نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشیار، گروه تولیدات گیاهی، دانشکده کشاورزی، مجتمع آموزش عالی گناباد، گناباد، ایران (آدرس فعلی: دانشیار، مأمور آموزشی، گروه اگروتکنولوژی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
2 دانش‌آموخته کارشناسی ارشد، پژوهشکده گیاهان و مواد اولیه دارویی، دانشگاه شهید بهشتی، تهران، ایران
3 دانشجوی دکتری، گروه اگروتکنولوژی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Maize (Zea mays L.) is one of the vital crop in the world, serving as a significant food source and primary income for farmers, particularly in developing countries. It is also a key raw material for various industries, including biofuel (ethanol) production. Moreover, drought stress, as one of the most important environmental limiting factors, severely affects the growth, productivity and yield of maize. Sustainable and eco-friendly solutions, such as the application of micronutrients and plant growth regulators, can effectively enhance plants drought tolerance. Essential micronutrients like iron (Fe) and zinc (Zn) play crucial roles in plant physiological and biochemical processes. Iron is involved in nitrogen fixation processes and antioxidant enzyme activity, while zinc is vital for chlorophyll synthesis and carbohydrate metabolism. Additionally, salicylic acid (SA), as a plant growth regulator, is known to improve plant drought resistance. Given the arid and semi-arid climate of Iran and the scarcity of water resources, it is essential to investigate innovative strategies to improve maize performance under these conditions. The objective of this study was to evaluate the effects of combined application of iron and zinc micronutrients along with salicylic acid on yield and growth characteristics of maize under drought conditions.
Materials and methods
The experiment was conducted as a split plot factorial in a randomized complete block design with three replications at the University of Gonabad, Khorasan Razavi Province, Iran, in 2019-2020 growing season. Irrigation at two levels including normal irrigation (non-stress or control) and drought stress (complete cutoff irrigation from the grain filling stage) was considered as the main factor and salicylic acid at two levels (foliar application and non-application or control), and micronutrient foliar application at three levels (Fe, Zn, and non-application of micronutrient or control) were considered as sub-factors. Minimum tillage was employed for land preparation. The used maize variety was SC704, which is a high-yielding grain maize variety suitable for cultivation in semi-arid to temperate regions with relative resistance to environmental stresses, especially drought. The measured traits included plant height, ear diameter and weight, number of grains per row, 1000-grain weight, grain yield, and harvest index. Statistical analysis of the data, including analysis of variance and comparison of means with Duncan’s multiple range test, was performed using SAS software ver. 9.4 and the graphs were drawn using Excel software ver. 14.
Research findings
The results showed that drought stress significantly reduced all the studied traits, however, foliar application of salicylic acid and micronutrients of iron and zinc effectively reduced the negative effects of drought. The simultaneous foliar application of SA with Fe and Zn, especially under drought conditions, led to a significant improvement in most of the studied traits, such as number of grains per row, 1000-grain weight, grain yield and harvest index, so that the combined application of SA along with Fe and Zn under drought conditions resulted in the greatest increase in grain yield (94.36% and 87.35%, respectively) and harvest index (77.42% and 99.42%, respectively) compared to other treatments. Also, foliar application of zinc had more favorable effects on ear diameter, grain yield and harvest index than iron. Moreover, foliar application of salicylic acid under drought stress conditions increased key traits including plant height and 1000-grain weight by 16% to 37%. Also, combination of salicylic acid and micronutrients synergistically enhanced the positive effects of their separate application.
Conclusion
The results of this study showed that foliar application of salicylic acid and micronutrient iron and zinc can be an effective strategy to reduce the negative effects of drought stress in maize. The combined application of these substances significantly improved the yield and physiological characteristics of maize plant. While foliar application of each micronutrient (iron or zinc) together with salicylic acid led to positive results, investigating the synergistic effects of the combined application of both micronutrients together with salicylic acid in future studies can clarify the metabolic pathways of drought resistance, such as antioxidant enzyme activity and phytohormone synthesis, and provide more optimal strategies to increase maize productivity in arid and semi-arid climate regions.
کلیدواژه‌ها [English]
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