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Papers by Rizvi Jamaldeen

Rice is the staple food crop of Sri Lanka and the eastern province alone contributes to more than... more Rice is the staple food crop of Sri Lanka and the eastern province alone contributes to more than 21% of the total production of the country. Excessive amounts of chemical fertilizers are used to obtain a higher yield which has been noted to contribute to deteriorate soil microbial community. This leads to poor quality soil resulting in poor crop growth. Use of microbial biofertilizers for rice has gained momentum as a measure of replenishing the depleted soil microbiome, and to restore the beneficial processes. Amongst microbial biofertilizers, biofilmed biofertilizers (BFBFs) have been found to act as microbial ameliorators in deteriorated soil, contributing to better plant growth and higher yield. A field trial using a BFBF (comprising of non-native microorganisms) and rice variety BG 357 was conducted in 2011 Yala season (May — August) at Sammanthurai Agriculture Research Station to assess the potential of the BFBF for rice in the Eastern province. The use of BFBF increased seed...

Diazotrophs are investigated to be used in bio fertiliser formulations for wetland rice with the ... more Diazotrophs are investigated to be used in bio fertiliser formulations for wetland rice with the objective of improving production with little environmental impact. Strategies to improve the contribution of associative dinitrogen fixation to the host plant are necessary in this regard. The most common limiting factor for diazotroph activity in soil is the availability of sufficient carbon substrates for the inoculum. The contribution of nitrogen by Azospirillum irakense KBC1 to rice variety BG 94-1 when supplemented with rice straw as a source of C was studied under controlled conditions using N labelled soil. Combined application of Azospirillum and straw contributed significantly than the straw alone or mineral fertilizer alone or straw + mineral fertilizer combined treatments in terms of grain yield or grain N-content. Inoculum benefited more from straw over native heterotrophs. Provision of C substrates for the inoculum apparently is important in improving BNF over inoculation a...

Biofilms are consortia formed by different microbes of which the members are physically and metab... more Biofilms are consortia formed by different microbes of which the members are physically and metabolically interdependent and the consortia harbor properties distinct from those of their single components and thus have various applications including improved agricultural productivity. Beneficial biofilms can be developed in vitro and be used as biofertilizers called biofilmedbiofertilizers (BFBFs).Objective of this study was to formulate an effective BFBF formulation for rice. Seven bacterial species isolated from two different paddy soils (coastal and inland) were grown separately in association with a fungus. Four of these two-membered cultures selected as potential biofilm formulations based on forming intimate association, plant growth substance production and N rfixing ability were tested for the impact on rice seed germination and seedling growth. The percentage seed germination and seedling vigour index of seeds treated with the above four biofilm formulations were significant...

Inoculation with plant growth promoting rhizobacteria (PGPR) are considered as a solution to the ... more Inoculation with plant growth promoting rhizobacteria (PGPR) are considered as a solution to the environmental and economic problems of using chemical fertilizers and pesticides. Inoculation with consortia of several bacterial strains is suggested as an alternative to inoculation with single species and mixed species introduced strains. Rice variety BG 250 grown in modified Yoshida rice nutrient solution was inoculated with suspensions of 3 different paddy soils separately with the aim of selecting a soil with effective microbial consortia. Inoculations did not affect any vegetative or reproductive parameter 3 or 14 weeks after transplanting despite the non-competitive conducive environment prevailing in the pots.The major reason could be presence of nutrients particularly nitrogen in sufficient quantities since this suppresses the effect of microbes. Further studies are needed with inoculation under low levels of nitrogen preferably with different rice varieties and different soils...

The haphazard application of synthetic chemicals in agriculture has led to loss of beneficial mic... more The haphazard application of synthetic chemicals in agriculture has led to loss of beneficial microbial communities leading to deteriorating soil productivity and environmental quality. Application of Plant growth promoting rhizobacteria (PGPRs) is widely tested world over to overcome this problem and increasing productivity in different plant species has been demonstrated. Use of biofilmed biofertilizers (BFBFs) is speculated to be more beneficial than the use of monoculture PGPRs and it has been found that use of in vitro produced BFBFs could reduce the use of recommended chemical fertilizers by about 50% in certain crops which would be of great importance in terms of environmental health and economy. The aim of this study was to test the effect of an in vitro formulated BFBF on the growth and yield of rice in soils from which the component bacterium and fungus of BFBF were isolated. Rice variety BG 357 was grown in pots in a green house, in two paddy soils with different salinity...

