The Absorption of Inorganic Ions by Chlorella pyrenoidosa.

Abstract

GREGORY ET AL-CO2 AND PHOTOPERIODISM metabolism and photoperiodism. Thesis In the course of experiments on the effect of radioactive elements on the growth of Chlorella pyrenoidosa, Porter and Knauss (9), determinations were made of the content of a radioactive element in algal cells when the ratio of that element to its stable isotope was kept constant, but the total concentration of the two isotopes in the solution was varied. Calculations were then made, assuming no isotope effect, of the total contents of the two isotopes in the algal cells. These determinations were made for the elements P, S, Ca, Fe, Mn, Zn, Cu, and Sr.A limited amount of information is available on the effect of the nutrient concentration of an element on the uptake of that element by algae. Scott (11) has reported that the ratio of uptake of calcium and magnesium by Chlorella depends upon the ratio of these two elements in the nutrient solution. Scott (12) has also studied the behavior of phosphatedeficient cells during a restoration period when adequate phosphate was supplied to the nutrient medium. He found the phosphate uptake to be proportional to the nutrient concentration only at levels that were limiting for growth.More information on the effect of nutrient concentration of an element on its uptake has been obtained through studies with higher plants and diatoms. Beckenbach et al (1), in making a statistical analysis of the relationship between the ionic content of the culture solution and the element content in corn plant tissues, found the most important single factor affecting the absorption and accumulation of an element in plant tissues to be its absolute concentration in the nutrient solution. Similar results were reported by Tidmore (14) on corn, sorghum, and tomatoes, and by Beeson et al (2) on tomato plants. Recently, Rediske and Selders (10) reported the uptake of strontium by plants to be proportional to the concentration of this element in the nutrient solution. Goldberg et al (5), working with diatoms, found the phosphate uptake to be proportional to the concentration in the medium over the range 0.5 to 3.5 ,ug/l. Similar findings were reported by Ketchum (7). Seven and one half ml of nutrient solution (KNO3, 3.0 gm/l; MgSO4 * 7 H20, 4.8 gm/l; Ca(NO3)2, 1.0 gm/l; KH2PO4, 3.0 gm/l; MnSO4 * H20, 2.0 mg/l; H3BO3, 2.0 mg/l; CUSO4-5 H20, 0.2 mg/l, and ZnSO4-7 H20, 0.2 mg/l), less the element being investigated, were added to 20 x 150 mm culture tubes. Varying amounts of the element being studied and the appropriate amounts of water were added to each tube. After sterilization each tube received 0.2 ml of a sterile iron solution (1 gm FeSO4 -7 H20/500 ml), 1.0 ml of inoculum (an optical density of 0.60 at 660 mnA/18 mm tube, approximately 17 x 106 cells/ ml) and amounts of a solution containing a radioactive isotope of the element under study to yield a final specific activity of one mc/gm of that element.In experiments on the absorption of copper the specific activity was 3 to 8 mc/gm of element. Radioisotopes used were p3...

Ion Absorption and Retention by Chlorella pyrenoidosa. I. Absorption of Potassium

“…In a previous paper (21), we presented data obtained when water was allowed to evaporate through commercial screens, and interpreted the results in terms of stomatal diffusion. The rule proposed by Brown and Escombe (3) and others (11,23) New screens made to our order, with pores 2.5 to 80 ,u in diameter and, for some sizes, 10 to 160 diameters apart, have enabled us to survey the problem of multiperforate diffusion in considerably greater detail than has previously been possible.…”

“…In most nutritional studies the effect of treatmlents were estimated by some measurement of net growth (6,12) ; only in some cases was the change in internal composition nmeasured ( 11,21,22). Thus, in many studies the actual cause of the observed changes or the lack of response to treatments is difficult to ascertain.…”

MECHANISM OF RADIOACTIVE ZINC UPTAKE BY ULVA LACTUCA1

“…Previous studies of zinc uptake by algae have been conducted by Knauss and Porter ( 1954), who found that the amount of Zn@ absorbed by Chlorella cultures varied with the concentration of zinc in the media. Rice ( 1958) reported a rapid and almost complete absorption of Zns5 by Nitzschia cultures in both the light and the dark, with resulting cell concentration factors up to 58,000.…”

Influence of the Counter-ion on the Absorption Isotherm for Chloride at Low Temperature

“…Deviations fromii this general rule can be causecl by a variety of circunmstances ancl range from a reported independence of concentration over a wide range for ioIn uptake by rye plants ( 10) to a (lirect proportionality to concentration for uptake of several ions 1y Clhlorella (7). A unique anonmaly in whiclh chloride uptake by potato disks at 00, resenmbled an exponential function of concentration was b)rieflv noted b1 Laties (8) and lhas now been further investigated.…”