Effects of drought stress and different nitrogen levels on morphological traits of proline in leaf and protein of corn seed (Zea mays L.).

摘要

This experiment was set up to understand the mechanisms causing yield limitations on crops subjected to water deficiency. The units were set out as a randomized complete block design with a split-plot arrangement with 4 repetitions at Azad Islamic University Research Center-Varamin-Pishva during the growing seasons of 2008 and 2009. The main factors tested drought stress at four stages (50, 100, 150 and 200 mm evaporation from the evaporation pan) and the sub factors were applications of nitrogen fertilizer at 3 levels (80,130,180 kg/ha). The experiment demonstrated that with increasing severity of drought stress, grain yield decreased sharply but increased with nitrogen fertilizer, the time taken for pollination, grain weight and total number of grains/ear were also affected. Results for plant height and diameter of first internode and total number of leaves above the ear (201.8 cm) were most affected by nitrogen fertilizer application of 180 kg/ha and 50 mm evaporation. Proline also increased significantly under drought stress conditions showing that osmotic adjustment mechanism had been activated. The highest level of leaf proline (180.2 micro mol/g NT) was achieved with 200 mm evaporation and 80 kg/ha of nitrogen fertilizer. Grain protein content was undesirably affected under extreme drought stress and fertilizer treatment.