6th International Symposium 2016 on “Multidisciplinary Research for Sustainable Development in the Information Era,” pp 423-430., 2016

Allelopathy can be defined as a process involving secondary metabolites produced by plants, micro... more Allelopathy can be defined as a process involving secondary metabolites produced by plants, micro-organisms, viruses, and fungi that influence the growth and development of agricultural and biological systems (excluding animals), including positive and negative effects. The present study was aimed at evaluating the allelopathic effects of straw of two rice varieties (B.G. 352 and B.G. 357) and seven plant leaf extracts namely Calotropis procera, Cassia fistula, Cymborpogon nardus, Eucalyptus sp., Lantana camara, Leucas aspera and Pinus sp. Four concentrations (05%, 10%, 15% and 20% w/v) were tested for allelopathy {Seed Germination Percentage (SGP) and Seedling Vigor Index (SVI)} on a weedy rice variety and four cultivated rice varieties namely AT 362 (Rosa Kekulu), BG 39/16, Samba 365/3 and Sudu 400/2. The data obtained were analysed employing general linear model ANOVA test using Minitab software 16.1.1 to detect the significance of differences at 5% probability level. All tested ...

Heavy metals induce multiple organ damage even at low levels of exposure. They are also classifie... more Heavy metals induce multiple organ damage even at low levels of exposure. They are also classified as known or probable human carcinogens in the United States. Man is exposed to environmental heavy metals mainly through the soil crop system. Rice is one of the major sources of human intake of Cd and Pb. Ampara district is an area of intensive paddy cultivation with high input of chemical fertilizers and agrochemicals, which are anthropogenic sources of heavy metals. This preliminary study was conducted to determine whether the heavy metal content of paddy soils and rice in Ampara district is at safe levels. Random samples in triplicates of grains of Oryza sativa L. (variety AT 362) and paddy soil in 2016/17 ‘Maha’ season from three different sites 1. Addalachenai, 2. Sammanthurai and 3. Urani were collected the day prior to harvest. Soil samples and dehusked paddy grains were tested using ICP-OES (ICAP Thermo, USA) for sixteen heavy metals. Data of different sites were compared usin...

Various plant traits are used to determine plant growth and development. Variation in plant trait... more Various plant traits are used to determine plant growth and development. Variation in plant traits and there associations within and among species, is associated with many important ecological processes at a range of scales. These traits could be used in restoration ecology to determine the competition and performance of introduced plant species. Leaf traits are among the widely used. This study was performed to compare the different leaf traits of three dry zone tree species i.e. Berrya cordifolia, Ficus racemosa and Terminalia arjuna to be used as performance indicators in restoration. Leaf parameters (leaf number, area and dry weight) and root and shoot dry weights were recorded of eight month old seedlings, in triplicates per species, grown under greenhouse conditions and required traits i.e. LMA (leaf mass per unit area), SLA (specific leaf area – leaf area per unit leaf mass) and LMF (Leaf Mass Fraction, fraction of plant biomass allocated to leaves) were derived. Data were an...

Five new improved rice varieties released by Rice Research and Development Institute, Bathalagoda... more Five new improved rice varieties released by Rice Research and Development Institute, Bathalagoda were screened against salt tolerance for seed germination and early seedling growth using five different salinity levels (0, 4, 8, 12, and 16 dS/m). Measurements were taken for root length, shoot length, fresh weight of seedlings, dry weight of seedlings, germination energy, speed of germination and final germination percentage. All the tested variables, except dry weight of seedlings, decreased with increasing salinity and had a significant difference (p<0.05) between salinity levels. Osmotic stress due to increasing salinity and toxic effect due to high sodium ion concentration interfere water absorption by plants and affect physiological activities in seeds and seed germination. Among the rice varieties used, Bg 357 rice variety had a higher root length, shoot length, fresh weight of seedlings, germination energy, speed of germination and final germination percentage and was consi...

By 2050, 50% of the world’s arable lands are estimated to be affected by salinity leading to a ri... more By 2050, 50% of the world’s arable lands are estimated to be affected by salinity leading to a risk in food production. Poor seed germination due to salinity is a major problem in the olericulture sector of low country dry zone in Sri Lanka. This preliminary study was aimed to evaluate the effect of salinity on seed germination of five locally bred vegetable crops commonly cultivated in low country dry zone of Sri Lanka: Abelmoschus esculentus (Okra, variety Beeralu, Malvaceae), Cucurbita maxima (Pumpkin, variety ANK, Cucurbitaceae), Zea mays (Sweet corn, Thai compositae hybrid, Poaceae), Vigna unguiculata (Yard long bean, variety Gannoruwa hybrid Mae, Fabaceae) and Solanum melongena (Eggplant, variety Vihara hybrid, Solanaceae). Ten seeds per petri dish (double layer tissue bedded) with three replicates per salinity level were germinated for five levels of salinity (electric conductivities 0.0 dS/m, 2.5 dS/m, 5.0 dS/m, 7.5 dS/m and 10 ds/m.). The imbibition rate, final germination ...

