ﺑﺮرﺳﯽ اﺛﺮ ﻣﻼﺗﻮﻧﯿﻦ ﺑﺮ ﺧﺼﻮﺻﯿﺎت رﺷﺪ، ﻓﯿﺰﯾﻮﻟﻮژي و ﺑﯿﻮﺷﯿﻤﯿﺎﯾﯽ ﮔﯿﺎه اﺳﺘﻮﯾﺎ ﺗﺤﺖ ﺷﺮاﯾﻂ ﺗﻨﺶ ﺷﻮري

Effect of Melatonin Tretment on Growth and Physiologycal and Biochemical Characteristics of Stevia rebaudiana Berton under Salt Stress Conditions

ﺑﻪﻣﻨﻈﻮر ﺑﺮرﺳﯽ اﺛﺮ ﻣﻼﺗﻮﻧﯿﻦ ﺑﺮ ﺻﻔﺎت ﻣﻮرﻓﻮﻟﻮژﯾﮑﯽ، ﻓﯿﺰﯾﻮﻟﻮژﯾﮑﯽ و ﺑﯿﻮﺷﯿﻤﯿﺎﯾﯽ ﮔﯿﺎه اﺳﺘﻮﯾﺎ ﺗﺤﺖ ﺷﺮاﯾﻂ ﺗﻨﺶ ﺷﻮري، آزﻣﺎﯾﺸﯽ ﮔﻠﺪاﻧﯽ ﺑﻪﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﮐﺎﻣﻼً ﺗﺼﺎدﻓﯽ ﺑﺎ ﺳﻪ ﺗﮑﺮار در ﮔﻠﺨﺎﻧﻪ ﭘﮋوﻫﺸﯽ داﻧﺸﮑﺪه ﮐﺸﺎورزي داﻧﺸﮕﺎه ﻣﺤﻘﻖ اردﺑﯿﻠﯽ در ﺳﺎل 1398 اﺟﺮا ﺷﺪ. ﺗﯿﻤﺎرﻫﺎي آزﻣﺎﯾﺶ ﺷﺎﻣﻞ ﺗﻨﺶ ﺷﻮري در ﺳﻪ ﺳﻄﺢ )ﺻﻔﺮ، 50 و 100 ﻣﯿﻠﯽﻣﻮﻻر ﮐﻠﺮﯾﺪ ﺳﺪﯾﻢ( و ﻣﺤﻠﻮلﭘﺎﺷﯽ ﻣﻼﺗﻮﻧﯿﻦ در ﺳﻪ ﺳﻄﺢ ﺻﻔﺮ، 150 ،75 ﻣﯿﮑﺮوﻣﻮﻻر( ﺑﻮدﻧﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻣﯿﺰان ﺗﻨﺶ ﺷﻮري ﺻﻔﺎت روﯾﺸﯽ ﮔﯿﺎه از ﻗﺒﯿﻞ ﻃﻮل ﺳﺎﻗﻪ، وزن ﺧﺸﮏ ﺑﻮﺗﻪ و وزن ﺧﺸﮏ ﺳﺎﻗﻪ ﮐﺎﻫﺶ ﻣﻌﻨﯽداري ﻧﺸﺎن دادﻧﺪ. ﻣﺤﻠﻮلﭘﺎﺷﯽ ﻣﻼﺗﻮﻧﯿﻦ ﺗﺤﺖ ﺷﺮاﯾﻂ ﺗﻨﺶ ﺷﺪﯾﺪ ﺷﻮري، ﺳﺒﺐ ﺑﻬﺒﻮد اﯾﻦ ﺻﻔﺎت ﻧﺴﺒﺖ ﺑﻪ ﻋﺪم ﻣﺤﻠﻮلﭘﺎﺷﯽ ﮔﺮدﯾﺪ. ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﮐﻠﺮوﻓﯿﻞ a، ﮐﻠﺮوﻓﯿﻞ ﮐﻞ و ﮐﺎروﺗﻨﻮﺋﯿﺪ ﺑﻪﺗﺮﺗﯿﺐ ﺑﻪﻣﯿﺰان 6/64 و 7/46 و 6/24 ﻣﯿﻠﯽﮔﺮم در ﮔﺮم وزن ﺗﺮ ﺑﺮگ در ﮔﯿﺎﻫﺎن ﺗﺤﺖ ﺷﺮاﯾﻂ ﻋﺪم ﺗﻨﺶ ﺷﻮري و ﻣﺤﻠﻮلﭘﺎﺷﯽ 150 ﻣﯿﮑﺮوﻣﻮﻻر ﻣﻼﺗﻮﻧﯿﻦ ﺑﻪدﺳﺖ آﻣﺪ. ﻫﻤﭽﻨﯿﻦ ﺑﯿﺸﺘﺮﯾﻦ ﻣﻘﺪار رﻃﻮﺑﺖ ﻧﺴﺒﯽ در ﺷﺮاﯾﻂ ﻋﺪم ﺗﻨﺶ ﺷﻮري و ﮐﺎرﺑﺮد 150 ﻣﯿﮑﺮوﻣﻮﻻر ﻣﻼﺗﻮﻧﯿﻦ ﺣﺎﺻﻞ ﺷﺪ. ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﻓﻌﺎﻟﯿﺖ آﻧﺘﯽاﮐﺴﯿﺪاﻧﯽ )2/80 درﺻﺪ(، ﭘﺮاﮐﺴﯿﺪاز )0/419 واﺣﺪ در ﻣﯿﻠﯽﮔﺮم ﭘﺮوﺗﺌﯿﻦ در دﻗﯿﻘﻪ(، ﭘﺮوﻟﯿﻦ )0/49 ﻣﯿﮑﺮوﻣﻮل در ﮔﺮم وزن ﺧﺸﮏ( و ﮐﺮﺑﻮﻫﯿﺪرات ﮐﻞ )92/65 ﻣﯿﻠﯽﮔﺮم درﮔﺮم وزن ﺗﺮ( ﺗﺤﺖ ﺗﻨﺶ ﺷﻮري 100 ﻣﯿﻠﯽﻣﻮﻻر و ﮐﺎرﺑﺮد 150 ﻣﯿﮑﺮوﻣﻮﻻر ﻣﻼﺗﻮﻧﯿﻦ ﺑﻪدﺳﺖ آﻣﺪ. در ﺣﺎﻟﯽﮐﻪ ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﻓﻌﺎﻟﯿﺖ آﻧﺰﯾﻢ ﮐﺎﺗﺎﻻز )9/57 واﺣﺪ در ﻣﯿﻠﯽﮔﺮم ﭘﺮوﺗﺌﯿﻦ در دﻗﯿﻘﻪ( در ﺷﻮري 100 ﻣﯿﻠﯽﻣﻮﻻر و 75 ﻣﯿﮑﺮوﻣﻮﻻر ﻣﻼﺗﻮﻧﯿﻦ ﻣﺸﺎﻫﺪه ﮔﺮدﯾﺪ. ﺑﺎﻻﺗﺮﯾﻦ ﻣﯿﺰان ﻧﺸﺖ اﻟﮑﺘﺮوﻟﯿﺖ ﺑﺮگ ﻧﯿﺰ در ﺷﻮري 100 ﻣﯿﻠﯽﻣﻮﻻر و ﻋﺪم ﮐﺎرﺑﺮد ﻣﻼﺗﻮﻧﯿﻦ ﻣﺸﺎﻫﺪه ﺷﺪ. ﺑﻪﻧﻈﺮ ﻣﯽرﺳﺪ ﮐﻪ ﻣﺼﺮف ﻣﻼﺗﻮﻧﯿﻦ در ﺷﺮاﯾﻂ ﺗﻨﺶ ﺷﻮري ﻣﯽﺗﻮاﻧﺪ ﺑﺎﻋﺚ اﻓﺰاﯾﺶ رﺷﺪ ﮔﯿﺎه و ﺑﻬﺒﻮد ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﻮﻟﻮژﯾﮑﯽ و ﺑﯿﻮﺷﯿﻤﯿﺎﯾﯽ ﮔﯿﺎه اﺳﺘﻮﯾﺎ ﺷﻮد.

