Abstract
A very important and well established chemical characteristics of salt affected soils relevant to crop growth is their .~ anionic compossion i.e- O-:SO/: ratio of soil solution. Rice soils (}f the upper Indus Plain (Punjab) in Pakistan , have SO/- type of saIiftily while; the rice soils of lower Indus (Sindh) dominate in CI- salinity. It was, therefore, an " economically important issue to study effect of different proportions of Cl and S042-in the saline medium on the rice growth, and their physiological implication by employing rice lines of known salt tolerance behavior. it Therefore: so~e.xperiments ...,..~ conducted to~termine whethes some appropriate external ratios of ions help "it to rnaintasn the ~wtabte internal blc compoottlorh-nd thus JoFnprovenee growth In the saline conditions. Hence, '., different ratios were established in the saline substrate involving two rice lines, i.e. NIAB 6 (salt tolerant) and BG \ 402-4 (less salt.tolerant). The effect of Cl : S04-2 ratios in the saline medium on the shoot and root weight of rice , was.eutstandinq; sh00t weight was almost twice as high at Cl: S04-2 ratio of 1:100 as compared to ratio of 100:1 while, this difference was more than twice in the case of root weight. On overall basis, the better growth of rice at lower Cl : S04-2 ratio was related to improved K+and Ca2 +concentrations in the leaf sap (led to high internal Ca2+ Na+and K "Na +ratios), and also a relatively lower P concentrations under saline conditions.
