The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the...The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the understanding of sucrose metabolism in microspores and the supporting tissues. The aims of the present work were to 1) follow the changes in total and relative concentrations of sucrose, glucose, fructose and starch in the stamen parts and microspores up until anthesis, 2) follow the activities of sucrose-metabolism-related enzymes, in the anther walls fraction and microspores of the crop plant tomato. Sucrose was found to be partially cleaved in the filament, decreasing by more than twofold in the anther wall layers and the locular fluid, and to accumulate in the mature pollen grains, constituting 80% of total soluble sugars. Thus, sucrose was both the starting sugar, supporting microspore development, and the main carbohydrate accumulated at the end of the pollen-development program. The major invertase found to be active in both the anther wall layers and in maturing microspores was cell-wall-bound invertase. High fructokinase 2 and sucrose phosphate synthase activities during pollen maturation coincided with sucrose accumulation. The potential importance of sucrose accumulation during pollen dehydration phase and germination is discussed.展开更多
Selaginella is the largest and most taxonomically complex genus in lycophytes.The fact that over 750 species are currently treated in a single genus makes Selaginellales/Selaginellaceae unique in pteridophytes.Here we...Selaginella is the largest and most taxonomically complex genus in lycophytes.The fact that over 750 species are currently treated in a single genus makes Selaginellales/Selaginellaceae unique in pteridophytes.Here we assembled a dataset of six existing and newly sampled plastid and nuclear loci with a total of 684 accessions(74%increase of the earlier largest sampling)representing ca.300 species to infer a new phylogeny.The evolution of 10 morphological characters is studied in the new phylogenetic context.Our major results include:(1)the nuclear and plastid phylogenies are congruent with each other and combined analysis well resolved and strongly supported the relationships of all but two major clades;(2)the Sinensis group is resolved as sister to S.subg.Pulviniella with strong support in two of the three analyses;(3)most morphological characters are highly homoplasious but some characters alone or combinations of characters well define the major clades in the family;and(4)an infrafamilial classification of Selaginellaceae is proposed and the currently defined Selaginella s.l.is split into seven subfamilies(corresponding to the current six subgenera t the Sinensis group)and 19 genera(the major diagnosable clades)with nine new species-poor genera.We support the conservation of Selaginella with a new type,S.flabellata,to minimize nomenclatural instability.We provide a key to subfamilies and genera,images illustrating their morphology,their morphological and geographical synopses,a list of constituent species,and necessary new combinations.This new classification will hopefully facilitate communication,promote further studies,and help conservation.展开更多
Populus bolleana is a variety of P. alba, commonly used in poplar breeding programs in China. Developmental biology that involves staminate flowers, microsporogenesis and microgametogenesis ofP. bolleana is essential ...Populus bolleana is a variety of P. alba, commonly used in poplar breeding programs in China. Developmental biology that involves staminate flowers, microsporogenesis and microgametogenesis ofP. bolleana is essential for Populus improvement in cross breeding for better characteristics in sexual reproduction. Flower morphology and pollen development were described and illustrated using anatomical, sectioning and stain-clearing techniques. The results show that microsporocytes undergo a regular meiotic process, but some multi-nucleate microspores occur at the microspore stage. It takes five days for microsporocytes to develop to mature pollen by forcing flower branches under greenhouse conditions. Additionally, an important relationship was found between stages of meiosis and anther colors. Microspore tetrads formed when the anther color turned yellow, whereas, when the pollen matured, the anther was red and the tapetum degenerated completely. When mature pollen grains are formed, flower buds develop into male catkins. In the end, filament elongated and pollen grains were released from dehisced anthers.展开更多
Information from previously published studies that are basic to this study is: 1) Following isolated barley microspore culture, around 80% of the resulting barley plants are completely fertile and genetically
To facilate breeding process of Brassica napus,a microspore culture and molecular marker-assisted screening combined system were proposed in this research.At early flowering stage,F1 offspring of hybridized combinatio...To facilate breeding process of Brassica napus,a microspore culture and molecular marker-assisted screening combined system were proposed in this research.At early flowering stage,F1 offspring of hybridized combination HY15 A×HF06 was used as donor for microspore culture to analyze effects of colchicine concentration on embryogenic and diploid rates of microspore.Treatment with 50 mg/L colchicine resulted in embryogenic rate of3.56 embryos/bud,which was substantially higher than control(0.78 embryos/bud).A total of 1,387 embryos and 862 single plants were obtained after induction culture.Ploidy detection was performed for the regenerated plants by flow cytometry.Diploid rates of microspores treated with 50 mg/L and 70 mg/L colchicine were 17.2%and 21.0%respectively,which was significantly higher than control(10.5%).Totally 108 single plants that doubled successfully were randomly selected and screened using molecular marker BE10.Approximately 54 of108 plants generated a 305 bp amplification product,whereas the other 54 plants showed a 398 bp band,thereby satisfying 1:1 separation ratio(x0.052=0.0093).These coincided with field identification results.Findings of this study indicated that homozygous breeding material could be obtained by microspore culture in a short time,thereby remarkably accelerate breeding.展开更多
文摘The formation of mature and fertile pollen grains, taking place inside the anther, depends on supply of assimilates, in the form of sucrose, provided mainly by the leaves. Data is limited, however, with respect to the understanding of sucrose metabolism in microspores and the supporting tissues. The aims of the present work were to 1) follow the changes in total and relative concentrations of sucrose, glucose, fructose and starch in the stamen parts and microspores up until anthesis, 2) follow the activities of sucrose-metabolism-related enzymes, in the anther walls fraction and microspores of the crop plant tomato. Sucrose was found to be partially cleaved in the filament, decreasing by more than twofold in the anther wall layers and the locular fluid, and to accumulate in the mature pollen grains, constituting 80% of total soluble sugars. Thus, sucrose was both the starting sugar, supporting microspore development, and the main carbohydrate accumulated at the end of the pollen-development program. The major invertase found to be active in both the anther wall layers and in maturing microspores was cell-wall-bound invertase. High fructokinase 2 and sucrose phosphate synthase activities during pollen maturation coincided with sucrose accumulation. The potential importance of sucrose accumulation during pollen dehydration phase and germination is discussed.
