Campsis radicans (L.) seem'ın polen ontogenezinin sitolojik ve embriyolojik yönden incelenmesi
Küçük Resim Yok
Tarih
2012
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Trakya Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada Bignoniaceae familyasına ait Campsis radicans (L). Seem'in polen ontogenezi sitolojik ve embriyolojik yönden ışık ve transmisyon elektron mikroskobu kullanılarak incelenmiştir. Campsis radicans'ın andrekeumu didinam tiptedir ve anterleri tetrasporangiattır. Anter çeperi epidermis, endotesyum, ara tabaka ve salgı tapetumundan oluşmaktadır. Tapetum hücreleri iki farklı kökenden gelen ve yapısal olarak dimorfik olan iç ve dış tapetum olmak üzere iki çeşittir. Tapetum hücrelerinde, normal mitoz bölünme, sekonder nukleus bölünmeleri ve nukleus birleşmeleri gözlenmiştir. Mayoz bölünme genelde düzenlidir. Olgun polenleri iki hücrelidir. Polen sterilitesi % 19.9 dur. Anter çeperinin epidermis ve endotesyum tabakaları anter ve polen gelişiminin sonuna kadar parçalanmadan kalır ancak ara tabaka ve tapetum tabakası polen gelişimi sırasında yok olur.Polen ontogenezi sporogen dokuda ve anter çeperi hücrelerinde oluşan değişikliklere göre sporogen hücre evresi, polen ana hücresi evresi, tedrad evresi, serbest mikrospor evresi, vakuollü mikrospor evresi ve iki hücreli polen evresi olmak üzere 6 gelişim evresine ayrılmaktadır. Sporogen hücre, PAH, mikrospor ve olgun polenin sitoplazması değişen miktarlarda çözünmeyen polisakkarit, lipid ve protein içermektedir. Polen ana hücreleri simultane tip mayoz bölünme geçirerek tetrahedral ve tedrogonal dizilimli tedradları oluşturur.Campsis radicans'ta polen duvarının oluşumu tedrad aşamasında primekzin denilen ekzin kalıbının oluşumuyla başlar. Primekzin kalıptaki özel yerlerde mikrosporlar tarafından üretilen elektron yoğun materyallerin birikmesiyle ekzin elemanlarından önce protektum daha sonra probakulalar oluşur. Serbest mikrospor aşamasından itibaren tapetum kaynaklı sporopoleninin ekzin yapısına eklenmesiyle ekzin oluşumu tamamlanır. Polen duvarının intin tabakasının oluşumu ise vakuollü mikrospor aşamasında başlayıp iki hücreli polen aşamasında devam eder.Anahtar kelimeler: Campsis radicans, Bignoniaceae, polen ontogenezi, Anter çeperi.
In this study, pollen ontogeny of Campsis radicans (L.) Seem belonging to Bignoniaceae family had been investigated in cytological and embryological respectsby using light and transmission electron microscopy methods. Campsis radicans has didynamous stamen with tetrasporangiate anthers. Its anther wall consists of epidermis, endothecium, middle layer and a secretory type of tapetum. Tapetum of Campsis radicans have two types of cells as an inner and outer tapetum which are dual in origin and dimorphic. Normal mitosis, secondary nuclear divisions and nuclear fusions had been observed in tapetum cells. Meiotic division is generally regular. Mature pollen grains are 2-celled. Pollen sterility is 19 %. Epidermis and Endothecium layers of anther wall remain intact until the end of anther and pollen development however middle layer and tapetum disappear during pollen development.Pollen ontogeny has been divided into 6 developmental stages according to the events which take place in the sporogenous tissue and and anther wall. These stages are: sporogenous cell, pollen mother cell, tedrad, free microspore, vacuolated microspore and bicellular pollen stages. Cytoplasm of sporogenous cell, pollen mother cell, microspore and mature pollen contains varying amount of insoluble polysaccharides, lipids and proteins. Microspore mother cells undergo simultaneous meiosis, forming tetrads with a tetrahedral and tedrogonal arrangement.Pollen wall formation in Campsis radicans starts at tedrad stage by the formation of exine template called primexine. By the accumulation of electron dense material produced by microspore in the special places of the primexine, first of all protektum then probacula of exine elements are formed. After free microspore stage exine development is complated by the addition of sporopollenin from tapetum. Formation of intine layer of pollen wall starts at the vacuolated stage of pollen development and continue through the bicellular pollen stage.Key words: Campsis radicans, Bignoniaceae, pollen ontogeny, anther Wall
In this study, pollen ontogeny of Campsis radicans (L.) Seem belonging to Bignoniaceae family had been investigated in cytological and embryological respectsby using light and transmission electron microscopy methods. Campsis radicans has didynamous stamen with tetrasporangiate anthers. Its anther wall consists of epidermis, endothecium, middle layer and a secretory type of tapetum. Tapetum of Campsis radicans have two types of cells as an inner and outer tapetum which are dual in origin and dimorphic. Normal mitosis, secondary nuclear divisions and nuclear fusions had been observed in tapetum cells. Meiotic division is generally regular. Mature pollen grains are 2-celled. Pollen sterility is 19 %. Epidermis and Endothecium layers of anther wall remain intact until the end of anther and pollen development however middle layer and tapetum disappear during pollen development.Pollen ontogeny has been divided into 6 developmental stages according to the events which take place in the sporogenous tissue and and anther wall. These stages are: sporogenous cell, pollen mother cell, tedrad, free microspore, vacuolated microspore and bicellular pollen stages. Cytoplasm of sporogenous cell, pollen mother cell, microspore and mature pollen contains varying amount of insoluble polysaccharides, lipids and proteins. Microspore mother cells undergo simultaneous meiosis, forming tetrads with a tetrahedral and tedrogonal arrangement.Pollen wall formation in Campsis radicans starts at tedrad stage by the formation of exine template called primexine. By the accumulation of electron dense material produced by microspore in the special places of the primexine, first of all protektum then probacula of exine elements are formed. After free microspore stage exine development is complated by the addition of sporopollenin from tapetum. Formation of intine layer of pollen wall starts at the vacuolated stage of pollen development and continue through the bicellular pollen stage.Key words: Campsis radicans, Bignoniaceae, pollen ontogeny, anther Wall
Açıklama
Doktora
Anahtar Kelimeler
Botanik, Botany
