained; the mean efficiency of triploid production was approximately 1.2%. The induction efficiency was approximately 9.1% when meiotic stages of Megasporogenesis from the diplotene stage to the diakinesis stage were exposed to a high temperature of 44 °C for 4 h. Simple sequence repeat (SSR) markers revealed that the 2n gametes were derived from the RRIM 600 female parent. This study was the first to induce 2n female gametes in rubber trees and will serve as the basis for the germplasm creation of triploids and breeding of new varieties of rubber trees.
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megaspore chromosome doubling in eucalyptus urophylla s t blake induced by colchicine treatment to produce triploids
Forests, 2018Co-Authors: Jun Yang, Jianzhong Wang, Tao Xiong, Yun Li, Xiangyang KangAbstract:Triploids generally provide an advantage in vegetative growth in forest trees. However, the technique of triploid breeding is still an open field in the Eucalyptus tree species. This study aims to explore the colchicine treatment technique for megaspore chromosome doubling to establish triploids in this tree species. Cytological observation on microsporogenesis and Megasporogenesis was carried out to guide megaspore chromosome doubling induced by colchicine treatment. Ploidy level in progenies was detected by flow cytometry and somatic chromosome counting. A relationship between microsporogenesis and Megasporogenesis was established to guide the colchicine treatment. Seven triploids were obtained in the progenies, and the highest efficiency of triploid production was 6.25% when the flower buds underwent a 0.25% colchicine solution treatment for 6 h using an aspiration method seven days after the first observation of leptotene during microsporogenesis on the floral branch. Cytological analysis showed that the megasporocyte from leptotene to diakinesis may be the optimal period for megaspore chromosome doubling by colchicine treatment. Plant height, ground diameter, leaf area, and the photosynthetic parameter of triploid eucalypt were significantly higher than those of the diploid plant at 6 months old. Hybridization with 2n megaspores induced by colchicine treatment is an effective way for Eucalyptus triploid breeding. These results should accelerate the development of advanced germplasms in this tree species.
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Induction of unreduced megaspores with high temperature during Megasporogenesis in Populus
Annals of Forest Science, 2011Co-Authors: Jun Wang, Xiangyang KangAbstract:Introduction Triploid breeding is one of the most powerful approaches for improvement of the genus Populus L. Pollination with artificial unreduced (2n) pollen was inefficiency, owing to weak competition of 2n pollen. To induce 2n megaspores and improve the efficiency of triploid production, female buds of Populus pseudo-simonii × Populus nigra ‘Zheyin3#’ were exposed to high temperature during Megasporogenesis.
Xiaoming Pang - One of the best experts on this subject based on the ideXlab platform.
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Megasporogenesis microsporogenesis and female and male gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Xiang Li, Feiyi Huang, Xiaoming Pang, Yingyue LiAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the Megasporogenesis, microsporogenesis, and female and male gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of Megasporogenesis, microsporogenesis, and female and male gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
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Megasporogenesis microsporogenesis and female and male gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Ye Guo, Feiyi Huang, Xiaoming PangAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the Megasporogenesis, microsporogenesis, and female and male gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of Megasporogenesis, microsporogenesis, and female and male gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
Yingyue Li - One of the best experts on this subject based on the ideXlab platform.
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Megasporogenesis microsporogenesis and female and male gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Xiang Li, Feiyi Huang, Xiaoming Pang, Yingyue LiAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the Megasporogenesis, microsporogenesis, and female and male gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of Megasporogenesis, microsporogenesis, and female and male gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
Feiyi Huang - One of the best experts on this subject based on the ideXlab platform.
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Megasporogenesis microsporogenesis and female and male gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Xiang Li, Feiyi Huang, Xiaoming Pang, Yingyue LiAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the Megasporogenesis, microsporogenesis, and female and male gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of Megasporogenesis, microsporogenesis, and female and male gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
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Megasporogenesis microsporogenesis and female and male gametophyte development in ziziphus jujuba mill
Protoplasma, 2019Co-Authors: Ye Guo, Feiyi Huang, Xiaoming PangAbstract:Jujube (Ziziphus jujuba Mill.) is an important fruit tree species in China. In this study, we studied the Megasporogenesis, microsporogenesis, and female and male gametophyte development of two major jujube cultivars, “Dongzao” and “Mayazao,” using the squash technique, improved paraffin section technology, and optical microscopy. Our investigation revealed that both “Dongzao” and “Mayazao” have bilocular ovaries, basal placenta, and anatropous, bitegmic, crassinucellate ovules. The tetrads formed by meiosis of megaspore mother cells are arranged in a straight line or a tetrahedron. Embryo sac development is of the Polygonum type. The flower buds contain five anthers, each having four pollen sacs. The anther wall, which is of the fundamental form, is composed of epidermis, endothecium, one or two middle layers, and glandular tapetum. Mature pollen grains are two-celled and three-colporate. Both “Dongzao” and “Mayazao” can form normal mature pollen grains. Our study, which has revealed the basic phenomena and progression of Megasporogenesis, microsporogenesis, and female and male gametophyte development in jujube, has generated important data for further research on jujube cytology and reproductive biology. Finally, our explorations of the cytological mechanism of male sterility in “Dongzao” also have provided a cytological basis for crossbreeding.
Yves Savidan - One of the best experts on this subject based on the ideXlab platform.
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Megasporogenesis and megagametogenesis in several Tripsacum species (Poaceae)
American Journal of Botany, 1995Co-Authors: Olivier Leblanc, John G. Carman, Michael D. Peel, Yves SavidanAbstract:The Tripsacuin agamic complex (x = 18) will provide valuable characters for maize breeding, provided that apomixis can be manipulated. Apomixis in Tripsacuin was first reported 40 years ago, but its prevalence in the genus has not been established. Reproductive development was determined for eight Mexican and two South American Tripsacuin species by microscopic analysis of ovaries cleared in a benzyl benzoate-dibutyl phthalate solution using interference contrast optics. The occurrence and distribution of callose deposition during Megasporogenesis were determined by fluorescence microscopy of ovaries optically cleared in an aqueous sucrose solution containing aniline blue. Diploid genotypes were sexual. Polyploid forms reproduced apomictically following the Antennaria type (complete meiosis abortion) of diplospory. The Taraxacum type (unreduced megaspore production through meiotic restitution nuclei) of diplospory also occurred but rarely. The walls of diplosporic megasporocytes lacked callose whereas the walls of sexual megasporocytes contained a normal complement of callose. The absence of callose suggests that the diplosporic forms of reproduction result from mutations affecting the normal meiotic process. Apomixis in the Tripsacurn genus is facultative, and the production of new polyploid genotypes through genetic exchanges involving both apomictic and sexual genotypes is possible.