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Version 3.18
Publication Type J
Authors Zhang, S. R., J. Song, H. Wang and G. Feng
Title Effect of salinity on seed germination, ion content and photosynthesis of cotyledons in halophytes or xerophyte growing in Central Asia
Source Journal of Plant Ecology
Author Keywords cotyledonal chloroplast Haloxylon ammodendron Haloxylon persicum salinity seed germination Suaeda physophora haloxylon-ammodendron atriplex-centralasiatica suaeda-physophora sodium-chloride nacl stress plants ultrastructure chenopodiaceae chloroplasts accumulation
Abstract Aims We investigated the impact of salinity on seed germination, chlorophyll content, chloroplast structure and photosynthesis of the green embryos in desiccated seeds of the xerophyte Haloxylon persicum, xero-halophyte Haloxylon ammodendron and euhalophyte Suaeda physophora. Methods Seeds of H. persicum, H. ammodendron and S. physophora were collected from natural environment in Fukang, Xinjiang province. Pretreatment with 700 mM NaCl was carried out to stimulate the natural 'seed priming'; we analyzed the joint effect of salinity and different species on germination physiology and cotyledonal structure and photosynthetic function changes during germination and recovery stage. Important Findings We found that seeds did not suffer ion toxicity for the two halophytes H. ammodendron and S. physophora, as evidenced by the high final germination after ungerminated seeds pretreated with 700 mM NaCl were transferred to distilled water, but the final germination of the xerophyte H. persicum was significantly lower than that of control. The Na+ concentration in embryos increased under salinity for all species, while K+ concentration decreased by salinity only for H. persicum and H. ammodendron, i.e. the concentration of K+ in embryos of H. persicum and H. ammodendron decreased by 36% and 46%, respectively. For all species, whether dry intact seeds or cotyledons of dry seeds imbibed in deionized water and NaCl solution, had high chlorophyll content. Treatment with NaCl also caused chloroplast thylakoids to swell and chlorophyll content to decrease in seeds of H. persicum, but no significant change was observed in the more salt-tolerant species S. physophora and H. ammodendron. Fluorescence measurement showed that 700 mM NaCl decreased the Fv/Fm ratio of cotyledons in seeds for all species, especially for H. persicum and H. ammodendron. Photosynthetic oxygen releasing was detected from the seeds that were moistened with distilled water and 700 mM NaCl for 6 or 24 h and from the seeds that were initially moistened with 700 mM NaCl in darkness for 10 days, then transferred to distilled water for another 6 and 24 h. The results indicated that the chlorophyll in cotyledon of desiccated seed had photosynthetic function in early germination stage, even under high-saline condition. In addition, the photosynthesis of chlorophyll in the embryonic cotyledons of desiccated seeds during germination was similar to that in leaves of young seedlings for all species. In conclusion, the chloroplasts of the two halophytes were more salt resistant compared with the xerophyte H. persicum. The photosynthetic function of chlorophyll in cotyledons of mature seeds may be ecologically important for seedling development in early stage for plants growing in extremely saline or arid environments.
Author Address [Zhang, Shirong; Wang, He; Feng, Gu] China Agr Univ, Coll Resources & Environm Sci, Dept Plant Nutr, Beijing 100094, Peoples R China. [Song, Jie] Shandong Normal Univ, Dept Biol, Coll Life Sci, Jinan 250014, Peoples R China. Feng, G (reprint author), China Agr Univ, Coll Resources & Environm Sci, Dept Plant Nutr, Beijing 100094, Peoples R China. fenggu@cau.edu.cn
ISSN 1752-9921
ISBN 1752-9921
29-Character Source Abbreviation J. Plant Ecol.
Publication Date Dec
Year Published 2010
Volume 3
Issue 4
Beginning Page 259-267
Digital Object Identifier (DOI) 10.1093/jpe/rtq005
Unique Article Identifier WOS:000284502100004
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