Rice is the staple food crop of Sri Lanka and the eastern province alone contributes to more than... more Rice is the staple food crop of Sri Lanka and the eastern province alone contributes to more than 21% of the total production of the country. Excessive amounts of chemical fertilizers are used to obtain a higher yield which has been noted to contribute to deteriorate soil microbial community. This leads to poor quality soil resulting in poor crop growth. Use of microbial biofertilizers for rice has gained momentum as a measure of replenishing the depleted soil microbiome, and to restore the beneficial processes. Amongst microbial biofertilizers, biofilmed biofertilizers (BFBFs) have been found to act as microbial ameliorators in deteriorated soil, contributing to better plant growth and higher yield. A field trial using a BFBF (comprising of non-native microorganisms) and rice variety BG 357 was conducted in 2011 Yala season (May — August) at Sammanthurai Agriculture Research Station to assess the potential of the BFBF for rice in the Eastern province. The use of BFBF increased seed...

Diazotrophs are investigated to be used in bio fertiliser formulations for wetland rice with the ... more Diazotrophs are investigated to be used in bio fertiliser formulations for wetland rice with the objective of improving production with little environmental impact. Strategies to improve the contribution of associative dinitrogen fixation to the host plant are necessary in this regard. The most common limiting factor for diazotroph activity in soil is the availability of sufficient carbon substrates for the inoculum. The contribution of nitrogen by Azospirillum irakense KBC1 to rice variety BG 94-1 when supplemented with rice straw as a source of C was studied under controlled conditions using N labelled soil. Combined application of Azospirillum and straw contributed significantly than the straw alone or mineral fertilizer alone or straw + mineral fertilizer combined treatments in terms of grain yield or grain N-content. Inoculum benefited more from straw over native heterotrophs. Provision of C substrates for the inoculum apparently is important in improving BNF over inoculation a...

Biofilms are consortia formed by different microbes of which the members are physically and metab... more Biofilms are consortia formed by different microbes of which the members are physically and metabolically interdependent and the consortia harbor properties distinct from those of their single components and thus have various applications including improved agricultural productivity. Beneficial biofilms can be developed in vitro and be used as biofertilizers called biofilmedbiofertilizers (BFBFs).Objective of this study was to formulate an effective BFBF formulation for rice. Seven bacterial species isolated from two different paddy soils (coastal and inland) were grown separately in association with a fungus. Four of these two-membered cultures selected as potential biofilm formulations based on forming intimate association, plant growth substance production and N rfixing ability were tested for the impact on rice seed germination and seedling growth. The percentage seed germination and seedling vigour index of seeds treated with the above four biofilm formulations were significant...

Inoculation with plant growth promoting rhizobacteria (PGPR) are considered as a solution to the ... more Inoculation with plant growth promoting rhizobacteria (PGPR) are considered as a solution to the environmental and economic problems of using chemical fertilizers and pesticides. Inoculation with consortia of several bacterial strains is suggested as an alternative to inoculation with single species and mixed species introduced strains. Rice variety BG 250 grown in modified Yoshida rice nutrient solution was inoculated with suspensions of 3 different paddy soils separately with the aim of selecting a soil with effective microbial consortia. Inoculations did not affect any vegetative or reproductive parameter 3 or 14 weeks after transplanting despite the non-competitive conducive environment prevailing in the pots.The major reason could be presence of nutrients particularly nitrogen in sufficient quantities since this suppresses the effect of microbes. Further studies are needed with inoculation under low levels of nitrogen preferably with different rice varieties and different soils...

The haphazard application of synthetic chemicals in agriculture has led to loss of beneficial mic... more The haphazard application of synthetic chemicals in agriculture has led to loss of beneficial microbial communities leading to deteriorating soil productivity and environmental quality. Application of Plant growth promoting rhizobacteria (PGPRs) is widely tested world over to overcome this problem and increasing productivity in different plant species has been demonstrated. Use of biofilmed biofertilizers (BFBFs) is speculated to be more beneficial than the use of monoculture PGPRs and it has been found that use of in vitro produced BFBFs could reduce the use of recommended chemical fertilizers by about 50% in certain crops which would be of great importance in terms of environmental health and economy. The aim of this study was to test the effect of an in vitro formulated BFBF on the growth and yield of rice in soils from which the component bacterium and fungus of BFBF were isolated. Rice variety BG 357 was grown in pots in a green house, in two paddy soils with different salinity...

