Barley (Hordeum vulgare L.) is a typical ammonium ( NH4 + )‐sensitive crop species and exhibits a futile‐ NH4 + efflux from root cells. Plasma membrane (PM) H+‐ATPase is responsible for pumping H+ out of plant cells and providing the driving force for the transport of various substances. We hypothesized that PM H+‐ATPase is involved in this NH4 + efflux process of barley roots. Barley plants were cultivated in hydroponic solution with 1.0 mM NH4 + or 1.0 mM nitrate ( NO3 - ) as the sole nitrogen source. Plasma membrane vesicles were isolated from the root tips for analyses of the activity. Plasma membrane H+‐ATPase was tested by Western Blot. The transcription of PM H+‐ATPase genes was analyzed using qRT‐PCR. Proton and NH4 + efflux from barley roots was analyzed by scanning ion‐selective electrode technique. The results show that root and shoot growth was repressed by NH4 + nutrition when compared to NO3 - nutrition. Plasma membrane H+‐ATPase activity of barley roots under NH4 + nutrition was significantly higher than that under NO3 - nutrition. Methyl‐ammonium (MeA), a non‐metabolizable analog of NH4 + , had no significant effect on PM H+‐ATPase activity. The enhanced PM H+‐ATPase activity by NH4 + nutrition was consistent with a higher abundance of PM H+‐ATPase protein and higher transcription levels of six PM H+‐ATPase genes. By using the pharmacological agents vanadate and fusicoccin, a close linkage was observed between H+ efflux and NH4 + efflux from barley roots. Taken together, NH4 + nutrition stimulates PM H+‐ATPase activity, and this stimulation is possibly triggered by NH4 + assimilation in barley roots. NH4 + efflux from barley roots is associated with PM H+‐ATPase activity which could provide the driving force for NH4 + efflux. Ammonium efflux might be considered as a disposal strategy in barley roots which prevents NH4 + overloading the root cytoplasm.

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The pod borer Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an important insect pest of chickpea and several other crops in Asia, Africa and Australia. The present studies were carried out on integration of various practices for the management of H. armigera in Punjab, Pakistan, during 2004-05. Chickpea variety 'CM-2000' was selected for evaluating various strategies such as cultural, mechanical, biological, microbial, and chemical control, individually and in various possible combinations, for the management of H. armigera at three different locations. Integration of weeding, hand picking and indoxacarb (an oxadiazine insecticide) proved to be the most effective in reducing the larval population and pod infestation and resulted in the maximum grain yield. The larval population of the combined effect of these practices was not significantly different from hand picking + indoxacarb, weeding + indoxacarb, and indoxacarb alone. Hand picking in combination with Bacillus thuringiensis, and weeding+hand picking, also controlled the larval population significantly, but was inferior to the above treatments. The release of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) did not control H. armigera. It was concluded on the basis of the cost -benefit ratio that hand picking was the most costeffective method for the control of H. armigera, while the maximum increase in grain yield was obtained in plots with weeding, hand picking, and indoxacarb.

Analysis of producers' and intermediaries' livestock price expectations was used to describe the market in Quetta, the largest livestock market in the highlands of Balochistan Province, Pakistan, and to identify factors that determine price expectations of small ruminants. A total of 4800 expected prices for sheep and goats were collected from producers and market intermediaries at monthly intervals between January 1991 and December 1992. In addition to the expected price of the animal, liveweight, species, sex, breed, body condition (fatness), calendar day and month were recorded, and whether data were collected on a meat or meatless day. Monthly rainfall data were also collected. Models of goat and sheep price expectations were built to compare the similarity of the behaviour of producers and intermediaries. Results indicated that producers and intermediaries expected high prices from November to January and during religious holidays. They expected premiums and discounts related to animals' attributes. Liveweight and seasonality had the strongest effect on prices. Rainfall in the current and previous month was positively related to seller's expected prices suggesting that livestock are retained to take advantage of favourable grazing conditions. The models of price expectations showed that producers adjusted expected goat prices (P ~ 0.10) for seasonality, liveweight, body condition, age, sex and breed, while they adjusted sheep prices for seasonality and liveweight only. High pay-offs could be expected if extension efforts focused on factors that determine sheep meat quality; however, the retail ceiling price of meat and the lack of grading are a disincentive to work in this direction. Seasonality of supply and demand is important in determining prices and this study provides baseline information for market scheduling; however, scheduling of sales of transhumant pastoralists may be difficult to achieve. Further investigation is justified to understand the gap in marketing knowledge between producers who sell in the villages and those who sell in Quetta. Livestock production and marketing constraints have been identified as the major factors that limit animal offtake in the highlands of Balochistan Province, Pakistan (Nagy et al., 1991).

Background Sorghum roots release two categories of biological nitrification inhibitors (BNIs)hydrophilic-BNIs and hydrophobic-BNIs. Earlier research indicated that rhizosphere pH and plasma membrane (PM) H + ATPase are functionally linked with the release of hydrophilic BNIs, but the underlying mechanisms are not fully elucidated. This study is designed to reveal further insights into the regulatory mechanisms of BNIs release in root systems, using three sorghum genetic stocks. Methods Sorghum plants were grown in a hydroponic system with pH of nutrient solutions ranging from 3.0 9.0. Pharmacological agents [(fusicoccin and vanadate) and anion-channel blockers (−niflumic acid (NIF) and