Selectivity of the root absorption of nutrient ions in grain sorghum

Abstract

Root absorption selectivity, which refers to the fact that the mineral elements are not found in the same proportions in the plant as in the growth medium, was characterized using plots where the proportions between the elements were considered. Grain sorghum was grown hydroponically in nutrient solutions where the cationic macroelements were increasingly replaced with sodium and the anionic macronutrients with chloride. The data obtained from the analyses of the nutrient solutions and of the whole plants show that root selectivity promotes the absorption of K + and NO 3 --N and impedes that of Ca ++ whereas there is nearly no selectivity towards the other nutrients (Mg, P, S).The high negative selectivity towards unessential elements (Na and Cl) is reflected by their very low proportions within the plant.

Effects of calcium deficiency on nutrient concentration of xylem sap of excised tomato plants

“…The decrease of the Ca content in the root tissue of plants with treatment -Ca is not significant enough to impair the invariability of the cation sums, a general phenomenon already demonstrated in plant nutrition physiology of intact tomato plants (Fong, 1973 ;Pujos and Morard, 1997) and sorghum (Morard et al, 1990).…”

Stimulation of the growth and solamargine production by Solanum paludosum multiple shoot cultures using a new culture medium

“…Macronutrient contents were analysed by classical methods (Morard et al, 1990) after a sulfuric acid mineralisation for total nitrogen and nitric acid for: N and P by automatic absorption spectrophotometry, S by turbidimetry and K, Ca, Mg by atomic absorption spectrophotometry.…”