6th International Symposium 2016 on “Multidisciplinary Research for Sustainable Development in the Information Era,” pp 423-430., 2016

Allelopathy can be defined as a process involving secondary metabolites produced by plants, micro... more Allelopathy can be defined as a process involving secondary metabolites produced by plants, micro-organisms, viruses, and fungi that influence the growth and development of agricultural and biological systems (excluding animals), including positive and negative effects. The present study was aimed at evaluating the allelopathic effects of straw of two rice varieties (B.G. 352 and B.G. 357) and seven plant leaf extracts namely Calotropis procera, Cassia fistula, Cymborpogon nardus, Eucalyptus sp., Lantana camara, Leucas aspera and Pinus sp. Four concentrations (05%, 10%, 15% and 20% w/v) were tested for allelopathy {Seed Germination Percentage (SGP) and Seedling Vigor Index (SVI)} on a weedy rice variety and four cultivated rice varieties namely AT 362 (Rosa Kekulu), BG 39/16, Samba 365/3 and Sudu 400/2. The data obtained were analysed employing general linear model ANOVA test using Minitab software 16.1.1 to detect the significance of differences at 5% probability level. All tested ...

Heavy metals induce multiple organ damage even at low levels of exposure. They are also classifie... more Heavy metals induce multiple organ damage even at low levels of exposure. They are also classified as known or probable human carcinogens in the United States. Man is exposed to environmental heavy metals mainly through the soil crop system. Rice is one of the major sources of human intake of Cd and Pb. Ampara district is an area of intensive paddy cultivation with high input of chemical fertilizers and agrochemicals, which are anthropogenic sources of heavy metals. This preliminary study was conducted to determine whether the heavy metal content of paddy soils and rice in Ampara district is at safe levels. Random samples in triplicates of grains of Oryza sativa L. (variety AT 362) and paddy soil in 2016/17 ‘Maha’ season from three different sites 1. Addalachenai, 2. Sammanthurai and 3. Urani were collected the day prior to harvest. Soil samples and dehusked paddy grains were tested using ICP-OES (ICAP Thermo, USA) for sixteen heavy metals. Data of different sites were compared usin...

Various plant traits are used to determine plant growth and development. Variation in plant trait... more Various plant traits are used to determine plant growth and development. Variation in plant traits and there associations within and among species, is associated with many important ecological processes at a range of scales. These traits could be used in restoration ecology to determine the competition and performance of introduced plant species. Leaf traits are among the widely used. This study was performed to compare the different leaf traits of three dry zone tree species i.e. Berrya cordifolia, Ficus racemosa and Terminalia arjuna to be used as performance indicators in restoration. Leaf parameters (leaf number, area and dry weight) and root and shoot dry weights were recorded of eight month old seedlings, in triplicates per species, grown under greenhouse conditions and required traits i.e. LMA (leaf mass per unit area), SLA (specific leaf area – leaf area per unit leaf mass) and LMF (Leaf Mass Fraction, fraction of plant biomass allocated to leaves) were derived. Data were an...

Five new improved rice varieties released by Rice Research and Development Institute, Bathalagoda... more Five new improved rice varieties released by Rice Research and Development Institute, Bathalagoda were screened against salt tolerance for seed germination and early seedling growth using five different salinity levels (0, 4, 8, 12, and 16 dS/m). Measurements were taken for root length, shoot length, fresh weight of seedlings, dry weight of seedlings, germination energy, speed of germination and final germination percentage. All the tested variables, except dry weight of seedlings, decreased with increasing salinity and had a significant difference (p<0.05) between salinity levels. Osmotic stress due to increasing salinity and toxic effect due to high sodium ion concentration interfere water absorption by plants and affect physiological activities in seeds and seed germination. Among the rice varieties used, Bg 357 rice variety had a higher root length, shoot length, fresh weight of seedlings, germination energy, speed of germination and final germination percentage and was consi...

By 2050, 50% of the world’s arable lands are estimated to be affected by salinity leading to a ri... more By 2050, 50% of the world’s arable lands are estimated to be affected by salinity leading to a risk in food production. Poor seed germination due to salinity is a major problem in the olericulture sector of low country dry zone in Sri Lanka. This preliminary study was aimed to evaluate the effect of salinity on seed germination of five locally bred vegetable crops commonly cultivated in low country dry zone of Sri Lanka: Abelmoschus esculentus (Okra, variety Beeralu, Malvaceae), Cucurbita maxima (Pumpkin, variety ANK, Cucurbitaceae), Zea mays (Sweet corn, Thai compositae hybrid, Poaceae), Vigna unguiculata (Yard long bean, variety Gannoruwa hybrid Mae, Fabaceae) and Solanum melongena (Eggplant, variety Vihara hybrid, Solanaceae). Ten seeds per petri dish (double layer tissue bedded) with three replicates per salinity level were germinated for five levels of salinity (electric conductivities 0.0 dS/m, 2.5 dS/m, 5.0 dS/m, 7.5 dS/m and 10 ds/m.). The imbibition rate, final germination ...