اثر هورمون¬هاي سيتوكينين و اكسين بر تجمع كلر و برخي عناصر پرمصرف در ذرت در الگوهاي مختلف كاشت در شرايط شوري

The Effect of Cytokinin and Auxin Hormones on the Distribution and Accumulation of Chlorine and Some Macroelements in Different Sectors of Maize in Different Planting Patterns in Saline Condition

جهت بررسی اثر مصرف هورمون (عدم مصرف (شاهد)، مصرف سیتوكینین در مرحله V8-V10 و مصرف اكسین در زمان ظهور ابریشم) و الگوی كاشت (یك ردیفه، دو ردیفه و كف فارو) بر تجمع كلر و برخی عناصر پرمصرف در ذرت در شرایط شوری آزمایشی به صورت كرت¬های خرد شده در قالب طرح بلوك¬های كامل تصادفی با سه تكرار در مركز تحقیقات و آموزش كشاورزی و منابع طبیعی بوشهر در سال 1393 اجرا شد. الگوی كاشت به عنوان عامل اصلی و مصرف هورمون به عنوان عامل فرعی در نظر گرفته شد. نتایج نشان داد كه در الگوهای مختلف كاشت بیشترین میزان سدیم برگ بدون مصرف هورمون به دست آمد ولی كمترین میزان سدیم برگ با تیمار اكسین مشاهده شد. مصرف هورمون در هر سه الگوی كاشت منجر به افزایش پتاسیم بخش هوایی شد كه البته بیشترین افزایش با مصرف سیتوكینین با الگوی كاشت كف فارو (46/1 برابر بیشتر از شاهد) بدست آمد. در كاشت كف فارو مصرف هورمون میزان كلر برگ را كاهش داد و بیشترین كلر برگ بدون مصرف هورمون بدست آمد در حالی كه مصرف سیتوكینین و اكسین به ترتیب 86/6 و 24/21 درصد غلظت كلر را كاهش داد. مصرف هورمون در الگوهای مختلف كاشت كلر بخش هوایی را كاهش داد ولی بیشترین كاهش با سیتوكینین (22 درصد كاهش نسبت به شاهد) بود. به طور كلی نتایج نشان داد كه مصرف سیتوكینین و اكسین به ویژه در الگوی كاشت كف فارو موجب كاهش غلظت سدیم، كلر و نسبت سدیم به پتاسیم و افزایش غلظت پتاسیم و كلسیم گیاه شد.

Introduction: Maize (Zea mays L.) which belongs to the Poaceae family is the third important cereal crop of the world after wheat and rice. Salinity is one of the major environmental factors limiting plant growth and productivity. Maize is sensitive to salinity. Planting method is a crucial factor for improving crop yield. Planting methods in saline and non-saline conditions are different. Kinetin is one of the cytokinins known to significantly improve the growth of crop plants grown under salinity. Indole acetic acid (IAA) is also known to play a significant role in plant tolerance to salt stress. However, little information appears to be available on the relationship between salinity tolerance and auxin or cytokinin levels in plants. In this respect, the objective of this study was to study the effects of foliar application of cytokinin and auxin hormones on distribution and accumulation of chlorine and some macro elements in different parts of maize in salinity conditions. Materials and Methods: The experiment was carried out at Bushehr Agricultural and Natural Resources Research and Education Center, Dashtestan station with 29° 16´ E latitude and 51° 31´ N, longitude and 70 m above the see surface during the 2014 growing season. Dashtestan region is a warm-arid region with 250 mm precipitation per year. The field plowed inApril 2014 and then prepared and sowed inAugust 2014. There were five rows with 75 cm distance. The experiment was conducted as a split-plot design based on complete randomized blocks with three replications. Planting pattern (ridge planting, double rows of planting on a ridge in zigzag form and furrow planting) as the main factor and use of hormone (not consumption (control), application of cytokinin hormone in the time of V8-V10 and application of auxin hormone at the silking stage) was considered as the sub-factor. Cytokinin (Benzyl Adenine, Merck) and Auxin (Indole-3-Butiric Acid, Merck) were sprayed on the entire plant in the evening with concentration of 50 and 10 g. l-1, respectively. All traits measured on 10 randomly selected plants of each plot. Data analyzed using the SAS (Ver.9.1) and comparing of the means was conducted using Duncan’s multiple range test. Results and Discussion: The measured salinity of soil at a depth of 0 to 30 cm in different locations of planting patterns and in different time period showed that in different planting patterns because salt movement by capillary ascent and its accumulation in the ridges, salinity center stack was the highest and the lowest salinity belonged to the furrow planting. The highest Potassium (K+) and Calcium (Ca2+) ions were obtained with pattern of furrow planting, while the highest sodium ions (Na+), Chlorine ions (Cl-) and Na+/K+ were devoted to the pattern of conventional planting (ridge planting). Foliar application of benzyladenine (BA) and indole-3-butyric acid (IBA) sodium ions (Na+) and Na+/K+. The results showed that in all three planting pattern the most sodium leaf was obtained without the use of hormone auxin, but the lowest amount of sodium leaf was observed with auxin treatment. In each pattern, use of hormone leading to increased potassium of shoot, but the largest increase was cytokinin hormone, of course, the greatest increase was achieved by application of cytokinin hormone. In furrow planting use of hormone reduced the amount of leaf chlorine so that most leaf chlorine was obtained without the use of hormones. While, use of cytokinin and auxin hormones reduced the amount of leaf chlorine by 6.86 and 21.24 percent, respectively. Use of hormone in all planting methods reduced the amount of shoot chlorine but the greatest reduction was achieved by application of cytokinin hormone. Conclusions: In general, it can be concluded that increasing concentrations of sodium, magnesium and chlorine in leaves and shoots in row planting compared to planting two rows and furrow planting could be related to higher concentrations of these elements in the soil and in the location of the plant and as a result decrease of plant growth and therefore higher concentration of elements in various parts of the plant in the row planting. It is concluded that use of cytokinin and auxin especially in the furrow planting reduced the concentration of sodium, chloride and sodium to potassium ratio and increased plant potassium and calcium concentration.