| Abstract: | Effect of P-deficiency in the split-root-system on lipoid root characteristics of rape-seed ( Brassica napus L.)
The effect of partial P-deficiency on characteristics of parts of the root system from rape-seed ( Brassica napus L.) was investigated by means of the split-root-technique. At 1 cm length of the seventh leaf treatments started lasting 21 days. Pots were designed with two separated chambers filled up with nutrient solutions. Both halfs of the root system lacked of P (-/-) or were fully fed (+/+). Additionally, one part of the root system was fully supplied while the other part was kept without P (+/-). The root system grown at partial P-supply revealed compensatory reactions which became evident by increased uptake of K and Ca and by higher contents and amounts of lipid-P as compared to the P-deficient root portion. The fatty acid composition of the major phospholipids from root tissue, phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE), varied in dependence of P-nutrition. At P-deficiency the linoleic acid content (% 18:2) declined while the linolenic acid content (% 18:3) increased. Consequently, no change in saturation occurred. However, in PE the degree of saturation was affected distinctly. P-deficiency caused an increase of saturation whereas full supply led to higher desaturation. The results point to relations between the intensity of nutrient uptake modulated by P-nutrition and the amounts and characteristics of membrane lipids in root tissue. |
