اثر برازينواستروئيد بر صفات مرفولوژيك و فيزيولوژيك آويشن باغي (Thymus vulgaris) تحت تنش شوري

Effect of brasinosteroid on morphological and physiological traits of garden thyme (Thymusvulgaris) in salinity stress

ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺑﺎ ﻫﺪف ﮐﺎﻫﺶ اﺛﺮات ﺗﻨﺶ ﺷﻮري ﺑﺮ ﺟﻮاﻧﻪزﻧﯽ و ﻣﺮاﺣﻞ اوﻟﯿﻪ رﺷﺪ ﮔﯿﺎه داروﯾﯽ آوﯾﺸﻦ ﺑﺎﻏﯽ ﺑﺎ اﺳﺘﻔﺎده از ﮐﺎرﺑﺮد ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ در ﺷﺮاﯾﻂ ﮐﺸﺖ درونﺷﯿﺸﻪاي اﻧﺠﺎم ﺷﺪ. ﺑﺬرﻫﺎي آوﯾﺸﻦ ﺑﺎﻏﯽ در ﻣﻌﺮض ﺗﯿﻤﺎر ﺷﻮري )ﺻﻔﺮ، 50، 100 و 200 ﻣﯿﻠﯽﻣﻮﻻر( و ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ )0/5، 1 و 3 ﻣﯿﮑﺮوﻣﻮﻻر( ﻗﺮار ﮔﺮﻓﺘﻨﺪ، و ﺳﭙﺲ ﺷﺎﺧﺺﻫﺎي ﮔﻮﻧﺎﮔﻮن ﺟﻮاﻧﻪزﻧﯽ و رﺷﺪ و ﻧﯿﺰ ﺑﺮﺧﯽ وﯾﮋﮔﯽﻫﺎي ﻓﯿﺘﻮﺷﯿﻤﯿﺎﯾﯽ در ﮔﯿﺎﻫﭽﻪﻫﺎ اﻧﺪازهﮔﯿﺮي ﺷﺪﻧﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ در ﺷﺮاﯾﻂ ﺷﻮري، ﺑﯿﺶﺗﺮﯾﻦ ﻣﯿﺰان درﺻﺪ ﺟﻮاﻧﻪزﻧﯽ )95 درﺻﺪ( در ﭘﺎﯾﯿﻦﺗﺮﯾﻦ ﻏﻠﻈﺖ ﻧﻤﮏ )50 ﻣﯿﻠﯽﻣﻮﻻر( و ﺑﺎﻻﺗﺮﯾﻦ ﻏﻠﻈﺖ ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ )3 ﻣﯿﮑﺮوﻣﻮﻻر( ﻣﺸﺎﻫﺪه ﺷﺪ. ﮐﺎرﺑﺮد ﻏﻠﻈﺖﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ ﺑﺎﻋﺚ ﺑﻬﺒﻮد ارﺗﻔﺎع رﯾﺸﻪ و ﺳﺎﻗﻪ و ﻧﯿﺰ اﻓﺰاﯾﺶ ﻣﯿﺰان وزن ﺧﺸﮏ و ﺗﺮ ﮔﯿﺎﻫﭽﻪﻫﺎي آوﯾﺸﻦ ﺑﺎﻏﯽ ﺷﺪ، ﺑﻪﻃﻮريﮐﻪ در ﺷﻮري 200 ﻣﯿﻠﯽﻣﻮﻻر، ﻣﯿﺰان ﻃﻮل رﯾﺸﻪ و ﺳﺎﻗﻪ در ﻧﻤﻮﻧﻪﻫﺎي ﺗﯿﻤﺎرﺷﺪه ﺑﺎ 3 ﻣﯿﮑﺮوﻣﻮﻻر ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ ﻧﺴﺒﺖ ﺑﻪ ﻧﻤﻮﻧﻪﻫﺎي ﺗﯿﻤﺎرﺷﺪه ﺑﺎ 0/5 ﻣﯿﮑﺮوﻣﻮﻻر ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ ﺑﻪﺗﺮﺗﯿﺐ ﺣﺪود 30/5 و 42/9 درﺻﺪ اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻨﺪ. ﻣﯿﺰان ﭘﺮوﻟﯿﻦ و آﻧﺰﯾﻢﻫﺎي آﻧﺘﯽاﮐﺴﯿﺪاﻧﺖ ﭘﺮاﮐﺴﯿﺪاز )POD( و ﺳﻮﭘﺮاﮐﺴﯿﺪدﯾﺴﻤﻮﺗﺎز )SOD( در ﮔﯿﺎﻫﭽﻪﻫﺎي ﺗﯿﻤﺎرﺷﺪه ﺑﺎ ﻏﻠﻈﺖ ﺑﺎﻻﺗﺮ ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ ﻧﺴﺒﺖ ﺑﻪ ﻏﻠﻈﺖﻫﺎي ﭘﺎﯾﯿﻦﺗﺮ ﺑﻪﻃﻮر ﻣﻌﻨﯽداري اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻨﺪ و اﯾﻦ ﮔﯿﺎﻫﭽﻪﻫﺎ ﻧﻔﻮذﭘﺬﯾﺮي ﻏﺸﺎي )ﭘﺮاﮐﺴﯿﺪهﺷﺪن ﻟﯿﭙﯿﺪ( ﮐﻢﺗﺮي داﺷﺘﻨﺪ. ﻧﺘﺎﯾﺞ ﺿﺮﯾﺐ ﻫﻤﺒﺴﺘﮕﯽ ﻧﺸﺎن داد ﮐﻪ ﺑﯿﻦ ﻧﻔﻮذﭘﺬﯾﺮي ﻏﺸﺎي ﯾﺎﺧﺘﻪ )ﭘﺮاﮐﺴﯿﺪهﺷﺪن ﻟﯿﭙﯿﺪ( و ﻫﻤﻪ ﺻﻔﺎت ﺑﯿﻮﺷﯿﻤﯿﺎﯾﯽ و ﻣﺮﻓﻮﻟﻮژﯾﮏ اﻧﺪازهﮔﯿﺮيﺷﺪه ﻣﺮﺑﻮط ﺑﻪ رﺷﺪ ﮔﯿﺎﻫﭽﻪ ﻫﻤﺒﺴﺘﮕﯽ ﻣﻨﻔﯽ وﺟﻮد دارد. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ اﯾﻦ ﭘﮋوﻫﺶ، ﮐﺎرﺑﺮد ﺑﺮازﯾﻨﻮاﺳﺘﺮوﺋﯿﺪ ﺑﺎ ﻏﻠﻈﺖ 3 ﻣﯿﮑﺮوﻣﻮﻻر در ﻣﺮﺣﻠﻪ ﺣﺴﺎس ﺟﻮاﻧﻪزﻧﯽ ﺑﺬر و رﺷﺪ اوﻟﯿﻪ ﮔﯿﺎﻫﭽﻪﻫﺎي آوﯾﺸﻦ ﺑﺎﻏﯽ ﺗﺤﺖ ﺗﻨﺶ ﺷﻮري ﭘﯿﺸﻨﻬﺎد ﻣﯽﺷﻮد.

