Effects of Root Temperature, Mineral Nutrition, and Salinity on the Growth and Composition of Rice
1958; University of Chicago Press; Volume: 120; Issue: 2 Linguagem: Inglês
10.1086/336004
ISSN1940-1205
Autores Tópico(s)Agriculture, Soil, Plant Science
Resumo1. Two water-culture experiments were conducted with Caloro rice grown at several constant root temperatures and several levels of nutrition or salinity. In the first experiment, growth of shoots, roots, and grain was decidedly better at a high than at a low cation level. Variations in cationic ratio brought about changes in cation content of shoots and roots. This altered cation content did not significantly affect vegetative growth, but grain yields were significantly greater on isoequivalent (Ca=Mg=K) and high-K solutions than on high-Ca or high-Mg solutions. At a constant root temperature of 18⚬ C., shoot growth was twice that at 30⚬ C., and root growth one and a half times as great; however, grain yield was only three-fourths as much at the lower root temperature. There were no statistically significant interactions between root temperature and cationic concentration or cationic ratio. 2. In the second experiment the nutrient solution which had allowed the most growth (the isoequivalent solution at the high cation level) was used as a base nutrient in a study of root temperature and salinity effects. Rice was grown only to the late-flowering stage, at which time the two lower constant root temperatures, 22⚬ and 14⚬ C., had brought about less top growth than 30⚬ C. Two atmospheres of chloride (NaCl, CaCl2, or mixed NaCl and CaCl2) added to the base nutrient were appreciably more inhibiting than sulfate (Na2SO4). Shoots accumulated two to three times as much chloride (up to 60-90 meq/100 gm dry wt.) on the chloride solutions as on the non-saline medium. Four atmospheres of NaCl were lethal at all three root temperatures. The interaction between salinity and root temperature was not statistically significant.
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