اثر نيترات نقره، تيمول، نانوذرات نقره سبز و كيتوزان بر عمر گلجايي گل شاخه بريدني ميخك رقم ’White Liberty‘

The Effects of Silver Nitrate, Thymol, Green Silver Nanoparticles and Chitosan on Vase Life of Carnation Cut Flowers cv. White Liberty

ميخك يكي از مهم‌ترين و پر مصرف‌ترين گل‌هاي شاخه بريدني جهان مي‌باشد. در اين پژوهش اثر كيتوزان، نانوذرات نقره سبز و اسانس تيمول در سه سطح 25 ، 50 و 100 ميلي‌گرم در ليتر در مقايسه با تركيب متداول نيترات نقره و شاهد (ساكارز 2 درصد) بر عمر گلجايي ميخك رقم "WhiteLiberty" بررسي شد. تمامي تيمارها حاوي دو درصد ساكارز بودند. گل‌هاي شاخه بريدني به مدت 24 ساعت در تيمارها قرار گرفتند و پس از آن با آب مقطر جايگزين شدند. آزمايش به‌صورت طرح به‌طور كامل تصادفي با سه تكرار انجام گرفت. صفات مورد ارزيابي شامل عمر گلجايي، وزن تر نسبي (در روزهاي 2، 3، 4، 7، 9 و 10)، ميزان جذب محلول (در روزهاي 1، 2، 3، 4، 7، 8، 9 و 10)، نشت يوني گلبرگ‌ها (روز 11) و ميزان كلروفيل برگ‌ها (در روزهاي 2، 4 و 8) بود. نتايج نشان داد كه تيمارهاي مختلف بر ميزان عمر گلجايي ميخك اثر معني‌دار دارند و به‌ترتيب تيمارهاي تيمول 25 (با 13 روز)، نانوذرات 25 (با 5/12 روز) و كيتوزان 25 (3/ 12 روز) داراي بيشترين عمر گلجايي در مقايسه با شاهد بودند. در ضمن تأثير تيمارهاي مختلف بر ميزان وزن تر نسبي و ميزان جذب آب در روزهاي مورد ارزيابي معني‌دار گرديد اما بر ميزان كلروفيل برگ‌ها معني‌دار نگرديد.

Background and Objectives Carnation (Dianthus caryophyllus) is one of the most important and consumption cut flowers in the world. Carnation cut flowers are sensitive to microbial contaminations at the stem end or in the vase solutions that make their vase life shorter. Numerous studies have reported that three genera of bacteria are the main bacteria which were recognized in the preservative solution of cut flowers. Nowadays, the finding of new compounds as alternatives to common chemicals is important in postharvest of cut flowers. The aim of this study was to investigate the effects of new compounds including chitosan, thymol and green silver nanoparticles on vase life of cut carnation flowers. Material and Methods The effects of green silver nanoparticles (25, 50 and 100 mg L-1), thymol (25, 50 and 100 mg L-1) and chitosan (25, 50 and 100 mg L-1) were investigated against of silver nitrate (25, 50 and 100 mg L-1) and control (2% sucrose) on vase life of carnation cut flowers "White Liberty", in this research. All treatments included 2% sucrose. Cut flowers were held in treatments for 24 hours, then replaced with distilled water. The experiment was carried out as completely randomized design with three replications. Evaluated characteristics were vase life, relative fresh weight (on days 2, 3, 4, 7, 9 and 10), solution uptake (on days 1, 2, 3, 4, 7, 8, 9 and 10), ion leakage of petals (on day 11) and chlorophyll contents (on days 2, 4 and 8). Results Results showed that the effects of different treatments on vase life were significant and thymol 25 (13 days), green silver nanoparticles and chitosan 25 (12.5 days) had the highest vase life in comparison with control. The effects of different treatments on relative fresh weight and solution uptake were significant in the evaluated days. Although, the chlorophyll content of leaves and ion leakage of petals were not significant. Discussions In the present study, it was found that pulse treatment by chitosan, thymol and green silver nanoparticles (25 mg L-1) significantly increased the vase life of cut carnations cv. "White Liberty". The presence of two sections of sucrose as nutrition source and antimicrobial agents seems to be necessary for carnation cut flowers. The antimicrobial effects of these compounds have been demonstrated in several studies. The application of thymol and chitosan as non-toxic compounds in the preservative solutions showed positive prospects for using these in extending carnation cut flowers.