معرفي ﮔﯿﺎﻫﺎن ﮔﻮﺷﺘﯽ ﻣﺘﺤﻤﻞ ﺑﻪ ﺧﺸﮑﯽ ﻣﻨﺎﺳﺐ ﺑﺮاي ﻓﻀﺎي ﺳﺒﺰ ﺷﻬﺮي

Introduction of Drought Tolerant Succulents Suitable for Urban Landscaping

ﺧﺸﮑﯽ ﯾﮑﯽ از ﻣﻬﻤﺘﺮﯾﻦ ﻋﻮاﻣﻞ ﻣﺤﯿﻄﯽ ﻣﯽﺑﺎﺷﺪ ﮐﻪ ﺣﺪاﻗﻞ 25% از ﺗﻮﻟﯿﺪﻫﺎي ﺟﻬﺎﻧﯽ را ﻣﺤﺪود ﻣﯽﺳﺎزد. ﮐﻤﯿﺖ و ﮐﯿﻔﯿﺖ رﺷﺪ ﮔﯿﺎﻫﺎن ﺑﻪ ﺗﻘﺴﯿﻢ، ﻃﻮﯾﻞ ﺷﺪن و ﺗﻤﺎﯾﺰﯾﺎﺑﯽ ﺳﻠﻮلﻫﺎ ﺑﺴﺘﮕﯽ دارد و ﺗﻤﺎم اﯾﻦ ﻋﻮاﻣﻞ ﻣﻤﮑﻦ اﺳﺖ ﺗﺤﺖ ﺗﺎﺛﯿﺮ ﺗﻨﺶ آﺑﯽ ﻗﺮار ﮔﯿﺮﻧﺪ. ﻫﻤﭽﻨﯿﻦ، ﺗﺮﮐﯿﺐﻫﺎي ﻣﺨﺘﻠﻒ ﮔﯿﺎﻫﯽ، ﺑﻪ ﺷﺪت ﺗﺤﺖ ﺗﺎﺛﯿﺮ ﺷﺮاﯾﻂ ﻣﺤﯿﻄﯽ ﻣﺨﺘﻠﻒ ﻗﺮار ﻣﯽﮔﯿﺮﻧﺪ. اﺳﺘﻔﺎده از ﮔﯿﺎﻫﺎن ﻣﻘﺎوم ﺑﻪ ﮐﻢ آﺑﯽ و ﺗﻨﺶ ﺧﺸﮑﯽ در ﻓﻀﺎي ﺳﺒﺰ در ﺑﺤﺮان ﮐﻢ آﺑﯽ ﮐﺸﻮر ﺑﺴﯿﺎر ﺣﺎﺋﺰ اﻫﻤﯿﺖ ﻣﯽﺑﺎﺷﺪ. در راﺳﺘﺎي دﺳﺘﯿﺎﺑﯽ ﺑﻪ ﻫﺪف ﻣﺬﮐﻮر، اﯾﻦ ﭘﮋوﻫﺶ در ﻣﺮﮐﺰ ﭘﮋوﻫﺸﯽ ﺑﺎغ ﮔﯿﺎﻫﺸﻨﺎﺳﯽ ارم در ﺷﯿﺮاز اﻧﺠﺎم ﮔﺮﻓﺖ ﺗﺎ درﺟﻪ ﺗﺤﻤﻞ ﮔﯿﺎﻫﺎن ﮔﻮﺷﺘﯽ Crassula portulacaria ، Echeveria affinis ،Kalanchoe laxiflora ،Echeveria elegans در ﺷﺮاﯾﻂ ﮐﻤﺒﻮد آب، ﺑﺎ اﻧﺪازهﮔﯿﺮي وﯾﮋﮔﯽﻫﺎي ﻓﯿﺰﯾﻮﻟﻮژﯾﮑﯽ و ﻣﻮرﻓﻮﻟﻮژﯾﮑﯽ )ﻣﯿﺰان ﮐﻠﺮوﻓﯿﻞ، ﻣﯿﺰان ﭘﺮوﻟﯿﻦ، ﺗﺒﺎدل ﯾﻮﻧﯽ، وزنﺗﺮ و ﺧﺸﮏ رﯾﺸﻪﻫﺎ و ﺳﺎﻗﻪﻫﺎ( ﺑﺮرﺳﯽ ﺷﻮد. ﮔﯿﺎﻫﺎن ﻫﻢ اﻧﺪازه در ﮔﻠﺪانﻫﺎي ﺑﺎ ﻗﻄﺮ 20 ﺳﺎﻧﺘﯽ ﻣﺘﺮ ﮐﺎﺷﺘﻪ ﺷﺪﻧﺪ و در ﻓﻀﺎي آزاد ﻣﺸﺎﺑﻪ ﻣﺤﻠﯽ ﮐﻪ در ﻧﻬﺎﯾﺖ در ﻓﻀﺎي ﺳﺒﺰ ﮐﺎﺷﺘﻪ ﻣﯽ-ﺷﺪﻧﺪ، ﻗﺮار داده ﺷﺪﻧﺪ. در ﻣﺪت 2 ﻣﺎه از ﮔﺮمﺗﺮﯾﻦ ﻣﺎهﻫﺎي ﺳﺎل ﯾﻌﻨﯽ ﺗﯿﺮ و ﻣﺮداد، 6 دور آﺑﯿﺎري )5، 10، 15، 20، 25 و 30 روز( ﺑﻪ ﮐﺎر ﺑﺮده ﺷﺪ ﺗﺎ وﻗﺘﯽ ﮐﻪ ﺧﺎك ﮔﯿﺎﻫﺎن ﺑﻪ ﻇﺮﻓﯿﺖ ﻣﺰرﻋﻪ رﺳﯿﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﮐﻪ ﺗﻨﺶ آﺑﯽ، وزنﺗﺮ و ﺧﺸﮏ رﯾﺸﻪ و ﺳﺎﻗﻪ را ﮐﺎﻫﺶ داد. ﻣﻘﺪار ﭘﺮوﻟﯿﻦ، ﻧﺸﺖ ﯾﻮﻧﯽ و ﻣﻘﺪار ﮐﻠﺮوﻓﯿﻞ در ﻫﻤﻪ ﮔﯿﺎﻫﺎن ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﺗﺤﺖ ﺷﺮاﯾﻂ اﯾﻦ آزﻣﺎﯾﺶ ﺑﻪ ﻃﻮر ﻣﻌﻨﯽداري اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻨﺪ. در ﻧﺘﯿﺠﻪ اﯾﻦ ﭘﮋوﻫﺶ، ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﺗﻤﺎم وﯾﮋﮔﯽﻫﺎي اﻧﺪازهﮔﯿﺮي ﺷﺪه، دور آﺑﯿﺎري 5 روزه، ﻣﻮﺟﺐ ﺑﺎﻻﺗﺮﯾﻦ ﻋﻤﻠﮑﺮد در ﮔﯿﺎﻫﺎن ﺷﺪ و ﻫﻤﻪ ﮔﯿﺎﻫﺎن ﻣﻮرد ﺑﺮرﺳﯽ ﺑﻪ ﻋﻨﻮان ﮔﯿﺎﻫﺎن ﻣﻘﺎوم ﺑﻪ ﮐﻢ آﺑﯽ ﺑﺮاي اﺳﺘﻔﺎده در ﻓﻀﺎي ﺳﺒﺰ ﺗﻮﺻﯿﻪ ﻣﯽﮔﺮدﻧﺪ.

Drought is the most important abiotic factor that limits at least 25% of production of world fields. The quantity and quality of plant growth depend on cell division, enlargement and differentiation and all of these factors may be affected by water stress. Also, different plant compounds are strongly influenced by different environmental conditions. The present study was carried out in Eram Botanical Garden Research Center to investigate the degree of drought tolerance in succulents (Crassula portulacaria, Echeveria elegans, Kalanchoe laxiflora, Echeveria affinis) by measuring morphological and physiological characters (amount of chlorophyll, proline, electrical conductivity, wet weight of shoot and root, dry weight of shoot and root) under water deficit conditions. Uniform plants were planted (in 20 cm pots) and kept at open area where they would be finally planted in landscape. Six irrigation intervals (5, 10, 15, 20, 25 and 30 days) were applied until the plant soils reached to field capacity for about 2 critical warmest months of June and July in the area. The experiment was conducted as a complete randomized block design with four replications for each treatment. Results showed that water deficit stress decreased shoot and root fresh and dry weights. Proline content, electrical conductivity and total chlorophyll content was significantly increased in all the succulents under the condition of this experiment. In conclusion, a 5 –day irrigation interval resulted in the highest growth and all of the plants in this study were recommended as drought tolerant plants for landscape design.