Changes in Yield and Chloroplast Mg2+-ATPase Activity of Wheat (Triticum aestivum L.) in Response to Soil Salinity and Nutrient Supply | ||||
| Alexandria Science Exchange Journal | ||||
| Article 14, Volume 38, April-June - Serial Number 2, June 2017, Page 284-293 PDF (290.54 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/asejaiqjsae.2017.3473 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| Mahmoud Kamh; Attiat El-Hamrawy | ||||
| Soil & Water Science Dept. Faculty of Agriculture, Alexandria University, Egypt. | ||||
| Abstract | ||||
| Under stress conditions such as salinity and drought, plant tolerance depends on upregulating ATPase activity. A greenhouse and a field experiments were conducted to investigate the regulation of chloroplast Mg+2-ATPase activity in wheat in response to soil salinity and nutrient supply. In the greenhouse, plants were imposed irrigation with three water salinities; 0.4, 4.0, and 8.0 dSm-1 with different sub-treatments of nutrient applications. Wheat yield was negatively correlated with soil salinity, presenting threshold at 6 dSm-1 followed by yield reduction with slope 7.4 % per unit dSm-1. Salt stress decreased Mg+2-ATP activity from 0.32 to 0.28 µmole Pi min-1 mg-1chl. Application of mixed fertilizers M.F. (compost, Gypsum, P, and K) for the non stressed plants resulted in increasing both Mg2+-ATPase from 0.32 to 0.40 and the relative grain yield to 120%, suggesting anabolic metabolism. At soil salinity above the threshold level, application of nutrients sharply increased Mg2+-ATPase activity up to 1.06 µmole Pi min-1 mg-1chl accompanying yield reduction; suggesting catabolic metabolism. In the field experiment, the soil salinity was 12.3 dSm-1 at planting and only drainage water (EC 3.9 dSm-1) was available for irrigation. The soil EC steeply reduced to 5.0 dSm-1 before the productive growth stages. Mg+2-ATPase activity was up-regulated at flowering and was low late in the season at the grain filling stage. Foliar spray with K+ and a biostimulant enhanced ATPase activity as well as grain yield compared to the control. Under the field condition Mg2+-ATPase activity was correlated with the grain yield, which reached 8.7 Mg ha-1. The variation in wheat response in the greenhouse to that in the field may be attributed to the greenhouse conditions that impaired photosynthesis activity and induced catabolic ATP hydrolysis. | ||||
| Keywords | ||||
| Wheat; Mg2+-ATPase; Soil salinity; Grain yield | ||||
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