M. Banerjee,* A. Sharma and T. Thomas. This study points to the utility of Aulosira fertilissima and algal biomass of the Upper and Lower lake of Bhopal as.
World Journal of Microbiology & Biotechnology 13, 595±596
Short Communication: Potential use of lake cyanobacterial biomass as fertilizer for the cultivation of food crops M. Banerjee,* A. Sharma and T. Thomas This study points to the utility of Aulosira fertilissima and algal biomass of the Upper and Lower lake of Bhopal as a cheap and effective green manure for rice and mustard. Key words: Algal biomass, Aulosira yield, Brassica campestris, Oryza sativa. The escalating cost of synthetic nitrogenous fertilizers has made it imperative to ®nd alternate sources of N2. Biological N2-®xation offers an economically attractive means to combat the ill-effects of chemical fertilizers and serve as an alternative source of N2 for crops. Most algalization experiments so far conducted have been on rice (Oryza sativa) with little information on other crops (Morries et al. 1985; Roger & Ladha 1990). In Indian paddy ®elds Aulosira fertilissima warrants particular attention as it is one of the strongest N2-®xers present in that niche, and contributes greatly in increasing soil N2-content along with other strains like Anabaena, Nostoc and Gloeotricha. The present work was an attempt to study the potential of algal biomass of lakes consisting mostly of cyanobacteria and two other potential N2-®xers to act as a source of green manure for rice (Oryza sativa) and mustard (Brassica campestris) cultivation.
Materials and Methods Anabaena ¯os aquae and Aulosira fertilissima were collected from the Upper lake of Bhopal and IARI New Delhi respectively. These cultures grew well in CHU-10 medium (as modi®ed by Gerloff et al. 1959). Algal biomass used in the present study for fertilization of the plants speci®ed was collected from the Upper lake and Lower lake of Bhopal. Statistical Analysis Correlation coef®cient (r) was calculated for different treatments and its effect on root length, number of grains and dry weight of grains by the equation:
RXY ÿ
RX
RY r q
NRX2 ÿ
RX2 ÿ
NRY2 ÿ
RY2
The authors are with the Algal Research Unit, Department of Bioscience, Barkatullah University, Bhopal-462026, India.*Corresponding author.
where N is the number of observations, X is the different treatments given to the rice and mustard plants, and Y is the root length/number of grains/dry weight of grains. Pot and Field Experiments The ®eld and pot experiments were conducted during the winter season using the Basmati variety of rice (pot) and Brassica campestris (®eld). Triplicate pots and plots were used for each experiment in which (1) was the control (10% urea), (2) was treated with Anabaena, (3) was treated with Aulosira, (4) was treated with biomass from the Upper lake and (5) with algal biomass from the Lower lake. Plant height was measured from the lowest node at the base of the plant to the end of the fully unfurled top leaf of the main shoot for both crops. After ¯owering the upper limit ®xed for this measurement was the base of the ear for rice and base of ¯ower initiation for mustard. All the parameters studied were recorded at the initial stage of growth and at maturity. Treatments Treatments were started as soon as the seedling reached a height of 3.5 cm. For algal treatments exponentially grown laboratory cultured cells of Anabaena ¯os aquae and Aulosira fertilissima and algal biomass harvested from the lakes (Lower and Upper) were taken. Fresh weight (10 g) of each of the four sets mentioned above were added in different plots in three splits: basal, tillering and panicle/¯ower initiation. Grain samples after harvest from each treatment were dried in the sun and cleaned manually for dry weight and protein analysis.
