Silicon Nutrition and Distribution in Plants of Different Thai Rice Varieties

Abstract

Rice grain yield benefits from silicon (Si) accumulation in sufficient concentration in the plant, but too much Si in the husk and straw can impede their usefulness as biofuel and animal feed. This study consisted of four experiments. The first experiment evaluated genotypic variation in Si distribution in different parts of the rice grain from farmers' fields in northern Thailand, parts of grain to compare tall plant type and semi-dwarf varieties. The result showed that there were significant differences among the rice varieties in Si concentration of their husk and straw, but without clear distinction between the tall and semi-dwarf plant type or between wetland and upland ecotype. The second experiment evaluated Si distribution in different plant parts among 29 Thai rice varieties, and found significant variation in Si concentration among different parts of the rice plant parts, with the husk Si almost twice the straw, and among the rice ecotypes. The third experiment determined the effect of Si fertilizer on Si distribution in a pot experiment on 3 rice varieties with and without of Si application. The fourth experiment evaluated the effect of different growing locations on Si concentration in different plant parts of the 3 rice varieties. These last 2 experiments showed that rice varieties responded differently to Si fertilizer and location in the Si concentration in their husk and straw. Grain yield was significantly correlated with the Si concentration in the husk but not in the straw. The genotype by environment and management interaction effect on Si concentration in the rice husk and straw together with their relationship to grain yield suggested that further investigation of the relationship between husk Si and grain yield. The underlying processes should make Si management for rice production more effective, for the potential energy to be recovered from the husk and straw as well as grain yield.

Silicon application improves caryopsis development and yield in rice

“…Previous studies have reported that the expression of Lsi6 level was affected by Si supply in maize leaves and it was upregulated by addition of Si 27 . The nearly 30% higher Si concentration in the husk of CNT1 than PTT1 when grown in the field 28 and the significantly higher Si concentration in the husk of CNT1 than PTT1 in +Si in the present study together suggest that Si may be a yield‐limiting factor in spikelet formation. It is well established that spikelet formation is a key yield‐determining step in rice 2,29 .…”

“…Si is transported to different parts of the rice plant largely along the transpiration stream, 34–36 with a transport gene responsible for loading Si into the grain and presumably the husk identified at the node beneath the panicle 15,37 . Compared with the Si concentration in field‐grown CNT1 and PTT1, 28 the Si concentrations in different plant parts of the same rice genotypes grown in solution culture in this experiment were very low. As 5% Si in the shoots at maturity is considered the critical level for deficiency, 2 Si was likely to be limiting for the rice plants in the present study, including those in +Si, where the shoots’ Si was less than 2%.…”

“…It is well established that spikelet formation is a key yield‐determining step in rice 2,29 . The role of Si in spikelet formation should therefore be particularly relevant in those rice genotypes that require more Si in their husk, 28 as well as in CNT1. Previous studies have reported direct roles of Si in sexual reproduction of plants; increasing Si supply was reported to increase pollen production and pollen viability in a plantain lily, ‘Krossa Regal’ ( Hosta Tratt.)…”

Silicon Application Promotes Productivity, Silicon Accumulation and Upregulates Silicon Transporter Gene Expression in Rice

“…The experiment was arranged in a factorial completely randomized design with three independent replications. The three modern rice varieties used in this experiment were Chainat 1 (CNT1), Pathumthani 1 (PTT1), and Khao Dawk Mali 105 (KDML105), selected with respect to their husk Si concentration, with 8.7%, 7.1%, and 6.7% dry weight of husk Si concentration, respectively [ 43 ]. Plants were grown in 15 cm-diameter pots containing 4 kg soil.…”