کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1589401 | 1001990 | 2010 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effects of UVB radiation on the agarophyte Gracilaria domingensis (Rhodophyta, Gracilariales): Changes in cell organization, growth and photosynthetic performance
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Effects of UVB radiation on the agarophyte Gracilaria domingensis (Rhodophyta, Gracilariales): Changes in cell organization, growth and photosynthetic performance Effects of UVB radiation on the agarophyte Gracilaria domingensis (Rhodophyta, Gracilariales): Changes in cell organization, growth and photosynthetic performance](/preview/png/1589401.png)
چکیده انگلیسی
The effects of ultraviolet radiation-B (UVBR) in apical segments of the red macroalgae Gracilaria domingensis (Kützing) Sonder ex Dickie were examined in vitro. Over a period of 21 days, the segments were cultivated and exposed to photosynthetically active radiation (PAR) at 80 μmol photons mâ2 sâ1 and PAR + UVBR at 1.6 W mâ2 for 3 h per day. The samples were processed for electron microscopy, as well as histochemical analysis, and growth rate, photosynthetic pigment contents and photosynthetic performance were measured. Toluidine Blue reaction showed metachromatic granulations in vacuole and lenticular thickness, while Coomassie Brilliant Blue showed a higher concentration of cytoplasmic organelles, and Periodic Acid Schiff stain showed an increase in the number of floridean starch grains. UVBR also caused changes in the ultrastructure of cortical and subcortical cells, which included an increased number of plastoglobuli, changes in mitochondrial organization, destruction of chloroplast internal organization, and the disappearance of phycobilisomes. The algae cultivated under PAR-only showed growth rates of 6.0% dayâ1, while algae exposed to PAR + UVBR grew only 2.8% dayâ1. Compared with algae cultivated with PAR-only, the contents of photosynthetic pigments, including chlorophyll a, phycoerythrin, phycocyanin and allophycocyanin, decreased after exposure to PAR + UVBR, and significant differences were observed. Finally, analysis of these four photosynthetic parameters also showed reduction after exposure to PAR + UVBR: maximum photosynthetic rate, photosynthetic efficiency, photoinhibition and relative electron transport rate. Taken together, these findings strongly suggested that UVBR negatively affects the agarophyte G. domingensis.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Micron - Volume 41, Issue 8, December 2010, Pages 919-930
Journal: Micron - Volume 41, Issue 8, December 2010, Pages 919-930
نویسندگان
Ãder C. Schmidt, Rodrigo dos Santos, Paulo A. Horta, Marcelo Maraschin, Zenilda L. Bouzon,