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Diversity of nitrogen-fixing cyanobacteria under various ecosystems of Thailand: population dynamics as affected by environmental factors 总被引:4,自引:0,他引:4
Chunleuchanon Somporn Sooksawang Apichat Teaumroong Neung Boonkerd Nantakorn 《World journal of microbiology & biotechnology》2003,19(2):167-173
Investigation of N2-fixing cyanobacteria from Thai soil was carried out at 2-month intervals between July 1997 and November 1999 to determine the population number, population dynamics and favourable habitats. Sites were selected in three parts of Thailand; North, Central and Northeast. In each part, various soil ecosystems were used as sampling sites; at highest elevation as on the top of the mountain, in the middle and at the foot of the mountain, as well as in flat areas of agricultural practice and uncultivated areas. Generally, a high population of N2-fixing cyanobacteria was found in agricultural areas where rice cultivation was practised, rather than in other sites. The population dynamics in the mountain and uncultivated areas were less fluctuating than in agricultural areas. The population densities in agricultural areas increased in the rainy season and decreased during the dry season. Other environmental factors such as temperature, moisture and pH also affected the population densities in different habitats. Cyanobacterial diversity was notably influenced by the type of ecosystem in both dry and rainy seasons. The cultivation area containing rice in rotation with other crops contained the most genetically diverse range of species. 相似文献
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Teaumroong Neung Innok Sasidhorn Chunleuchanon Somporn Boonkerd Nantakorn 《World journal of microbiology & biotechnology》2002,18(7):673-682
The diversity among 853 isolates of nitrogen-fixing cyanobacteria obtained from soil samples collected from different ecosystems including mountainous, forest and cultivated areas in the central, northern and northeastern regions of Thailand was examined. Most isolates showed slow growth rate and had filamentous, heterocystous cells. The percentage of heterocysts in the filaments of different isolates varied from 8.3 to 9.6. Only a few strains showed high nitrogen-fixing potential, while most of the strains exhibited low capacity for nitrogen fixation. Anabaena and Nostoc were the dominant genera among these isolates. One hundred and two isolates were randomly selected from this diverse collection to determine the extent of genetic diversity on the basis of DNA fingerprinting using the PCR method. Based on the PCR products obtained by using a combination of three primers, all strains could be distinguished from one another. When a subset of 45 isolates of Nostoc and a subset of 44 isolates of Anabaena were further analysed by PCR, a wide range of diversity was observed within each of these genera. 相似文献
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Cyanobacterial akinete induction and its application as biofertilizer for rice cultivation 总被引:1,自引:0,他引:1
Sasidhorn Innok Somporn Chunleuchanon Nantakorn Boonkerd Neung Teaumroong 《Journal of applied phycology》2009,21(6):737-744
Nostoc sp. VICCR1-1 was induced in order to form akinetes on the basis of nutrient modification. Phosphorus and iron were found
to be the critical for akinete differentiation, especially when both elements were omitted. The number of akinete cells increased
up to 20% when compared with culturing in BG110 medium (without N source). In addition, CaCl2 played a role in heterocyst differentiation, and was able to induce heterocyst ranging between 30% and 46%. In order to prepare
akinetes as inoculum, the dried form of akinetes was prepared by mixing it with montmorillonite clay. The inoculum with the
amount of 2.8 × 106 cells m−2 was applied to rice (Oryza sativa) fields. After harvesting, the grain yields from chemical N fertilizer, vegetative cells, and akinete inoculum treatments
were not significantly different. To monitor the persistence of Nostoc sp. VICCR1-1 after harvesting, the most probable number-denaturing gradient gel electrophoresis technique using 16S rRNA
gene was employed. The results indicated that the remaining population is at 2.5 × 105 and 1.62 × 106 cells m−2 in treatments supplied with vegetative cells and akinete inocula, respectively. Akinete induction might be one of the appropriate
approaches for producing cyanobacterial inoculum. 相似文献
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