Ecology of deepwater rice-fields in Bangladesh 3. Associated algae and macrophytes

Whitton, Brian A.; Aziz, Abdul; Kawecka, Barbara; Röther, Joachim

doi:10.1007/bf00007931

Cited by 41 publications

(31 citation statements)

References 7 publications

(11 reference statements)

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“…Cyanobacteria are known to inhabit a range of habitats, including plant surfaces [4][5][6], but this has not been adequately explored for improving their biofertilizing potential in agriculture and the rhizosphere is a relatively unexplored frontier. Watanabe and co-workers [7] observed that the associative nitrogen fi xation of the rhizosphere was too low to meet the nitrogen demand of rice crop.…”

Section: Introductionmentioning

confidence: 99%

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

et al. 2009

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This investigation was undertaken to characterize the abundance and genera-wise diversity of cyanobacteria in the rice rhizosphere and nitrogen-fi xing ability of the isolated strains. The cyanobacterial strains belonging to the genera Nostoc and Anabaena comprised 80% of the rhizosphere isolates, which were also effi cient in enhancing the germination and growth of wheat seeds and exhibited signifi cantly high protein accumulation and IAA production. Distinct profi les for the cyanobacterial strains were obtained on amplifi cation with extended Hip 1 primer -HipTG, indicative of the diversity among these strains. Our investigation helped in identifying promising cyanobacterial isolates from the rhizosphere of rice, which can be utilized in developing effi cient plant growth promoting cyanobacterial inoculants.

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Section: Introductionmentioning

confidence: 99%

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

et al. 2009

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“…Previous studies on epiphytic cyanobacteria in rice fields have been performed only in deep-water rice fields, where these organisms are associated with deep-water rice tillers (2,34,35). In shallow-water rice fields only benthic and planktonic communities have been considered (14,20,27).…”

Section: Discussionmentioning

confidence: 99%

Epiphytic Cyanobacteria onChara vulgarisAre the Main Contributors to N₂Fixation in Rice Fields

Ariosa

Quesada

Aburto

et al. 2004

Appl Environ Microbiol

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The distribution of nitrogenase activity in the rice-soil system and the possible contribution of epiphytic cyanobacteria on rice plants and other macrophytes to this activity were studied in two locations in the rice fields of Valencia, Spain, in two consecutive crop seasons. The largest proportion of photodependent N 2 fixation was associated with the macrophyte Chara vulgaris in both years and at both locations. The nitrogen fixation rate associated with Chara always represented more than 45% of the global nitrogenase activity measured in the rice field. The estimated average N 2 fixation rate associated with Chara was 27.53 kg of N ha ؊1 crop ؊1 . The mean estimated N 2 fixation rates for the other parts of the system for all sampling periods were as follows: soil, 4.07 kg of N ha ؊1 crop ؊1 ; submerged parts of rice plants, 3.93 kg of N ha ؊1 crop ؊1 ; and roots, 0.28 kg of N ha ؊1 crop ؊1 . Micrographic studies revealed the presence of epiphytic cyanobacteria on the surface of Chara. Three-dimensional reconstructions by confocal scanning laser microscopy revealed no cyanobacterial cells inside the Chara structures. Quantification of epiphytic cyanobacteria by image analysis revealed that cyanobacteria were more abundant in nodes than in internodes (on average, cyanobacteria covered 8.4% ؎ 4.4% and 6.2% ؎ 5.0% of the surface area in the nodes and internodes, respectively). Epiphytic cyanobacteria were also quantified by using a fluorometer. This made it possible to discriminate which algal groups were the source of chlorophyll a. Chlorophyll a measurements confirmed that cyanobacteria were more abundant in nodes than in internodes (on average, the chlorophyll a concentrations were 17.2 ؎ 28.0 and 4.0 ؎ 3.8 g mg [dry weight] of Chara ؊1 in the nodes and internodes, respectively). These results indicate that this macrophyte, which is usually considered a weed in the context of rice cultivation, may help maintain soil N fertility in the rice field ecosystem.Rice fields are one of the most extensive freshwater ecosystems on Earth, covering about 150 ϫ 10 6 ha. In spite of the widespread dominance of rice plants, a conspicuous photosynthetic aquatic biomass composed of cyanobacteria, planktonic, filamentous, and macrophytic algae, and vascular macrophytes develops during different phases of rice growth and competes with rice for nutrients and light (23). Nitrogen is a major factor in rice production. However, the efficiency of N fertilizer is one of the lowest efficiencies of all plant nutrients due to large N losses from flooded soils (7). Native soil nitrogen is the main N source for rice, accounting for more than 50% of the N in the rice plant (9, 10, 17), and so long-term sustainability of rice cultivation depends on the use and effective management of internal resources that maintain soil N fertility. The soil N pool is believed to be maintained by biological nitrogen fixation (17,25). In fact, biological N 2 fixation has allowed a stable and moderate yield to be maintained in traditional low-input rice cul...

