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701.
The ascorbate system in recalcitrant and orthodox seeds 总被引:9,自引:0,他引:9
Recalcitrant seeds of Ginkgo biloba L., Quercus cerris L., Aesculus hippocastanum L. and Cycas revoluta Thunb. are shed by the plant at a high moisture content, contain a large amount of ascorbic acid (ASA) and maintain high ascorbate (ASC) peroxidase (EC 1.11.1.11) activity. Three proteins showing ASC peroxidase activity are present in G. biloba seeds. Conversely, dry orthodox seeds ( Vicia faba L., Avena sativa L., Pinus pinea L.) are completely devoid of ASA and ASC peroxidase. Experimentally induced rapid variations of the water level in both recalcitrant and orthodox seeds do not affect the ASC peroxidase; slow dehydration affects the ASC peroxidase activity moderately in recalcitrant seeds, but provokes a complete loss of germinability. Another peculiar difference between orthodox and recalcitrant seeds concerns the ascorbate recycling enzymes, ascorbate free radical (AFR) reductase (EC 1.6.5.4) and dehydroascorbate (DHA) reductase (EC 1.8.5.1). The DHA reduction capability is low in recalcitrant seeds, but is high in the orthodox ones. In contrast, AFR reductase activity is high in recalcitrant seeds and low in the orthodox ones. Data reported here concerning the ASC system appear to contribute to better understanding the recalcitrance. The presence of three different proteins showing ASC peroxidase activity in the archaic seed-bearing plant G. biloba and its involvement in the spermatophyte evolution is discussed. 相似文献
702.
Franca Valsecchi 《Plant biosystems》2013,147(1-3):43-47
Abstract SPARTINA JUNCEA WILLD.: A NEW SPECIES FOR SARDINIA. — The Author remarks the presence of a new species for Sardinia: Spartina juncea Willd at the month of Calich pool (Alghero) and on the neighbouring littoral, in a place reflecting its known edaphic necessities « sea dump sands and saltish marshes ». 相似文献
703.
704.
Abstract Regeneration and vegetative multiplication in ENTEROMORPHA COMPRESSA (L.) Grev. — Fragments of young filaments of Enteromorpha compressa were cultured in order to determine its regenerative and multiplicative power and time limit. The original fragments cultured in vitro produced a new strain of aposporical plants, by means of buds. These aposporical individuals, when grown up, bear rhizoids with propagula from which a new strain of free algs take place. The latter generation is supplied with a fixation apparatus and show regular shape and clear polarity. 相似文献
705.
706.
Zhang Lan Liu Xiaojuan Sun Zhenhua Bu Wensheng Bongers Franca J. Song Xiaoyang Yang Jie Sun Zhenkai Li Yin Li Shan Cao Min Ma Keping Swenson Nathan G. 《中国科学:生命科学英文版》2023,66(2):376-384
Science China Life Sciences - Plant communities in mountainous areas shift gradually as climatic conditions change with altitude. How trait structure in multivariate space adapts to these varying... 相似文献
707.
708.
Electron microscopy of the cells of the follicle duct of Triops cancriformis shows that the follicular ducts are lined by a single-layered epithelium which also produces the eggshell material. The cytoplasm is rich in rough endoplasmic reticulum that synthesizes the eggshell material which subsequently aggregates into preformed vacuoles. Newly formed spheres of eggshell material are then excreted into the lumen. At the end of vitellogenesis the oocytes descend toward the longitudinal oviduct and pass through the eggshell material which fills the follicle ducts. The production of the eggshell and its chemical composition in some Phyllopoda are compared. The paper discusses the relationship between the eggshell construction and the reproductive biology of the population. 相似文献
709.
Franca Dagna Bricarelli M. Fraccaro J. Lindsten U. Müller P. Baggio Laura Doria Lamba Carbone A. Hjerpe F. Lindgren Antonia Mayerová H. Ringertz E. M. Ritzén D. C. Rovetta C. Sicchero U. Wolf 《Human genetics》1981,57(1):15-22
Summary Three families with infants affected with campomelic dysplasia, a genetically determined mesenchymal disease frequently associated with sex reversal were studied. Two XY famales with ovarian gonadal differentiation and typical clinical features of campomelic dysplasia could be tested for H-Y antigen and were found to be H-Y negative. 相似文献
710.
Roberto Alves de Lima Nidia Cavalcanti Franca Pedro Diaz Diaz Otto R. Gottlieb 《Phytochemistry》1975,14(8):1831-1833
The trunk wood of Iryanthera coriacea Ducke (Myristicaceae) contains six compounds which belong to the recently discovered 1,3-diarylpropane type of flavonoids, 1-(2-hydroxy-4-methoxyphenyl)-3-(3,4-methylenedioxyphenyl)-propane, 1-(2,4-dihydroxyphenyl)-3-(3,4-methylenedioxyphenyl)-propane, 1-(4-methoxyphenyl)-3-(2-hydroxy-4,5-methylenedioxyphenyl)-propane, 1-(4-hydroxy-2-methoxy-phenyl)-3-(4-hydroxy-3-methoxyphenyl)-propane, 1-(2,4-dihydroxyphenyl)-3-(2-methoxy-4,5-methylene-dioxyphenyl)-propane, 1-(2,4-dihydroxy-3,5-methylphenyl)-3-(2-hydroxy-4,5-methylenedioxyphenyl)-propane. 相似文献