بررسی پاسخ اکوفیزیولوژیکی گیاهان پیوندی و غیرپیوندی دو توده طالبی و گرمک ایرانی در شرایط تنش شوری

به‌منظور ارزیابی اثرات پایه بر تحمل به شوری توده‌های گرمک و سمسوری بر اساس شاخص‌های اکوفیزیولوژیکی، گیاهان غیرپیوندی و پیوندی سمسوری و گرمک روی پایه‌های تجاری ʼفرروʽ، ʼشینتوزاʽ و ʼارگوʽ و توده محلی کدو قلیانی تحت تیمار شوری (صفر، 20 و 40 میلی‌مولار کلرید سدیم) قرار گرفتند. نتایج نشان داد که در تیمارهای شوری گیاهان پیوندی نسبت به گیاهان غیرپیوندی در صفات مورد بررسی برتری داشتند. همچنین بین پایه‌های آزمون‌شده تفاوت مشاهده شد، به‌گونه‌ای که هیبرید ʼارگوʽ نسبت به دیگر پایه‌ها در بیشتر ویژگی‌های ارزیابی‌شده ضعیف‌تر بود. طبق نتایج، تنش شوری میزان پرولین و کاروتنوئید برگ را افزایش داد، این افزایش در گیاهان پیوندی کمتر از غیرپیوندی‌ها بود. همچنین میزان کلروفیل کل و محتوای نسبی آب برگ کاهش یافت که در گیاهان غیرپیوندی این کاهش بیشتر بود. با افزایش شوری پتانسیل فشار آوندی کاهش یافت. این مقدار در گیاهان غیرپیوندی نسبت ‌به گیاهان پیوندشده روی هیبرید ʼفرروʽ و کدوقلیانی کمتر بود. در توده گرمک افزایش شوری در هیچ‌یک از پایه‌های ʼفرروʽ، ʼکدو قلیانیʽ و ʼشینتوزاʽ تفاوت معنی‌داری در شاخص کارآیی فتوسنتزی ایجاد نکرد اما در گیاهان پیوندشده روی هیبرید ʼارگوʽ کمترین میزان این شاخص در سطح شوری 20 میلی‌مولار مشاهده شد. با افزایش شوری میزان قندهای محلول گیاهان پیوند شده روی هیبرید ʼفرروʽ و کدو قلیانی کاهش یافت ولی در گیاهان پیوند شده روی هیبرید ʼشینتوزاʽ افزایش شوری میزان قندهای محلول را افزایش داد. براساس یافته‌های پژوهش حاضر پایه‌های ʼفرروʽ و ʼشینتوزاʽ در ترکیب با توده‌های گرمک و سمسوری به شوری تحمل بیشتری نشان دادند.

Investigation on Ecophysiological Responses of Grafted and Nongrafted Plants in Two Iranian Melon Accessions under Salinity Stress

Introduction: Varieties of melons have long been the most important crops in Iran and have a special place in Iran 's agricultural economy which is the third major producers in the world. Different types of melons belong to various botanical groups of Cucumis melo. Salinity stress is one of the limiting factors in the production of crops. Majority lands in Iran have arid and semiarid conditions. The characteristics of these regions are high evaporation and low rainfall, which causes the accumulation of different salts in the surface layer of the earth. Salinity is one of the most important issues in the world, and millions of tons of salt are come annually from irrigation water into agricultural land. Therefore, many plants are encountered to saline soils. Grafting is developing as a new and effective way to increase the tolerance of plants to salinity in advanced countries. Several reports indicate that the rootstock type has a significant role in the resistance of the scion to environmental stresses. In the present study, salinity tolerance of two Iranian melon accessions (‘Garmak’ and ‘Samsouri’) were investigated based on ecophysiological traits, on three commercial rootstocks and a local variety of cucurbit, as well as comparing them with nongrafting plant of ‘Garmak’ and ‘Samsouri’,.;Materials and Methods: This experiment was conducted as factorial in a completely randomized design with three factors including salinity stress (in three levels) and four rootstocks and two scions with three replications in greenhouse and field of the faculty of agriculture, ValieAsr University of Rafsanjan, Iran. In this study, two melon accessions (‘Garmak’ and ‘Samsouri’) were grafted on commercial hybrids rootstocks (‘Ferro’, ‘Shintozwa’ and ‘Ergo’) and a local variety of bottle gourd and subjected to salinity treatments (0, 20 and 40 mM levels of sodium chloride) in the field. One month after adaptation of grafted plants, grafted and nongrafted plants were transferred to the field and salinity treatment (sodium chloride) was applied one week after planting in the field. The evaluated traits at the end of the experiment were: photosynthetic parameters (total chlorophyll, total carotenoids, photosynthetic efficiency index), relative water content, vascular pressure potential, proline and soluble sugars.;Results and Discussion: The results showed that in salinity treatments, grafted plants were superior to nongrafted plants in studied traits. Differences were also observed between the tested rootstocks, so that the ‘Ergo’ hybrid was weaker in many features than other rootstocks and even nongrafted plants. The results showed that salinity increased the amount of proline and carotenoids in the leaf, which was lower in grafted than nongrafted plants. With increasing salinity, the pressure of vascular pressure decreased. This amount was lower in nongrafted than in plants grafted on ‘Ferro’ and ‘bottle gourd’. Also, the total chlorophyll content and relative water content of leaf decreased, which this reduction was higher in nongrafted plants. Among the traits mentioned, the best studied rootstocks were ‘Ferro’ and ‘Shintozwa’ that were better than other rootstocks as well as nongrafted plants. By increasing salinity, the soluble sugars of grafted plants on ‘Ferro’ and ‘bottle gourd’ decreased, but in grafted plants on ‘Shintozwa’ hybrid, increased salinity increased the soluble sugars content.;Conclusions The results of this study showed that salinity stress significantly reduced the relative water content of leaves, photosynthetic pigments and carotenoids. Salinity also increased the potency of vascular pressure potential and proline concentration. Compared to nongrafted plants, the negative effects of salinity stress on nongrafted plants were more prominent than grafted plants. Also, the amount of photosynthetic parameters in grafted plants decreased less than nongrafted plants. Comparing the two evaluated accessions, ‘Samsouri’ was more appropriate than stress conditions. Compared to nongrafted and grafted plants in nonstress conditions, the best rootstock was ‘Ferro’, which showed the best result for all traits except for proline content in both ‘Samsouri’ and ‘Garmak’. At a salinity level of 40 mM, the ‘Ferro’ and ‘Shintozwa’ were superior to other rootstocks, which showed satisfactory results in most traits. Also, due to the poor reaction of the grafted plants on the bottle gourd rootstock under salt stress conditions, it seems that this rootstock probably due to low compatibility is not a suitable rootstock for two evaluated accessions in the present study. Based on the findings of the present study, ‘Ferrero’ and Shintozwa’ in combination with ‘Samsouri’ and ‘Garmak’ showed more tolerance to salinity.