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“…Our recent studies has shown that even the cyanobacteria mainly Nostoc and Anabaena were found to be capable of forming associations with wheat roots grown in liquid culture [22]. In recent years, evidence is accumulating on the production of signals by the cyanobionts, which affects the gene expression of the host plants, and thereby brings about qualitative and quantitative changes in the soil micro flora in the rhizosphere [31,32,76].…”

Section: Distribution Of Cyanobacteriamentioning

confidence: 99%

“…Most of the works related to cyanobacterial biofertilizers have been in relation to rice crop, and few reports are available on epiphytic growth of Gleotrichia pisum on the aquatic roots/stem of deep water rice [76]. Cocultivation of wheat with cyanobacteria is known to enhance root dry weight and chlorophyll [35].…”

Section: Heterotrophic Contributionsmentioning

confidence: 99%

Developments in Cyanobacterial Biofertilizer

Kaushik¹

2014

Proceedings of the Indian National Science Academy

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Rice is the world's most important food crop as more than 40% of the world's population depends on rice as a major source of calories. Rice yield in India is about 1990 kg/ha against a maximum of 3346 kg/ha in Punjab. Though the rice y i e l d s i n P u n j a b i s h i g h e s t i n t h e c o u n t r y, i t i s q u i t e l o w c o m p a r e d t o C h i n a ( 5 8 0 7 k g / h a ) . S u c h d i v e r s i t y i n y i e l d s i s d u e to insufficient use of fertilizer nitrogen. Nitrogen is present as elemental nitrogen in the atmosphere and constitutes more than 79 per cent of total gases. However, crop plants cannot utilize nitrogen in elemental form. On global level, out of 180 m i l l i o n t o n n e s o f n i t r o g e n a d d e d a n n u a l l y o n t h e e a r t h 's s u r f a c e , 2 / 3 i s t h r o u g h b i o l o g i c a l p r o c e s s e s , l a r g e l y m i c r o b i a l activities. Cyanobacteria colonize rice fields and provide biologically fixed nitrogen to the rice crop to the extent of 25-30 kg nitrogen per hectare. In India, on an average, cyanobacteria accounts to about 33% of total algal flora of Indian rice fi el d so i l s [ 6 6 ] , wh ereas i n so me o f t h e so u t h ern an d east ern st at es t h i s reach es u p t o 5 0 %. Vi rt u al l y al l t h e d o mi n an t cyanobacteria in rice fields are nitrogen fixing. Ap a r t fr o m i n c r e a s e i n yi e l d a n d s a v i n g o f fe r t i l i z e r n i t r o g e n , c ya n o b a c t e r i a l i n o c u l a t i o n i mp r o v e s t h e p h ys i c o -c h e mi c a lproperties of soil, gradual build-up of residual soil nitrogen and carbon, improvement in soil pH and electrical conductivity. The grain quality in terms of protein content was improved. Our recent studies have shown that the cyanobacteria (Nostoc a n d Anabaena) were cap ab le o f formi ng associati ons wit h wh eat ro ots gro wn i n li qu id cu lt ure. P ro babl y, su ch cyano bact eria contribute nitrogen and growth promoting substances to plants in the rhizosphere.

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Ecology of deepwater rice-fields in Bangladesh 3. Associated algae and macrophytes

Cited by 41 publications

References 7 publications

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

Epiphytic Cyanobacteria onChara vulgarisAre the Main Contributors to N₂Fixation in Rice Fields

Developments in Cyanobacterial Biofertilizer

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Ecology of deepwater rice-fields in Bangladesh 3. Associated algae and macrophytes

Cited by 41 publications

References 7 publications

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

Cyanobacterial diversity in the rhizosphere of rice and its ecological significance

Epiphytic Cyanobacteria onChara vulgarisAre the Main Contributors to N2Fixation in Rice Fields

Developments in Cyanobacterial Biofertilizer

Contact Info

Product

Resources

About

Epiphytic Cyanobacteria onChara vulgarisAre the Main Contributors to N₂Fixation in Rice Fields