基金partially supported by the Natural Science Foundation of China (#31900186,#32260050)Yunnan Fundamental Research Projects (Grant NO.202301BF07001-016)the Glory Light International Fellowship for Chinese Botanists at Missouri Botanical Garden (MO) to X.M.Zhou
文摘Selaginella is the largest and most taxonomically complex genus in lycophytes.The fact that over 750 species are currently treated in a single genus makes Selaginellales/Selaginellaceae unique in pteridophytes.Here we assembled a dataset of six existing and newly sampled plastid and nuclear loci with a total of 684 accessions(74%increase of the earlier largest sampling)representing ca.300 species to infer a new phylogeny.The evolution of 10 morphological characters is studied in the new phylogenetic context.Our major results include:(1)the nuclear and plastid phylogenies are congruent with each other and combined analysis well resolved and strongly supported the relationships of all but two major clades;(2)the Sinensis group is resolved as sister to S.subg.Pulviniella with strong support in two of the three analyses;(3)most morphological characters are highly homoplasious but some characters alone or combinations of characters well define the major clades in the family;and(4)an infrafamilial classification of Selaginellaceae is proposed and the currently defined Selaginella s.l.is split into seven subfamilies(corresponding to the current six subgenera t the Sinensis group)and 19 genera(the major diagnosable clades)with nine new species-poor genera.We support the conservation of Selaginella with a new type,S.flabellata,to minimize nomenclatural instability.We provide a key to subfamilies and genera,images illustrating their morphology,their morphological and geographical synopses,a list of constituent species,and necessary new combinations.This new classification will hopefully facilitate communication,promote further studies,and help conservation.
基金supported by the National Natural Science Foundation of China(Grant No.30471407)the Graduate Student Foundation of Beijing Forestry University(No.0@008).
文摘Populus bolleana is a variety of P. alba, commonly used in poplar breeding programs in China. Developmental biology that involves staminate flowers, microsporogenesis and microgametogenesis ofP. bolleana is essential for Populus improvement in cross breeding for better characteristics in sexual reproduction. Flower morphology and pollen development were described and illustrated using anatomical, sectioning and stain-clearing techniques. The results show that microsporocytes undergo a regular meiotic process, but some multi-nucleate microspores occur at the microspore stage. It takes five days for microsporocytes to develop to mature pollen by forcing flower branches under greenhouse conditions. Additionally, an important relationship was found between stages of meiosis and anther colors. Microspore tetrads formed when the anther color turned yellow, whereas, when the pollen matured, the anther was red and the tapetum degenerated completely. When mature pollen grains are formed, flower buds develop into male catkins. In the end, filament elongated and pollen grains were released from dehisced anthers.
文摘Information from previously published studies that are basic to this study is: 1) Following isolated barley microspore culture, around 80% of the resulting barley plants are completely fertile and genetically
基金supported by the Youth Talent Development Plan of Shanghai Municipal Agricultural System,China(No.20180103)the National Key Research and Development Program of China(No.2018YFD0100602)the Youth Talent Running Plan of Shanghai Academy of Agricultural Sciences,China(No.2017020)。
文摘To facilate breeding process of Brassica napus,a microspore culture and molecular marker-assisted screening combined system were proposed in this research.At early flowering stage,F1 offspring of hybridized combination HY15 A×HF06 was used as donor for microspore culture to analyze effects of colchicine concentration on embryogenic and diploid rates of microspore.Treatment with 50 mg/L colchicine resulted in embryogenic rate of3.56 embryos/bud,which was substantially higher than control(0.78 embryos/bud).A total of 1,387 embryos and 862 single plants were obtained after induction culture.Ploidy detection was performed for the regenerated plants by flow cytometry.Diploid rates of microspores treated with 50 mg/L and 70 mg/L colchicine were 17.2%and 21.0%respectively,which was significantly higher than control(10.5%).Totally 108 single plants that doubled successfully were randomly selected and screened using molecular marker BE10.Approximately 54 of108 plants generated a 305 bp amplification product,whereas the other 54 plants showed a 398 bp band,thereby satisfying 1:1 separation ratio(x0.052=0.0093).These coincided with field identification results.Findings of this study indicated that homozygous breeding material could be obtained by microspore culture in a short time,thereby remarkably accelerate breeding.
