Effect of silicon on the growth of rice plant at different growth stages

Rice plants (Oryza sativa L. cv. Akebono) were cultured in Kimura B solution. The effect of silicon on plant growth and the characteristics of the uptake and distribution of silicon at different growth stages were studied from both aspects: the addition and removal of silicon during the vegetative, reproductive and ripening stages.

When silicon was removed during the reproductive stage, the dry weights of straw (stem+leaf blade) and grain decreased by 20 and 50% respectively, compared with those of the plants cultured in the solution with silicon throughout the growth period. Conversely, when silicon was added during the reproductive stage, the dry weights of straw and grain increased by 243 and 30%, respectively, over those of the plants cultured in a solution devoid of silicon throughout the growth period. The effect of silicon on the dry weights of straw and grain was small when silicon was either added or removed during the vegetative and ripening stages. [1]

Effect of brassinosteroids on salinity stress induced inhibition of seed germination and seedling growth of rice (Oryza sativa L.)

The effect of 24-epibrassinolide and 28-homobrassinolide on the inhibitionof germination and seedling growth of rice (Oryza sativa) induced bysalinity stress was studied. Brassinosteroids were found to reverse theinhibitory effect on germination and seedling growth. The activation ofseedling growth by brassinosteroids under salinity stress was associatedwith enhanced levels of nucleic acids and soluble proteins. [2]

Cell wall peroxidase activity, hydrogen peroxide level and NaCl-inhibited root growth of rice seedlings

The changes in cell-wall peroxidase (POD) activity and H2O2 level in roots of NaCl-stressed rice seedlings and their correlation with root growth were investigated. Increasing concentrations of NaCl from 50 to 150 mM progressively reduced root growth and increased ionically bound cell-wall POD activity. NaCl had no effect on covalently bound cell-wall POD activities. The reduction of root growth by NaCl is closely correlated with the increase in H2O2 level. Exogenous H2O2 was found to inhibit root growth of rice seedlings. Since ammonium and proline accumulation are associated with root growth inhibition caused by NaCl, we determined the effects of NH4Cl or proline on root growth, cell-wall POD activity and H2O2level in roots. [3]

Assessing the Effects of Water Management Regimes and Rice Residue on Growth and Yield of Rice in Uganda

Aim: This study was conducted to assess the influence of different water and rice straw management practices and rice genotypes on growth and yield of rice in Uganda.

Study Design: Field experimental design was a Randomized Complete Block Design while the screen house study design was a Completely Randomized Design.

Place and Duration of Study: The study was conducted in the field at National Crops Resources Research Institute (NaCRRI) Namulonge and in the screen house at Kyambogo University during the period of February-July 2013.

Materials and Methods: Ten rice genotypes obtained from the cereals program at NaCRRI Namulonge were grown under different water management regimes, with and without rice straw incorporation both in the field and screen house. Water management regimes used were alternate wetting and drying (AWD), continuous flooding (CF) and continuous drying (CD).[4]

Characterization of Solid State Fermentation Culture Conditions for Growth and Mananase Production by Aspergillus niger USM F4 on Rice Husk in Tray System

Aim: The study evaluated various fermentation conditions for the production of mannanase.

Place and Duration of Study: Industrial Biotechnology Research Laboratory (IBRL), School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia between May 2009 and September 2010.

Methodology: Solid substrate fermentation was carried out in a shallow aluminum tray system (16 cm x 16 cm x 5 cm) for maximum mannanase production by Aspergillus niger USM F4 using rice husk as a substrate.

Results: The maximum mannanase activity of 119.91 U/g substrate was achieved on the 6 days of cultivation when the optimized physical parameters were used (substrate thickness of 1.6 cm or equivalent to 80 g of 0.75 mm rice husk, moisture content to substrate ratio of 1:1 (w/v), cultivation temperature at room temperature (28±2ºC), inoculum size of 6×106 spores/ml and in static condition (no mixing during the fermentation process). The results showed an increment of about 30.79% of mannanase activity after the optimization (119.91 U/g substrate) compared to before optimization (91.68 U/g substrate). [5]

Reference
[1] Ma, J., Nishimura, K. and Takahashi, E., 1989. Effect of silicon on the growth of rice plant at different growth stages. Soil Science and Plant Nutrition, 35(3), pp.347-356.

[2] Anuradha, S. and Rao, S.S.R., 2001. Effect of brassinosteroids on salinity stress induced inhibition of seed germination and seedling growth of rice (Oryza sativa L.). Plant Growth Regulation, 33(2), pp.151-153.

[3] Lin, C.C. and Kao, C.H., 2001. Cell wall peroxidase activity, hydrogen peroxide level and NaCl-inhibited root growth of rice seedlings. Plant and Soil, 230(1), pp.135-143.

[4] Awio, T., Bua, B. and Karungi, J. (2015) “Assessing the Effects of Water Management Regimes and Rice Residue on Growth and Yield of Rice in Uganda”, Journal of Experimental Agriculture International, 7(2), pp. 141-149. doi: 10.9734/AJEA/2015/15631.

[5] Ibrahim, D., Puspitaloka, H., Rahim, R. and Hong, L. (2012) “Characterization of Solid State Fermentation Culture Conditions for Growth and Mananase Production by Aspergillus niger USM F4 on Rice Husk in Tray System”, Biotechnology Journal International, 2(3), pp. 133-145. doi: 10.9734/BBJ/2012/1486.

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