بررسي مراحل تكوين دانه گرده در گياه زبان گنجشك (.Fraxinus excelsiorL)

Developmental stages of the pollen grains in Ash tree (Fraxinus excelsiorL

ﮔﯿﺎه زﺑﺎن ﮔﻨﺠﺸﮏ ﺑﺎ ﻧﺎم ﻋﻠﻤﯽ Fraxinus excelsior ﻣﺘﻌﻠﻖ ﺑﻪ ﺧﺎﻧﻮاده زﯾﺘﻮن )(Oleaceae اﺳﺖ ﮐﻪ ﺑﻪ ﻃﻮر ﻣﻌﻤﻮل در ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ ﺑﯿﺸﺘﺮ اﺳﺘﺎن ﻫﺎي اﯾﺮان ﺧﺼﻮﺻﺎً اﺳﺘﺎن ﺗﻬﺮان ﻣﺸﺎﻫﺪه ﻣﯽ ﺷﻮد. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﮔﺰارش ﻫﺎي آﻟﺮژي زاﯾﯽ ﺧﺎﻧﻮاده زﯾﺘﻮن و ﻫﻤﻮﻟﻮژي ﺑﯿﻦ ﺟﻨﺲ ﻫﺎ و ﮔﻮﻧﻪ ﻫﺎي اﯾﻦ ﺗﯿﺮه و درﺻﺪ ﺑﺎﻻي ﺣﺴﺎﺳﯿﺖ ﻓﺼﻠﯽ ﺑﻪ ﮔﺮده ﻫﺎي زﺑﺎن ﮔﻨﺠﺸﮏ، ﺷﻨﺎﺧﺖ دﻗﯿﻖ داﻧﻪ ﻫﺎي ﮔﺮده اﻫﻤﯿﺖ دارد. اﻫﺪاف اﯾﻦ ﭘﮋوﻫﺶ ﺑﺮ ﻣﺒﻨﺎي ﺑﺮرﺳﯽ ﮔﺮده ﻫﺎي زﺑﺎن ﮔﻨﺠﺸﮏ ﭘﺎﯾﻪ ﻧﺮدر ﻣﺮاﺣﻞ ﻧﻤﻮي اﺳﺖ. اﺑﺘﺪا ﮔﻞ ﻫﺎ و ﻏﻨﭽﻪ ﻫﺎ در ﻣﺮاﺣﻞ ﻣﺨﺘﻠﻒ ﻧﻤﻮ ﺑﺮداﺷﺖ ﺷﺪه، در FAA70 ﺗﺜﺒﯿﺖ و ﺳﭙﺲ دراﻟﮑﻞ 70٪ ﻧﮕﻬﺪاري ﺷﺪﻧﺪ. ﻧﻤﻮﻧﻪ ﻫﺎ ﭘﺲ از آﻣﺎده ﺳﺎزي و ﻗﺎﻟﺐ ﮔﯿﺮي در ﭘﺎراﻓﯿﻦ، ﺑﺎ ﻣﯿﮑﺮوﺗﻮم ﺑﺮش ﮔﯿﺮي ﮔﺮدﯾﺪ. رﻧﮓ آﻣﯿﺰي ﺑﺎ ﭘﺮﯾﻮدﯾﻚ اﺳﯿﺪ ﺷﯿﻒ و ﻧﯿﺰ ﺑﺎ ﻫﻤﺎﺗﻮﮐﺴﯿﻠﯿﻦ اﻧﺠﺎم ﺷﺪ. ﺑﺮرﺳﯽ دﻗﯿﻖ ﺳﺎﺧﺘﺎر داﻧﻪ ﮔﺮده ﺑﺎ ﻣﯿﮑﺮوﺳﮑﭗ اﻟﮑﺘﺮوﻧﯽ ﻧﮕﺎره ﺻﻮرت ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ در اﯾﻦ ﮔﯿﺎه ﺑﺴﺎك ﻫﺎ داراي ﭼﻬﺎر ﮐﯿﺴﻪ ﮔﺮده ﺑﻮده و ﺗﮑﻮﯾﻦ ﮔﺮده ﻫﺎ در ﺑﺴﺎك ﻧﺎﻫﻤﺰﻣﺎن اﺳﺖ. داﻧﻪ ﻫﺎي ﮔﺮده در زﻣﺎن اﻧﺘﺸﺎر دو ﯾﺎﺧﺘﻪ اي، داراي ﺳﻪ ﺷﮑﺎف روﯾﺸﯽ و ﺑﺎ ﺗﺰﯾﯿﻨﺎت رﮔﻪ دار- ﺷﺒﮑﻪ اي ﺷﮑﻞ ﻫﻤﺮاه ﺑﺎ اورﺑﯿﮑﻮل ﻫﺎﯾﯽ ﺑﺎاﻧﺪازه ﻣﺘﻔﺎوت در ﺳﻄﺢ ﻣﺸﺎﻫﺪه ﻣﯽ ﺷﻮﻧﺪ. ﺗﺘﺮادﻫﺎي ﻣﯿﮑﺮوﺳﭙﻮري از ﻧﻮع ﺗﺘﺮا ﻫﺪرال )ﻫﺮﻣﯽ( و ﮐﻮﺑﯿﮏ )ﭼﻬﺎرﺿﻠﻌﯽ( اﺳﺖ. ﺳﻠﻮل ﻫﺎي ﻻﯾﻪ ﺗﺎﭘﯽ ﺑﻪ ﺻﻮرت دو ﻫﺴﺘﻪ اي درﺷﺖ ﺑﻮده و ﻫﺮ دو ﺣﺎﻟﺖ ﺗﺮﺷﺤﯽ و آﻣﯿﺒﯽ وﺟﻮد دارد. ﺷﻨﺎﺧﺖ دﻗﯿﻖ ﺳﻠﻮل- ﺑﺎﻓﺖ ﺷﻨﺎﺳﯽ داﻧﻪ ﻫﺎي ﮔﺮده ﻣﯽ ﺗﻮاﻧﺪ در ﮐﺎرﺑﺮدﻫﺎي آﺋﺮوﺑﯿﻮﻟﻮژي و ﺑﺮرﺳﯽ آﻟﺮژن ﻫﺎ ﺑﻪ اﻧﺠﺎم ﺗﺤﻘﯿﻘﺎت دﻗﯿﻖ ﺗﺮ در اﯾﻦ زﻣﯿﻨﻪ ﮐﻤﮏ ﮐﻨﺪ.