Results and Discussion For rice, the maximum increase in root and shoot length and root/shoot ratio was observed with Aulosira followed by algal biomass from the Upper lake. The effect of the different treatment on root length showed a positive correlation coef®cient of r = 0.920, d.f. = 4, p > 0.01 for Aulosira, r = 0.952, d.f. = 4, p > 0.01 for algal biomass from Upper lake and r = 0.973, d.f. = 4, p > 0.01 for Anabaena. Similarly positive correlation coef®cients were obtained for shoot length and root/shoot ratio. Maximum length of panicle was observed with algal biomass from the Upper lake followed by Aulosira (Table 1). Maximum enhancement in grain number and dry weight
ã 1997 Rapid Science Publishers World Journal of Microbiology & Biotechnology, Vol 13, 1997
595
M. Banerjee et al. Table 1. Effect of algalization on the root, shoot, panicle/pod length and root shoot ratio of rice and mustard plants receiving different treatments. Average length of roots (cm) Treatment 1 2 3 4 5
Control Anabaena Aulosira Upper lake biomass Lower lake biomass
Rice
Mustard
6.7* 10.07 (50)F 16.75 (150) 12.2 (82) 8.2 (22)
4.5 10.5 13.5 8.5 6.5
(133) (200) (131) (44)
Average length of shoots (cm) Rice 37.5 44.25 54.75 52.25 43.75
(18) (46) (40) (22)
Average length of panicles/pods (cm)
Fold increase root/shoot ratio
Mustard
Rice
Mustard
Rice
Mustard
27.5 35 (27) 46 (67) 46.5 (69) 29 (5)
9.07 13.32 (46) 18.87 (108) 19.54 (115) 11.15 (22)
2.7 4 (48) 5.5 (103) 4 (48) 2.7 (±)
1.27G 1.71 1.30 1.00
1.87 1.81 1.10 1.30
* Mean of four plants from each plot/pot; F values in parentheses are percentage increases over controls; G fold increase. Table 2. Effect of algalization on number of grains, dry weight and protein content of grains of rice and mustard plants receiving different treatments. Number of grains Treatments 1 2 3 4 5
Control Anabaena Aulosira Upper lake biomass Lower lake biomass
Rice
Mustard
33.5* 45.5 (1.35)F 67.25 (2.0) 69.50 (2.0) 42.0 (1.2)
36.3 91.0 (2.5) 200.00 (5.5) 242.00 (6.6) 40.0 (1.1)
Dry weight of grains (g) Rice 3.0 6.3 7.1 7.4 5.7
(2.1) (2.3) (2.4) (1.3)
Mustard 0.2 0.6 1.0 1.1 0.3
(3) (5) (5.3) (1.5)
Protein content of grains (lg/g dry weight) Rice
Mustard
278 300 (1.3) 371 (1.3) 373 (1.3) 245 ())
226 258 (1.0) 278 (1.2) 264 (1.1) 200 ())
* Mean of four plants from each plot/pot. F Values in parentheses are fold increases over controls.
was observed with Upper lake biomass followed by Aulosira. Protein content of grains was found to increase with addition of Upper lake biomass, Aulosira and Anabaena. For mustard the maximum increase in root length was observed with Aulosira followed by Anabaena and Upper lake biomass. The effect of different treatments on root length showed a positive correlation coef®cient of r = 0.933, d.f. = 4, p > 0.01 for Aulosira r = 0.927, d.f. = 4, p > 0.01 for Anabaena and r = 0.969, d.f. = 4, p > 0.01 for algal biomass from the Upper lake. Root/shoot ratio showed the maximum increase with Anabaena followed by Aulosira. For grain number and dry weight, the maximum increase was obtained with Upper lake biomass followed by Aulosira. Protein content was found to be maximum with Aulosira, Upper lake biomass and Anabaena (Table 2). The studies indicate that algalization with different cyanobacteria produces signi®cant improvement in growth and ®nal grain yield of both crops. This increase can be attributed to the increase in soil N2 or the production of plant growth substances as reported for various cyanobacteria (Gupta & Shukla 1967; Banerjee unpublished work). Alternatively, this enhancement could also be due to the great availability of assimilated nitrogen by the cyanobacterial N2-®xation.
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World Journal of Microbiology & Biotechnology, Vol 13, 1997
Thus harvesting of algal biomass technology, if put to use, could reduce our dependence on chemical fertilizer considerably.
Acknowledgement We are thankful to the Head, Department of Bioscience, for providing laboratory facilities.
References Banerjee, M. & Sharma, A. 1994 Agronomic signi®cance of utilizing algal biomass from lakes as green manure for cultivation of Triticum vulgare. Cienti®ca, Sao Paulo 22(2), 195±203. Gerloff, G.L., Fitzgerland, G.P. & Skoog, F. 1959 The isolation, puri®cation and culture of blue-green algae. American Journal of Botany 37, 216±218. Gupta, A.B. & Shukla, A.C. 1969 Effects of algal extracts of Phormidium species on growth and development of rice seedlings. Hydrobiologia 34, 77±84. Morries, R.A., Furoc, R.E., Rajbhandari, N.K., Marqueses, E.P. & Dizon, M.A. 1985 Rice response to waterlog tolerant green manures. Agronomic Journal 81, 803±809. Roger, P.A. & Ladha, J.K. 1990 Estimation of biological N2 ®xation and its contribution to nitrogen balance in wetland rice ®elds. In Proceeding of 14th International Congress of Soil Sciences, Kyoto, Japan pp. 128±133.
(Received in revised form 4 October 1996; accepted 8 October 1996)