The present study was conducted to reduce the effects of salinity stress on germination and initial growth stages of Thymus vulgaris as a medicinal plant using brassinosteroid (BR) under in vitro culture. Thyme seeds were exposed to different concentrations of salinity (0, 50, 100 and 200 mM) and BR (0.5, 1 and 3 µM), and then different germination and growth indices as well as some phytochemical properties of seedlings were measured. Results indicated that under salinity conditions, the highest germination percentage (95%) was observed at the lowest salt concentration (50 mM) and the highest BR concentration (3 µM). Applying differentBR concentrations improved root and shoot height.It also increased dry and fresh biomass of thyme seedlings in a way that at the same salinity conditions of 200 mM, root and stem length increased about 30.5% and 42.9%, respectively, in samples treated with 3 µM BR in coparison with the ones treated with 0.5 µM BR. The amount of proline and antioxidant enzymes, peroxidase (POD) and superoxide dismutase (SOD) significantly increased in the seedlings treated with the highest BR concentration in comparison with those treated with the lower concentrations, and the seedlings had lower membrane permeability (lipid peroxidation). The results of correlation coefficient showed that there was a negative correlation between cell membrane permeability (amount of malondialdehyde) and all measured biochemical and morphological traits related to seedling growth. According to the results of this study, it is suggested to apply BR during the sensitive stage of seed germination and early growth of garden thyme seedlings under water or soil salinity conditions.