Fraxinus excelsior is a common tree belongs to the Oleaceae family which is commonly found in the vegetation of most areas of Iran, especially Tehran province. According to the reports of allergenicity of olive family and homology between genera and species of this genus and high level of seasonal sensitivity to ash pollens, accurate knowledge of pollens is essential. In this research we investigated the pollen grains developmental characteristics of pure male flowers F. excelsior. The flowers and buds, in different developmental stages, were removed, fixed in FAA70, stored in 70% ethanol, and following dehydration and embedding in paraffin, the specimens were sliced by a rotary microtome. Staining was carried out with PAS and contrasted with Hematoxylin and prepared specimens were studied under a light microscope. Also, to be observed pollen structure was examined by SEM and FESEM electron microscopy. The results indicated that consist of two stamens and anthers were four pollen sacs and pollen tetrads types were tetragonal and cubic. Pollen grains, when shed had three colpes and Striped-mesh ornaments and/or be observed along with orbicules of different sizes on the surface. The pollen grains, in this plant, are spherical in polar view and fusiform in equatorial view; mature pollens are prolate, tricolporoidate with furrows disposed along polar axis. The disposition of the microspore in the tetrads is tetrahedral. The pollen grains are 2-celled when shed. Scrutiny cell and tissue of pollen grains can help in more thorough investigation on applications of aerobiology and identification of pollen allergens.