Effects of Shading, Removal of Panicle and Foliar Application of Nutrient on the Formation of Superficial Roots of Rice Plants

Abstract

Rice plants, cultivar "Mubo- Aikoku", were grown in Wagner pots under conditions of 50 per cent shade, removing about half of each panicle, foliar spraying with 5 per cent glucose or 1 per cent urea solution four times and control. Treatments were carried out during the period between young panicle formation stage and full ripe stage, at which the formation of superficial roots could be observed. Regarding shade grown plants, the length of both primary roots and secondary lateral roots as well as the density of both secondary and tertiary lateral roots were lower than those of control. Concerning panicles removing and foliage spraying grown plants, the opposite trend was true as compared with shade treatment, i.e., the investigated features of superficial roots formation were several times higher than those of control. With respect to the formation of lateral roots, visual observation showed that spraying grown plants branched up to forth or fifth order, while those of shade treatment branched only up to tertiary. The formation rate of "lion-tail-like root", was greatly different among the treatments, i.e., this rate was higher for shade plants than control, and the opposite was true with panicles removing grown plants. According to the conjecture that both panicles removing and foliar application of nutrients are favourable for the nutrio-physiological conditions of tested plants, while shade is hazard; from the above results, it can be concluded that the formation of superficial roots as well as "lion-tail-like roots" was closely connected with nutrio-physiological conditions.