اﺛﺮات ﺗﻌﺪﻳﻠﻲ اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ روي ﺟﻮاﻧﻪزﻧﻲ و رﺷﺪ روﻳﺸﻲ ﮔﻴﺎه ﻛﻠﺰا ﺗﺤﺖ ﺗﻨﺶ ﺷﻮري

Alleviating effects of humic acid on germination and vegetative growth of canola under salinity stress

ﺷﻮري ﺗﻨﺶ ﻏﻴﺮ زﻳﺴﺘﻲ ﻣﻮﺛﺮ ﺑﺮ ﺗﻮﻟﻴﺪ ﮔﻴﺎﻫﺎن اﺳﺖ ﻛﻪ ﺑﺎ ﻛﺎرﺑﺮد ﻣﻨﺎﺳﺐ ﻣﻮاد آﻟﻲ ﻣﻲﺗﻮان از ﺗﺒﻌﺎت آن ﻛﺎﺳﺖ. ﺑﻪ ﻫﻤﻴﻦ ﻣﻨﻈﻮر در اﻳﻦ آزﻣﺎﻳﺶ، اﺛﺮ ﺗﻌﺪﻳﻠﻲ ﺗﻴﻤﺎر اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ )ﺷﺎﻫﺪ، 500 و 1000 ﻣﻴﻠﻲ ﮔﺮم در ﻟﻴﺘﺮ( ﺑﺮ ﺗﻨﺶ ﺷﻮري )ﺷﺎﻫﺪ، 4، 8 و 12 دﺳﻲ- زﻳﻤﻨﺲ( روي ﺻﻔﺎت ﺟﻮاﻧﻪزﻧﻲ ﺑﺬر و ﺑﺮﺧﻲ از ﺧﺼﻮﺻﻴﺎت ﻓﻴﺰﻳﻮﻟﻮژﻳﻜﻲ ﮔﻴﺎه ﻛﻠﺰا در دو ﻣﺮﺣﻠﻪ ﺟﻮاﻧﻪزﻧﻲ و رﺷﺪ روﻳﺸﻲ ﺑﺮرﺳﻲ ﺷﺪ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻧﺘﺎﻳﺞ، اﺛﺮ ﺑﺎزدارﻧﺪﮔﻲ ﺗﻨﺶ ﺷﻮري روي ﺻﻔﺎت ﺟﻮاﻧﻪزﻧﻲ ﻣﻌﻨﻲدار ﺑﻮد. ﻫﻤﭽﻨﻴﻦ ﺗﻴﻤﺎر ﺷﻮري، ﻣﺤﺘﻮي ﻛﻠﺮوﻓﻴﻞ ﺑﺮگ و ﭘﺎﻳﺪاري ﻏﺸﺎ آن را ﺑﻪ ﺷﺪت ﻛﺎﻫﺶ داد. ﺗﻴﻤﺎر اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ ﺑﺎﻋﺚ اﻓﺰاﻳﺶ ﻧﺴﺒﻲ ﻣﺤﺘﻮي ﻛﻠﺮوﻓﻴﻞ a، ﻛﻠﺮوﻓﻴﻞ ﻛﻞ و ﻛﺎرﺗﻨﻮﺋﻴﺪ ﺑﺮگ ﮔﻴﺎه در ﻏﻠﻈﺖ 1000 ﻣﻴﻠﻲﮔﺮم در ﻟﻴﺘﺮ ﺷﺪ. ﻣﻌﻨﻲدار ﺷﺪن اﺛﺮ ﻣﺘﻘﺎﺑﻞ ﺗﻴﻤﺎر ﺷﻮري و اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ روي ﺻﻔﺎت ﭘﺎﻳﺪاري ﻏﺸﺎ، درﺻﺪ ﺟﻮاﻧﻪ زﻧﻲ، ﺳﺮﻋﺖ ﺟﻮاﻧﻪزﻧﻲ و ﻃﻮل رﻳﺸﻪﭼﻪ، ﺣﺎﻛﻲ از ﺗﻌﺪﻳﻞ ﺗﻨﺶ ﺷﻮري ﺗﻮﺳﻂ ﺗﻴﻤﺎر اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ در اﻳﻦ ﺻﻔﺎت ﺑﻮد، ﺑﻄﻮريﻛﻪ ﺗﻴﻤﺎر 1000 ﻣﻴﻠﻲ ﮔﺮم ﺑﺮ ﻟﻴﺘﺮ اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ ﺗﻮاﻧﺴﺖ در ﺳﻄﺢ 4 دﺳﻲ زﻳﻤﻨﺲ ﺗﻨﺶ ﺷﻮري، درﺻﺪ ﺟﻮاﻧﻪزﻧﻲ را ﺑﻬﺒﻮد دﻫﺪ. ﻫﻤﭽﻨﻴﻦ اﻳﻦ ﺗﻴﻤﺎر ﺳﺮﻋﺖ ﺟﻮاﻧﻪ زﻧﻲ را در ﺳﻄﺢ 8 دﺳﻲ زﻳﻤﻨﺲ ﺑﺮ ﻣﺘﺮ اﻓﺰاﻳﺶ داد. اﺛﺮات ﺗﻌﺪﻳﻠﻲ ﺗﻴﻤﺎر اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ ﺑﺮ ﭘﺎﻳﺪاري ﻏﺸﺎء در ﺳﻄﻮح 8 و 12 دﺳﻲ زﻳﻤﻨﺲ ﻧﻴﺰ ﻗﺎﺑﻞﺗﻮﺟﻪ ﺑﻮد. ﺑﻪ اﻳﻦ ﺗﺮﺗﻴﺐ، ﭘﻴﺸﻨﻬﺎد ﻣﻲﮔﺮدد ﺟﻬﺖ ﺗﻌﺪﻳﻞ ﺳﻄﻮح ﻣﺘﻮﺳﻂ ﺷﻮري، اﺳﻴﺪ ﻫﻴﻮﻣﻴﻚ ﺑﺼﻮرت ﺗﻴﻤﺎر ﺑﺬري ﺑﻜﺎر رود.

Salinity is an effective abiotic stress on plants production that the application of suitable organic materials reduces its consequences. Thus, in this experiment, the mitigating effects of humic acid (0, 500 and 1000 mg.l-l) on salinity (EC; 0, 4, 8 and 12 dS.m-1) was evaluated at germination and vegetative stages of canola. According to the results, inhibitory effects of salinity on seed germination, germination rate, radicle and shoot length, and dry weights of radicle and shoot were significant. Also, salinity decreased the leaves chlorophylls contents and their membrane stabilities. Humic acid treatment increased chlorophyll (chl) a, total chl and carotenoid contents at 1000 mg l-1 concentration. Regarding to significant interaction effects of humic acid and salinity on membrane stability, seed gemination, germination rate and radicle length traits, results represent a mitigating effect of humic acid on mentioned traits under salinity condition. The humic acid at 1000 mg.l-1 level alleviates seed germination percentage at EC 4 dS.m-1, as well as improved germination rate under EC 8 dS m-1. Likewise, mitigating effect of humic acid on membrane stability at EC 8 and 12 dS.m-1 was noticeable. It was concluded that, under moderate levels of salinity, application of humic acid as seed treatments is recommended to alleviate the stress effects.