تغييرات سيستم هاي پاداكساينده در انواع برگ هاي رنگي شمشاد طلايي (Euonymus japonicus Thunb.)

Changes of antioxidative systems in various color leaves of Japanese spindle (Euonymus japonicus Thunb.)

ﺑﺮﺧﯽ ﻧﺸﺎﻧﮕﺮﻫﺎي ﻓﯿﺰﯾﻮﻟﻮژﯾﮑﯽ و ﭘﺎﺳﺦ ﻫﺎي آﻧﺘﯽ اﮐﺴﯿﺪان در اﻧﻮاع ﺑﺮگ ﻫﺎي رﻧﮕﯽ درﺧﺘﭽﻪ ﺰﯾﻨﺘﯽ ﻫﻤﯿﺸﻪ ﺳﺒﺰ ﺷﻤﺸﺎد ﻃﻼﯾﯽ (.Euonymus japonicus Thunb) ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﮔﺮﻓﺖ. اﯾﻦ درﺧﺘﭽﻪ داراي ﺳﻪ ﻧﻮع ﺑﺮگ ﺑﻪ رﻧﮓ ﻫﺎي ﺳﺒﺰ ﺗﯿﺮه، ﺳﺒﺰ روﺷﻦ و زرد ﻣﯽ ﺑﺎﺷﺪ. در اﯾﻦ ﺳﻪ ﻧﻮع ﺑﺮگ ﻧﺸﺎﻧﮕﺮﻫﺎي ﺗﻨﺶ اﮐﺴﯿﺪاﺗﯿﻮ (ﻏﻠﻈﺖ ﭘﺮاﮐﺴﯿﺪ ﻫﯿﺪروژن، ﭘﺎﯾﺪاري ﻏﺸﺎﻫﺎي ﺳﻠﻮﻟﯽ و ﭘﺮاﮐﺴﯿﺪاﺳﯿﻮن ﭼﺮﺑﯽ ﻫﺎ)، ﻓﻌﺎﻟﯿﺖ آﻧﺰﯾﻢ ﭘﺮاﮐﺴﯿﺪاز و ﺑﺮﺧﯽ ﺗﺮﮐﯿﺒﺎت آﻧﺘﯽاﮐﺴﯿﺪان (ﺗﺮﮐﯿﺒﺎت ﻓﻨﻠﯽ، ﭘﺮوﻟﯿﻦ و اﺳﯿﺪﻫﺎي آﻣﯿﻨﻪ آزاد) ﻣﻄﺎﻟﻌﻪ ﺷﺪﻧﺪ. ﻧﻮع ﺑﺮگ ﺑﺮ ﻣﺤﺘﻮاي ﭘﺮاﮐﺴﯿﺪ ﻫﯿﺪروژن، ﻣﯿﺰان ﭘﺎﯾﺪاري ﻏﺸﺎﻫﺎي ﺳﻠﻮﻟﯽ و ﭘﺮاﮐﺴﯿﺪاﺳﯿﻮن ﭼﺮﺑﯽ ﻫﺎي ﻏﺸﺎﯾﯽ ﺗﺎﺛﯿﺮ ﻣﻌﻨﯽ دار ﮔﺬاﺷﺖ. ﻣﻘﺪار اﺳﯿﺪﻫﺎي آﻣﯿﻨﻪ آزاد و ﭘﺮوﻟﯿﻦ در ﺑﺮگ ﻫﺎي زرد ﺑﻪ ﺷﮑﻞ ﻣﻌﻨﯽ داري از ﺑﺮگ ﻫﺎي ﺳﺒﺰ ﺗﯿﺮه و روﺷﻦ ﺑﯿﺸﺘﺮ ﺑﻮد. ﺑﯿﺸﺘﺮﯾﻦ و ﮐﻤﺘﺮﯾﻦ ﻣﻘﺪار ﺗﺮﮐﯿﺒﺎت ﻓﻨﻮﻟﯽ آزاد ﺑﻪ ﺗﺮﺗﯿﺐ در ﺑﺮگ ﻫﺎي ﺳﺒﺰ ﺗﯿﺮه و زرد وﺟﻮد داﺷﺖ. ﯾﮏ اﻟﮕﻮي اﻓﺰاﯾﺶ ﻓﻌﺎﻟﯿﺖ آﻧﺰﯾﻢ ﭘﺮاﮐﺴﯿﺪاز در ﺑﺮگ ﻫﺎي ﺳﺒﺰ روﺷﻦ ﻧﺴﺒﺖ ﺑﻪ ﺳﺒﺰ ﺗﯿﺮه و ﺑﺮگ ﻫﺎي زرد ﻧﺴﺒﺖ ﺑﻪ ﺑﺮگ ﻫﺎي ﺳﺒﺰ روﺷﻦ ﻣﺸﺎﻫﺪه ﺷﺪ. از داده ﻫﺎي ﺣﺎﺿﺮ ﻣﯽ ﺗﻮان ﻧﺘﯿﺠﻪ ﮔﺮﻓﺖ ﮐﻪ ﺑﺎ وﺟﻮد ﻓﻌﺎﻟﯿﺖ ﺳﯿﺴﺘﻢ ﻫﺎي آﻧﺘﯽ اﮐﺴﯿﺪان، ﺗﻐﯿﯿﺮ رﻧﮓ ﺑﺮگ ﻫﺎ از ﺳﺒﺰ ﺗﯿﺮه ﺗﺎ زرد ﻣﻨﺠﺮ ﺑﻪ اﻓﺰاﯾﺶ آﺳﯿﺐ ﻫﺎي اﮐﺴﯿﺪاﺗﯿﻮ ﻣﯽ ﺷﻮد.

Some physiological parameters and antioxidant responses were investigated in different color leaves of the evergreen shrub Japanese spindle (Euonymus japonica Thunb.). The shrub has leaves with three colors including dark green, light green, and yellow. Oxidative stress markers (hydrogen peroxide concentration, cell membrane stability, and lipids peroxidation), activity of peroxidase and some antioxidant molecules (phenolic compounds, proline, and free amino acids) were studied. Significant differences were found in hydrogen peroxide content, cell membrane stability, and membrane lipids peroxidation among leaves. In yellow leaves, the total content of proline and free amino acids were higher than those of the dark green and light green leaves. The highest and lowest free phenolic compounds contents were found in the dark green and yellow leaves, respectively. The POD activity increased significantly with changing leaf color from dark green to light green and to yellow. As a result, despite the activity of the antioxidant systems, the color change from dark green to yellow caused a gradual increase in the oxidative damage.