PHYSIOLOGICAL ROLE OF SILICON NUTRITION IN THE REPRODUCTIVE STAGE ON YIELD OF HYDROPONIC RICE (Oryza sativa L.)
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Date
2023-11-29
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Acharya N G Ranga Agricultural University
Abstract
A net house experiment entitled “Physiological role of silicon nutrition in the reproductive stage on yield of hydroponic rice (Oryza sativa L.).” was carried out at net house of Department of Crop Physiology Agricultural College, Bapatla during 2019- 2020 to study the effect of silicon nutrition on mobility of photosynthetic assimilates, leaf photosynthetic parameters, yield attributes and silicon uptake by rice at different time intervals during reproductive stage. Cv. BPT-5204 was used for the investigation. The experiment was laid out in three factorial completely randomized design with nineteen treatments viz., control (No silicon), foliar application of silicon with 50 mM, 100 mM, 150 mM concentration and through root application with 1.5 mM, 2.0 mM and 2.5 mM concentration of silicon. The treatments were applied at P.I (P1), 10 d. after P.I (P2) and 20 d. after P.I (P3). Observations were noted after 10 days of silicon application on physiological and biochemical parameters. Data on yield and yield attributes were recorded at harvest.
From the above investigation, at all the three sampling stages silicon application increased the photosynthetic rate, stomatal conductance and SPAD value of rice leaves either through foliar or root application. But transpiration rate of rice leaves was decreased with silicon application either through root or foliar modes and this decrease was more through root mode with 2.0 mM concentration of silicon.
Silicon application through root system with 2.0 mM concentration of sodium silicate at three different times during reproductive stage increased the total sugar and silicon contents of rice leaf and culm. Foliar application with 50 mM concentration of sodium silicate increased the parameters like starch content and starch phosphorylase activity of rice leaf and culm. The increasing effect of biochemical parameters of leaf and culm were reached to maximum at heading stage and then decreased, irrespective of time and form of silicon application.
During all the three different sampling times, the uptake of silicon by the rice plant from nutrient solution was increased with the application of silicon @2.0 mM concentration among 1.5 mM and 2.5 mM concentration of silicon.
Grain constituents like total sugar and silicon contents were increased with root application of silicon. But foliar application of silicon, increased the grain parameters like starch content and starch phosphorylase activity and this increasing effect was more at 10 d. after P.I with silicon application than at P.I and 20 d. after P.I stages, either through soil or foliar modes.
Yield and yield attributing characters like panicle length, filled spikelet percentage, test weight, harvest index and grain yield per panicle were increased by root application of silicon, while spikelet length, number of primary and secondary branches of panicle were increased by foliar application of silicon and this increase was more at 10 d. after P.I than other times of application, irrespective of mode of silicon nutrition.