بررسی ساختار سلولی انواع مختلف کرک در گونهboiss. salvia macrosiphon و تغییرات آن‫ها در جمعیت‫های مختلف‬‬‬‬‬‬‬‬‬‬‬‬

هدف:boiss.   salvia macrosiphon از گونه‫های معطر یک‫ساله  تیره lamiaceae است که به‫طور وسیعی در کشور ایران می‫روید. به‫دلیل وجود متابولیت‌های ثانویه، این گونه کاربرد وسیعی در طب سنتی دارد. هدف از این مطالعه، تعیین انواع مختلف کرک در سطح اپی‫درم برگ این گونه و نحوه تغییر تراکم  و نوع کرک در بین جمعیت‌های مختلف آن است. مواد و روش‌ها:  به این منظور، تعداد 8 جمعیت از این گیاه از رویشگاه های  طبیعی آن جمع آوری شده و از هر جمعیت 3 برگ سالم و بالغ انتخاب شدند. برش گیری توسط دست انجام شد و رنگ آمیزی مضاعف توسط رنگ‫های کارمن زاجی و آبی متیل صورت پذیرفت. نتایج: در سطح اپیدرم برگ گونه مورد نظر پوشش کرکی متراکمی وجود داشته که متشکل از کرک‌های غیر غده‌ای و کرک‌های غد ه‌ای است. کرک‌های غیر غده‌ای فاقد انشعاب بودند و به اشکال یک تا پنج سلولی مشاهده شدند. کرک‌های غده‌ای از نوع سردارپایه کوتاه و پایه بلند، سپری و انگشتی شکل هستند. فراوان‌ترین نوع کرک‌ها درسطح برگ همه جمعیت‌ها، کرک‌های غیر غده‌ای دو تا چهار سلولی بودند. در میان کرک‌های غده‌ای، فراوان‌ترین نوع سردار پایه کوتاه بود. نتیجه گیری: تراکم کرک‫ها در بین جمعیت‫های مورد مطالعه متفاوت بوده که نشان دهنده تطابق گیاه  با زیستگاه گیاه  و فرآیند گونه زایی است. همچنین گیاهان جمعیت هایی که دارای تراکم کرک‫های سردار پایه کوتاه بیشتری بودند نسبت به گیاهان سایر جمعیت‫ها عطر بیشتری داشتند.

investigation of trichomes cellular structure in salvia macrosiphon boiss. and their diversities among various populations

aims: salvia l. with more than 1000 taxa is the largest genus in lamiaceae family, that naturally grows in diverse regions of the world. the genus is represented in iran by about 60 species, which 17 of them are endemic for the country. salvia macrosiphon boiss., is an annual aromatic herb of this genus, which is widely distributed in diverse parts of iran. due to the presence of a wide range of secondary metabolites (especially essential oil), this plant has been widely applied in the traditional medicine to cure different diseases. various types of glandular and non-glandular trichomes have been detected in lamiaceae taxa.  essential oils are composed of several compounds, and are biosynthesized  and stored in the glandular trichomes. additionally, the non-glandular trichomes play the prominent roles in growth and development of plants.  this study was aimed to detect different types of trichomes on the leaf epidermal surface of s. macrosiphon, and their variations among different iranian populations. material and methods: eight natural populations of this plant were harvested from diverse habitats in iran. plant samples were identified, according to the morphological descriptions are available in the  valuable references. three flowering plants were selected from each population and one mature and intact leaf was obtained per individual. the leaves were fixed in fixative (f.a.a) solution for 48 h. the hand-made cuttings of leaf’s blade were double-stained with methylene blue and carmine colors. then, the thin slices of each population were examined using a light microscopy (olympus ch2, japan) at different magnifications. results: the leaf epidermal surfaces were covered by a dense indumentum, which were composed of the glandular and non-glandular trichomes. the non-glandular trichomes had the simple and unbranched structures with one to five linear-arranged cells. the non-glandular trichomes had two cell types: long and short. however, the more frequent non-glandular trichomes were the long two to four-celled types. meanwhile, in  amir kabir population,  the five-celled non-glandular trichomes also had a high density. the glandular trichomes were detected as capitate, digitate, and peltate types. two types of capiate trichomes were observed on the leaves surfaces: short-stalked and long-stalked capitate. the main difference between these types relates to the cell number of trichomes stalk. however, the short-stalked capitate trichomes were the dominant glandular type in all the populations, except for arak and mashhad populations, which had the peltate trichome as a more frequent form.  conclusion: the capitate and peltate trichomes do not have the same ability to maintain the biosynthesized essential oil in their cellular structures. the stored essential oil in the capitate trichomes seeps out through the micropores in their apical cells. since, the short-stalked capitate was the dominant form in most populations, the secretion of essential oil makes this species very fragrant. but, these plants are less fragrant in populations that have a higher number of peltate trichomes. the non-glandular hairs play a key role in protecting the plant from herbivore insects and the ultraviolet rays of the sun light. moreover, they protect the leaf epidermal surface from extreme heat and cold. the type and density of other glandular and non-glandular trichomes widely differed among the populations which explored their adaptive importance in this species.