ﻣﻄﺎﻟﻌﻪ ﺑﺮﺧﯽ ﭘﺎﺳﺦﻫﺎي ﻣﻮرﻓﻮﻟﻮژﯾﮑﯽ ﮔﯿﺎه اﺳﺘﻮﯾﺎ Stevia rebaudiana Bertoni ﺑﻪ اﺛﺮات اﻟﻘﺎﮔﺮ ﮐﯿﺘﻮزان در ﺷﺮاﯾﻂ ﺷﻮري

Study of some morphological properties of stevia (Stevia rebaudiana Bertoni) to chitosan elicitor under salt stress

ﺷﻮري ﺧﺎك ﯾﮑﯽ از ﻣﻬﻤﺘﺮﯾﻦ ﺗﻨﺶﻫﺎي ﻏﯿﺮ زﯾﺴﺘﯽ ﻣﯽﺑﺎﺷﺪ ﮐﻪ آﺛﺎر ﻣﻨﻔﯽ ﺑﺮ رﺷﺪ و ﺗﻮﻟﯿﺪ ﮔﯿﺎﻫﺎن از ﺟﻤﻠﻪ ﮔﯿﺎﻫﺎن ارزﺷﻤﻨﺪ داروﯾﯽ ﻧﻈﯿﺮ ﮔﯿﺎه اﺳﺘﻮﯾﺎ دارد. از اﯾﻨﺮو، ﻫﺪف از اﯾﻦ ﺗﺤﻘﯿﻖ، ارزﯾﺎﺑﯽ ﺑﺮﻫﻤﮑﻨﺶ اﻟﻘﺎﮔﺮ ﮐﯿﺘﻮزان )ﺳﻄﻮح ﻣﺨﺘﻠﻒ ﺻﻔﺮ، 0/2، 0/4 و 0/6 درﺻﺪ( و ﺷﻮري )ﺻﻔﺮ، 50، 100 و 150 ﻣﯿﻠﯽ ﻣﻮﻻر ﮐﻠﺮﯾﺪ ﺳﺪﯾﻢ( ﺑﺮ روي ﺑﺮﺧﯽ ﺻﻔﺎت ﻣﻮرﻓﻮﻟﻮژﯾﮑﯽ ﮔﯿﺎه اﺳﺘﻮﯾﺎ ﺑﻮد. اﯾﻦ آزﻣﺎﯾﺶ ﺑﻪ ﺻﻮرت ﻓﺎﮐﺘﻮرﯾﻞ در ﻗﺎﻟﺐ ﻃﺮح ﮐﺎﻣﻼ ً ﺗﺼﺎدﻓﯽ در ﺳﻪ ﺗﮑﺮار در ﮔﻠﺨﺎﻧﻪ ﻣﻮﺳﺴﻪ آﻣﻮزش ﻋﺎﻟﯽ ﺳﻨﺎ اﻧﺠﺎم ﺷﺪ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺗﺠﺰﯾﻪ وارﯾﺎﻧﺲ ﻧﺸﺎن داد ﮐﻪ ﺗﻨﺶ ﺷﻮري ﺳﺒﺐ ﮐﺎﻫﺶ ﻣﻌﻨﯽدار ﺻﻔﺎت LAR ،RLGR ،RGR ﺷﺪ، اﻣﺎ ﺗﯿﻤﺎر ﺑﺮﻫﻤﮑﻨﺶ ﮐﯿﺘﻮزان و ﺷﻮري ﺳﺒﺐ ﺑﻬﺒﻮد ﺻﻔﺎت ﻣﻮرد ﻧﻈﺮ ﮔﺮدﯾﺪ. ﺑﺮاي ﻣﺜﺎل، ﺗﯿﻤﺎرﻫﺎي )2 درﺻﺪ ﮐﯿﺘﻮزان-100 ﻣﯿﻠﯽ ﻣﻮﻻر ﺷﻮري و 4 و 6 درﺻﺪ ﮐﯿﺘﻮزان-150 ﻣﯿﻠﯽ ﻣﻮﻻر ﺷﻮري( روي LAR، )2 درﺻﺪ ﮐﯿﺘﻮزان-150 ﻣﯿﻠﯽ ﻣﻮﻻر ﺷﻮري( روي RLGR و )2 و 6 درﺻﺪ ﮐﯿﺘﻮزان-100 ﻣﯿﻠﯽ ﻣﻮﻻر ﺷﻮري( روي RGR اﻓﺰاﯾﺶ ﻣﻌﻨﯽدار را ﻧﺸﺎن دادﻧﺪ. ﺑﺮ اﺳﺎس ﯾﺎﻓﺘﻪﻫﺎي اﯾﻦ ﭘﮋوﻫﺶ ﻣﯽﺗﻮان ﭘﯿﺸﻨﻬﺎد ﮐﺮد ﮐﻪ از اﻟﻘﺎﮔﺮ ﮐﯿﺘﻮزان ﺟﻬﺖ ﺗﻘﻮﯾﺖ ﺻﻔﺎت ﻣﺨﺘﻠﻒ ﻣﻮرﻓﻮﻟﻮژﯾﮑﯽ در ﮔﯿﺎه اﺳﺘﻮﯾﺎ و ﺳﺎﯾﺮ ﮔﯿﺎﻫﺎن از اﯾﻦ ﺧﺎﻧﻮاده در ﺷﺮاﯾﻂ ﺗﻨﺶ اﺳﺘﻔﺎده ﮔﺮدد.

Salt stress is one of significant abiotic stresses which has negative effects on growth and production of important medicinal plants such as stevia. Thus the aim of this study was to evaluate the interaction of chitosan (0, 0.2, 0.4 and 0.6%) and salt (0, 50, 100 and 150 mM NaCl) on some of morphological and biochemical properties of stevia. the results of analysis of variance showed that salt stress resulted in significant decrease of plant height, leaf area content, leaf number, internode number, fresh and dry weight of root and shoot, RGR, RLGR, LAR. However, the interaction of chitosan and salt stress caused improvement in the each trait above mentioned. For instance, the treatments of (2% chitosan-100 mM NaCl/4-6% chitosan-150 mM NaCl) on LAR, (2% chitosan-150 mM NaCl) on RLGR and (2-6% chitosan-100 mM NaCl) on RGR showed significant increase. Based on the results of this project, it could be suggested that the chitosan elicitor could be used for improvement of morphological traits in stevia and other species from this family under stress condition.