Relationship between the numbers of crown roots and stems per hill in rice plants
2004
Katano, M. (Kyushu Tokai Univ., Choyo, Kumamoto (Japan). Faculty of Agriculture)
Abstract : Crown roots consist of elongating roots and stunted roots, and are classified into upper shoot unit roots, lower shoot unit roots, and prophyll shoot unit roots according to shoot unit theory. The relationship between the numbers of crown roots and stems was examined in 18 hills each cultured in 1/2000a Wagner's pot with different fertilizations. In this experiment, the number of stems per hill varied from 3 to 85. The number of elongating roots highly correlated with the number of stems per hill. It increased at a rate of 32.1 per stem when the number bf stems in a hill was fewer than30, but at a rate of only 9.4 per stem when the number of stems per hill was larger than 30. Thus, the number of elongating roots plotted against the number of stems per hill was regressed to two lines with sharp and gentle inclinations. The stem number at the intersection of the two regression lines was 26.8. The numbers of upper shoot unit roots, lower shoot unit roots and prophyll shoot unit roots plotted against the stem number were also regressed to two lines, and the stem numbers at the intersections were 23.3, 27.3 and 33.1, respectively. The total number of crown roots including elongating and stunted roots highly and positively correlated with the number of stems, and regressed to a single line, not to two lines with different inclinations.
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