| Abstract: | The effects of 2-chloroethyltrimethylammonium chloride (CCC)and 2,4-dichlorobenzyl-tributylphosphonium chloride (Phosfon)on the growth of pea plants in sand culture at two rates ofapplied phosphorus (P), were studied in controlled-environmentgrowth chambers. CCC at 1 and 10 mg/1, and to a lesser degreePhosfon at 0.1 mg/1, stimulated growth. CCC at 1000 mg/1 andPhosfon at 100 mg/1 retarded growth, due mainly to shortenedstems. The magnitude of such effects depended on the level ofapplied P. Reductions in plant height by the 1000 mg/1 CCC treatmentwere 13 and 50 per cent respectively at the high (160 mg/1)and low (8 mg/1) rates of applied P. Similar decreases due to100 mg/1 Phosfon were 30 and 57 per cent respectively. At thehigh P rate, both CCC and Phosfon had no significant effecton total uptake of P, or on relative distribution in the leaf,stem, and root. At the low P rate, the root, relative to leafand stem, retained more P, at a CCC concentration of 1000 mg/1.With Phosfon at 100 mg/1 relative leaf P content increased whilethat of the stem and root decreased. Phosfon was more activethan CCC in terms of the concentration required to cause a givenmagnitude of growth effect. |
