Root restriction has been reported to reduce fruit yield, the incidence of blossom end rot (BER) and K concentration in tomato (Lycopersicon esculentum L. `F121') plant organs. The objectives of the present work were to study the effect of root restriction, and combination of K and Ca solution concentrations, on greenhouse tomato fruit yield, quality and cation uptake. Root restriction reduced total yield but improved fruit quality by increasing the dry matter concentration and reducing the incidence of BER. Increasing the K concentration from 5.0 to 10 mmol·L-1 reduced the marketable yield, due to increased incidence of BER. Root restriction decreased K concentration and K/Ca ratio in tomato plant organs, but had no effect on K uptake rate per unit root fresh weight. Increasing K concentration from 2.5 to 10 mmol·L-1 increased the K concentration in plant organs and K uptake rate, but reduced that of Ca. In contrast, increasing Ca concentration in the solution had no effect on K concentration in plant organs and K uptake rate. The incidence of BER correlated well with K/Ca concentration ratio in the leaves, whereas a poor correlation was obtained with K/Ca concentration ratio in ripe fruit.

The effect of N and K nutrition on the salt tolerance of lettuce (Lactuca sativa L. cv. 'Salinas') and Chinese cabbage (Brassica campestris L., Pekinensis cv. Kazumi) was evaluated in three greenhouse experiments under a controlled aero-hydroponic system of cultivation. Three levels of KNO3 (1, 5 and 10 mM) were tested in all the experiments with rapidly circulated saline and nonsaline nutrient solutions. Two experiments, carried out between January and March 1989, with lettuce (Exp. I) and Chinese cabbage plants (Exp. III), consisted of two salinity levels, EC= 1.75 and 6.0 dS m-l, the former representing a nonsaline nutrient solution. In the third experiment with lettuce (Exp. II., conducted between March and May 1989), three saline nutrient solutions having EC levels of 4.7, 7.75 and 10.75 dS m-1 were compared to the nonsaline solution. The nutrient solutions were salinized with NaC1 and CaC12, in a 4:1 molar ratio. The highest yields of fresh weight of both crops were obtained from the 5 mM KNO 3 under both saline and non-saline conditions. The 10 mM treatment caused yield reduction in Chinese cabbage, probably due to a severe tipburn disorder. The relatively high fresh weight yield obtained at the lowest (1 raM) KNO 3 level can be explained by the positive effect of circulation velocity on nutrient uptake. The threshold salinity damage value for the vegetative yield of lettuce plants fed by 5 or 10 mM KNO 3 was approximately 5 dSm -1 and the yield decreased by 6.5% per unit dS m-1 above the threshold. No yield improvement due to the addition of KNO 3 occurred under highly saline conditions (Exp. II). The fresh weight of Chinese cabbage obtained from the 'saline' 1 and 5 mM KNO 3 treatments was approximately 15% lower than the 'non-saline'-treatment (Exp. III). Salinity increased tipburn and the effect was not altered by the addition of KNO 3 . No significant interaction between nutrition (KNO 3 level) and salinity was found. The application of salts increased the concentration of Na and C1 * Contribution from Institute of Soils and Water, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel. No. 3092-E 1990 series Offprint requests to: A Feigin in plant tissue and reduced the levels of N and K; the opposite occurred in plants fed by the medium and high levels of KNO a .The yield and quality of leaf vegetables, such as lettuce and Chinese cabbage, grown on irrigated land can be considerably influenced by water composition. This is also true for greenhouse-grown crops when saline water is used for irrigation or, when grown in soil, where a high water table or the accumulation of fertilizer residues contributes to the development of saline conditions (Sonneveld 1988). Alleviation of salt stress in leaf vegetables is important not only to prevent yield losses but also to avoid quality deterioration due to physiological disorders such as tipburn van den Ende et al. 1975).As salt damage to crops involves not only total salt effect (osmotic effect) but also specific ion effects (Lauchli and Epstein 1984) it has b...

Doses of .66 to .99 mg monensin/kg body weight reduced legume bloat in cattle about 66% when compared with pretreatment bloat scores. Similar doses of lasalocid reduced legume bloat about 26%. A dose of 44 mg poloxalene/kg body weight (recommended dose for field use) reduced legume bloat 100%. Monensin or lasalocid combined with 25 or 50% of the recommended dose of poloxalene reduced bloat under that of the antibiotics alone, but did not achieve 100% reduction. The antibiotic thiopeptin provided no preventive effect on legume bloat. Lasalocid, monensin or an experimental polyether antibiotic (X-14,547 A) at a dose of 1.32 mg/kg body weight when tested on cattle bloated on high grain diets reduced bloat by 92, 64 and 25%, respectively. Lasalocid at .66 mg/kg effectively prevented bloat from developing when given to animals before the feeding of high grain diets; however, a 1.32-mg dose was required to control bloat in cattle that were already bloating before they were given lasalocid. A dose of 1.32 mg salinomycin was ineffective in controlling grain bloat.

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