Revista Ciência Agronômica
On-line version ISSN 1806-6690
ALVES, Francisco Abel Lemos et al. Kinetics of K+ absorption in the absence and presence of Na+ in roots cashew tree. Rev. Ciênc. Agron. [online]. 2012, vol.43, n.3, pp. 439-445. ISSN 1806-6690. http://dx.doi.org/10.1590/S1806-66902012000300004.
One effect of the salinity caused by an excess of Na+ in soils, is the reduction in levels of K+ in plant tissue. The study aimed to characterize the process of high and low-affinity absorption of K+ in cashew roots, in both the absence and presence of concentrations of Na+. Studies of the kinetics of K+ absorption in the absence and presence of NaCl were carried out using detached roots from cashew seedlings grown under K+ deprivation. The excess of Na+ in the external environment caused a reduction in K+ absorption by both the high and low-affinity systems. The reduction in the absorption of K+ in the roots of the cashew tree, caused by the excess Na+ in the environment, happens through competitive means. This type of competition was evidenced by the increase in Km values for the K+ absorption induced by the external Na+, without changing the values of Vmax. The results show that salinity may affect the acquisition and use of K+ in cashew plants.
Keywords : Cashew; Plants-effect of salt; Plants-effect of potassium.