Organic fertilizer application increases anther length and number of engorged pollen grains in rice plants
2008
Taki, N.(Miyagi-ken. Furukawa Agricultural Experiment Station, Osaki (Japan)) | Asano, M. | Kumagai, C. | Hatanaka, A. | Saito, K.
Organic fertilizer (OF) is widely applied in paddy fields because of a growing environmental consciousness among farmers. However, no studies have examined the effect of easily decomposable OF on the cold tolerance of rice plants. In this study, we examined the effects of easily decomposable OF on anther length and the number of engorged pollen grains, as these characteristics are closely related to cold injury. Readily available inorganic fertilizer (RAF) and controlled-availability inorganic fertilizer (CAF) were used as controls. During our observations in 2005 and 2006, air temperatures were not sufficiently low to damage rice plants. In 2005, the number of engorged pollen grains ranged from 1089 to 1319 per anther in the RAF plots, versus 1291 to 1351 in the OF plots (an increase of approximately 10% ). The number of pollen grains in the CAF plot was 1389, similar to that in the OF plots. In 2006, the number of pollen grains ranged from 1016 to 1137 in the RAF plots, versus 1197 to 1239 in the OF plots. Anther length was longer in the OF and CAF plots than in the RAF plots. The number of engorged pollen grains in the RAF plots was significantly negatively correlated with the number of rice grains per square meter, whereas those in the OF and CAF plots showed no correlation. Thus, the number of engorged pollen grains in the OF and CAF plots was greater than that in the RAF plots at the same grain density. Furthermore, the number of engorged pollen grains in the RAF plots was significantly negatively correlated with the nitrogen content of the shoots at meiosis (a factor that was most sensitive to cold weather), whereas those in the OF and CAF plots showed no correlation. These results suggest that the slow release of nitrogen from OF and CAF increased anther length and the number of engorged pollen grains.
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