Growth response of cabbage plants to transition elements under water culture conditions

Cabbage plants were water-cultured under 4 levels of cobalt (0, 0.05, 0.5, 5 ppm), nickel (0, 0.04, 0.4, 2 ppm), copper (0, 0.1, 0.5, 2,5 ppm), zinc (0, 0.4, 2, 10 ppm), and molybdenum (0, 0,1, 1, 10 ppm), and tlte effects were studied of the transition dements including other elements (Ti, V, Cr, Mn, and Fe) in the preceding report on the growth of the plants and on the distribution of the elements in the plants. The dry weight of a whole plant and of inner leaves (yield) without the addition of Zn and Mo decreased slightly. The critical contents of Zn and Mo in outer leave? which resulted in a slight decrease in the yield due to the deficient injury were estimated to be about 15 and 0.2 ppm. The yield decreased at high levels of all the transition elements in the culture solution, and the contents of Co, Ni, Cu, Zn, and Mo in outer leaves when the yield decreased by 50% due to the excess injury were about 30, 70, 25, 400, and 200 ppm, respectively. Cabbage plants were considered least tolerant to the excess of Ti and V. slightly tolerant to Cr, Co, Ni, and Cu, and most tolerant to Mn, Fe, Zn, and Mo on the basis of the results of the element contents in plant-tops. And, Ti, V, Cr, Fe, and Cu seemed to cause the excess injury with such tendencies as they accumulated mainly in roots and Mn, Co, Ni, Zn, and Wo as they were translocated into all the organs.