Salinity is one of the most important environmental stresses that reduced the growth, development and production of plants around the world. Stevia is a perennial herbaceous plant of the Asteraceae family. Stevia has a strong sweetening effect due to stoviol glycosides. Since the germination of stevia is poor and the seedling growth rate is slow and slow in the early stages, its evaluation to salinity stress is of special importance. Due to the increasing demand for the use of cultivars with better relative tolerance to non-living environmental stresses is increasing day by day. Also, the desirable properties of stevia for the health of the community and its sweetening and antidiabetic properties were selected for study; due to the different roles of melatonin in the plant, this study was used to investigate its effect on the growth, physiological, morphological and biochemical traits of stevia under salinity stresst. 2. Materials and Methods: In order to investigate effects of melatonin application on growth and physiology and biochemical in salinity stress in Stevia herb, a pot factorial experiment based on completely randomized design with three replications was conducted in the research greenhouse of Agriculture Faculty, Mohaghegh University of Ardebily in 2019. Treatments were consisted of salinity stress at three levels (0, 50 and 100 mM) as the first factor and the application melatonin of at three levels (0, 75, 150 μM) as the second factor. 3. Results and Discussion: Vegetative traits such as stem length, plant dry weight and stem dry weight, were significantly decreased with increasing salinity stress. Foliar spraying melatonin at high levels of salinity stress improved these traits compared to control plants. Also, the highest chlorophyll a, total chlorphyll and carotenoids content was obtained in control plants (non-salinity stress) with foliar spraying melatonin 150 μM which were 6.64 and 7.46 and 6.24 mg g-1 FW, respectively. The highest antioxidant activity (2.80%), total peroxidaz 0.419 U mg-1 protein min-1) and proline (0.49 mg g-1 DW) and Carbohidrat (92.65 mg g-1 FW) was observed in 100 mM salinity stress treatment and application 150 μM melatonin. But catalase (9.57 U mg-1 protein min-1) in 100 mM salinity stress treatment and application 75 μM melatonin was obtained. The highest relative water content (RWC) was obtained under non salinity stress conditions (control) and application of 150 μM melatonin, Then salinity stress cause decrease this quality but application melatonin cause improve this quality. Maximum level electrolyt leakage leaves also was observed in 100 mM salinity stress treatment and not application melatonin. Decreased vegetative growth due to salinity treatment is probably due to reduced photosynthetic levels as well as reduced photosynthetic pigments such as chlorophyll a and b, net carbon uptake, stomatal conduction and pore closure due to salinity stress salinity and melatonin stress significantly increased the antioxidant activity of stevia leaves. According to the results of this study, it can be said that stevia is a plant sensitive to salinity stress. As increasing salinity stress levels, a significant decrease in growth indices and photosynthetic pigments is seen. The use of melatonin improved these traits under salinity stress. Increasing the amount of melatonin compensated for the damage to the plant. As the biochemical and physiological properties of the plant such as antioxidant activity, the amount of proline, total carbohydrates improved and ultimately increased plant growth; therefore, it can be stated that melatonin consumption can increase the morphological, physiological and biochemical traits of stevia under salinity stress. The results of this study showed that salinity reduces and impairs plant growth and the use of melatonin can reduce the destructive effects of salinity to some extent and increase plant tolerance to salinity. 4. Conclusion: Overall, since most nutrient treatments, especially supernitroplas, showed superiority in many traits over both controls (application of NPKS fertilizer and no fertilizer application), replacing biofertilizers with chemical fertilizers is highly recommended.