Sodium Nutrition of Pasture Plants I. Translocatign of Sodium and Potassium in Relation to Transpiration Rates

Abstract

A study of transpiration rates, and of uptake and translocation of sodium and potassium, has supported a previous classification made for certain pasture and fodder species. The plants termed natrophiles were found to have relatively high transpiration rates and to translocate relatively large amounts of absorbed sodium from root systems into leaves. Plants termed natrophobes had lower transpiration rates and translocated less sodium from roots to leaves. In contrast, potassium was readily translocated by both natrophiles and natrophobes; consequently, compared with natrophobes, natrophiles had low K/Na ratios in their leaves. In general, transpiration rate was less associated with absorption of sodium by roots than with translocation of sodium from roots to aerial parts. The practical and ecological implications of these results are discussed.

Element interconnections inLotus japonicus: A systematic study of the effects of element additions on different natural variants

“…In addition, K concentration was almost equal among roots, stems and leaves, while the concentrations of Na and Cs in the roots were much higher than in the shoots. This result is consistent with Smith et al . (1980), who reported that unlike the Brassica spp., legumes had relatively high K:Na ratios in their tissues and the ratios followed a sequence of root < stem < leaf, which indicated that in the Leguminosae, K was more effectively transported to the shoots than Na, and probably Cs.…”

“…In addition, K concentration was almost equal among roots, stems and leaves, while the concentrations of Na and Cs in the roots were much higher than in the shoots. This result is consistent with Smith et al (1980), who reported that unlike the Brassica spp., legumes had relatively high K:Na ratios in their tissues and the ratios followed a sequence of root < stem < leaf, which indicated that in the Leguminosae, K was more effectively transported to the shoots than Na, and probably Cs. It has been extensively reported that the addition of K can reduce Cs uptake by plants because of their chemical similarities (Bange and Overstreet 1960;Hampton et al 2004;Handley and Overstreet 1961;Isaure et al 2006;Shaw and Bell 1991), and that K and Cs enter root cells by the same molecular mechanism(s) (reviewed by White and Broadly 2000); while decreased K concentration in Arabidopsis was not observed until the Cs external concentration reached a toxic level (Hampton et al 2004).…”

Kikuyu-based pasture for dairy production: a review

“…They pointed out the significance of this difference in terms of the Na requirement of lactating cows and stressed that application of Na-containing fertilisers to pastures in a bid to increase the Na content of the forage to desirable levels will be unsuccessful if the dominant species are natrophobes such as kikuyu. In a subsequent paper, Smith et al (1980) demonstrated that kikuyu and other natrophobic grasses have an excessively high K/Na ratio in their leaves. More recently, Marais (2001), in a comprehensive review, stressed that kikuyu-dominated pastures cannot provide enough Na to grazing animals.…”

Maturity effects on mineral concentration and uptake inSolanum nigrumL.

“…Also, the current results from the field study were lower than those reported by Mahala et al (2012) who observed an increase in Na concentration with plant maturity. It has been observed that the extent to which Na is taken up by plants varies with species and is influenced by other minerals present in the soil especially K and N. Due to the chemical similarity between K and Na, competition for common absorption sites in the roots may lead most plant species to readily absorb K instead of Na even though the concentration of Na may be high in the soil (Smith et al 1980). Observation from the present study shows that S. nigrum readily absorbed K as compared to Na.…”