Sodium Translocation Research Articles

Absorption and Translocation of Sodium in Beans and Cotton

At the end of a 4 hour absorption period approximately 95% of the sodium absorbed by bean plants was retained in the secondary roots. The sodium translocated to the shoot was retained in the stem.2,4-Dinitrophenol decreased the amount retained in the secondary roots of bean plants and increased the amount translocated to the shoot. The stem retained most of the translocated sodium.Bean plants without roots absorbed considerably more sodium than plants with roots and translocated a greater proportion of the sodium to the petioles and blades. 2,4-Dinitrophenol reduced the amount of sodium in the stem and petioles and increased the amount in the blades.2,4-Dinitrophenol reduced the amount of sodium retained by the secondary roots of cotton plants but did not appreciably affect the amounts translocated to the shoot.

The foliar absorption by cacao of P32-labelled sodium, potassium, and ammonium phosphate as influenced by pH

Seedlings ofTheobroma cacao L. were used to study the absorption and translocation of P32-labelled sodium, potassium, and ammonium phosphates applied to a single leaf. The pH of the solutions were whole number values between 2 and 12 for sodium and potassium, and between 2 and 10 for ammonium phosphates. All solutions were 0.1M. Maximum absorption occurred at pH2 with potassium, 10 with ammonium, and 5 with sodium. No consistent relationship was found between absorption and hygroscopicity of the 8 salts used.

Translocation of potassium and sodium in intact maize seedlings

The distribution of K and Na between root and shoot of intact maize seedlings after absorption periods of increasing length up to 24 hours was determined in three series of experiments. In two additional series the redistribution between root and shoot of K and Na absorbed previously during a period of 12 hours was followed up during the next 12 hours. Concentrations were such that either the specific or both the specific and non-specific mechanism of K-absorption present in this tissue were operative. A high degree of specificity in the transfer to the shoot became apparent, the amount of Na transported to the shoot within 24 hours being negligible in comparison to the amount of K transferred within the same period. For the most part this specificity appeared to be due to the fact that the specific mechanism of K-absorption is especially involved in the supply of K for transfer to the shoot. However, non-specifically absorbed K is also liable to transport to the aerial parts at a much higher rate than Na and, in contrast to Na, the translocation of K continues after the plants have been transferred to K- and Na-free media. A scheme is proposed to explain the phenomena described.

Effect of Application of Sugar on the Translocation of Sodium 2,4-Dichlorophenoxyacetate by Bean Plants in the Dark

1. A drop of an aqueous solution of sodium 2,4-dichlorophenoxyacetate (containing 70-100 μgm.) was applied to the upper surface of one of the primary leaves of each of a number of Red Kidney bean plants, some of which were kept in the light before and after application of the growth-regulator and some of which were kept in the dark for 24 hours before and after treatment. The leaves of some of the plants in the dark were dipped in sucrose solution several times shortly (1-3 hours) before the growth-regulator was applied. Sugar was supplied to still other plants by placing the cut end of one of the primary leaves of each plant in a vessel containing a 10% sugar solution. 2. The curvatures of the stems were measured 24 hours after application of the herbicide, and the treated leaves were removed at this time. The plants were then placed in the greenhouse for 10 days, at the end of which time the weight of the trifoliate leaves from each plant was determined. 3. No evidence was found that Na(2,4-D) was trans...