اثر محلول‌پاشی کیتوزان بر فیزیولوژی تحمل به سرما و زمان شکفتن جوانه در انگور یاقوتی

نوع مقاله : مقاله پژوهشی

نویسندگان

• حسین صفامنش
• روح الله کریمی

گروه علوم باغبانی و فضای سبز، دانشکده کشاورزی، دانشگاه ملایر، ملایر، ایران

چکیده

کلیدواژه‌ها

• اسید آبسیزیک
• تاک
• سرمازدگی
• قند محلول
• کیتوزان
• هورمون‏ها

موضوعات

• علوم میوه

عنوان مقاله [English]

Effect of chitosan spray on cold tolerance physiology and budburst time of 'Yaghooti' grapevine

نویسندگان [English]

• Hossein Safamanesh
• Rouhollah Karimi

کلیدواژه‌ها [English]

• Abscisic acid
• Chilling injury
• Grape
• Hormones
• Soluble sugar

Extended Abstract

Introduction

Late spring cold is one of the problems of growing grapes in temperate and cold climates, which sometimes destroys up to 90% of the vineyard's yield. One of the recent methods to improve tolerance to stress in products is the use of natural molecules such as chitosan (CS), which, by stimulating the responses related to the plant's defense system, neutralizes the harmful effects of biotic and abiotic stresses and improves the yield and quality of products. Chitosan and its derivatives induce resistance of plants against abiotic stresses such as drought, salinity, high temperature and heavy metals. The aim of this research was to investigate the effect of the first season application of CS on budburst time and physiological and biochemical indices related to cold tolerance in 'Yaghooti' ​​grapes under pergola cultivation system.

Materials and methods

The present experiment was conducted in 2021 and 2022, on the own-rooted 15-year-old grapevines (V. vinifera 'Yaghooti') from a commercial vineyard with the pergola training system at Malayer in Hamadan province/Iran. The treatments included foliar application of CS at 0, 5, 10 and 20 g/L at two stages in late March and early April. Two weeks after CS spraying, the following indices such as electrolyte leakage, malondialdehyde, hydrogen peroxide, water content, proline, total phenol, total soluble carbohydrate, soluble sugars (glucose, fructose and sucrose), activity of antioxidant enzymes (catalase, ascorbate peroxidase and peroxidase), phytohormones (abscisic acid, gibberellic acid), polyamines (putrescine, spermidine and spermine) of the buds and leaf, photosynthetic pigments and also some leaf nutrients were measured in treated and control vines. Also, budburst time and bloom time were recorded and compared in different treatments.

 Results and Discussion

Based on the results, CS (10 g/L) caused a delay in the time of budburst up to 6 days later and avoided the spring cold injury of the vines. It seems that by increasing the concentration of abscisic acid, CS has made the grape buds to remain dormant and delayed their blooming in the spring season. This has protected the grape buds against the late spring cold. As the concentration of CS increased from 0 to 20 g/L, a decreasing trend was observed in the percentage of bud electrolyte leakage (EL), malondialdehyde (MDA) and hydrogen peroxidase (H₂O₂). The lowest value of these membrane damage indices was related to the buds of vines sprayed with a concentration of 20 g/L of CS. Chitosan can induce the enzyme antioxidant system and inhibit hydrogen peroxide, therby  enhancing the integrity of the membrane and improving the plant's tolerance to stress. Also, CS at 20 g/L increased abscisic acid and decreased gibberellic acid in the buds of grapevines. Furthermore, 20 g/L of CS caused a 15.16% increase in the bud water content and a 33.24% decrease in EL of the plant compared to the control. The vines sprayed with CS, particularly at concentration of 10 and 20 g/L, exhibited the highest amounts of proline, protein, carbohydrates, soluble sugars, total phenol and activity of antioxidant enzymes. In addition, the lowest accumulation of MDA content and H₂O₂ occurred in the leaves of grape in the treatment of 20 g/L CS. With the increase in CS concentration, the amount of leaf photosynthetic pigments and bud endogenous polyamines in the leaves of grapevine increased. Vines treated with 10 g/L of CS had more potassium, phosphorus and calcium content.

Conclusion

In the present study, CS spraying, especially at the concentration of 10 and 20 g/l, with an increase in the abscisic acid and a decrease in gibberellic acid contents, caused a delay in the budburst time of grapevine buds for up to 6 days. In addition, the CS foliar application increased the osmotic regulators of proline, protein, carbohydrates and soluble sugars, as well as increasing the activity of oxidizing enzymes and total phenol, leading to a decrease in MDA, H₂O₂ accumulation, and a decrease in EL percentage in vine buds, increased the cold tolerance in the grape plant through the reduction of oxygen free radicals and damage to the membrane. Therefore, CS foliar spraying, especially at a concentration of 20 g/L, can be used as a solution for cold injuries and increasing tolerance to late spring cold in grape vines. It is suggested to investigate the effect of its combination with SoluPotass on the spring cold tolerance of 'Yaghooti' grapes, considering the polysaccharide nature and emulsifiability of CS.