LEVELS OF CATIONIC MACROELEMENTS, SODIUM AND PHOSPHORUS DURING DEVELOPMENT AND SENESCENCE OF RAY FLORET IN CHRESANTHEMUM
Changes in the levels of essential cationic macroelements, sodium and an anionic macroelements (phosphorus) were estimated using an atomic absorption spectrophotometer during twelve stages of ray floret development and senescence. This was carried out as a continuation of our earlier studies which showed the importance of potassium in ray floret expansion. The amounts of cationic elements, excepting iron, increased till day 24 (i.e., the stage at which ray florets attain their maximal length, fresh and dry weights), whereas the content of iron and phosphorus increased only till day 20. Thereafter the content of all these elements registered a decrease. The increase in ionic content during development, besides activating some important metabolic enzymes, may play a role in increasing pressure potential, leading to uptake of water for cell expansion. Potassium and calcium were present at higher concentrations representing about 17.0 and 16.6 ug/floret respectively by day 24 (showing 4.0- and 3.4- fold increases over 0-day values, respectively). The maximum amounts of magnesium, sodium, iron and phosphorus recorded were approximately 3.70, 0.42, 0.13 and 0.45 μg/floret respectively.
Mohan Ram, H.Y. and Pardha Saradhi, P. (1989). LEVELS OF CATIONIC MACROELEMENTS, SODIUM AND PHOSPHORUS DURING DEVELOPMENT AND SENESCENCE OF RAY FLORET IN CHRESANTHEMUM. Acta Hortic. 261, 287-292