| عنوان فارسی مقاله: | عملکرد و تکامل تار کشنده و جذب املاح در گیاه |
| عنوان انگلیسی مقاله: | Through form to function: root hair development and nutrient uptake |
| دانلود مقاله انگلیسی: | برای دانلود رایگان مقاله انگلیسی با فرمت pdf اینجا کلیک نمائید |
| سال انتشار | 2000 |
| تعداد صفحات مقاله انگلیسی | 5 صفحه |
| تعداد صفحات ترجمه مقاله | 8 صفحه |
| مجله | – |
| دانشگاه | گروه بیولوژی، دانشگاه ایالتی پنسیلوانیا |
| کلمات کلیدی | – |
| نشریه | NCBI |
فهرست مطالب:
چکیده
مقدمه
رشد و نمو تار کشنده
تعیین سرنوشت سلول
شروع راه اندازی تار کشنده
رشد رأسی
ریشه مو و جذب املاح
جذب فسفر
جذب نیتروژن
پیش بینی برای اینده
بخشی از ترجمه:
مقدمه
الگوی مجرایی شکل رشد تار کشنده برای نقش ان در نگهداری ریشه و افزایش سطح قابل بهره برداری از خاک برای گیاهان ضروریست.شکل تار کشنده از سلول های اپیدرمی ریشه نشآت میگیرد.رشد ان در ۴ فاز رخ میدهد:تعیین سرنوشت سلول, راه اندازی, تیپ رشد پسین و بلوغ.بخاطر تفاوت این مرحله از رشد و نمو از تار کشنده بعنوان مدل سیستمی برای شروع فهم موارد زیر در گباهان استفاده میشود:
۰سرنوشت سلول را مشخص میکند(تعیین اینکه یک سلول تار کشنده باشد یا نه)
۰اطلاعات وابسطه به موقعیت را کد می کند(تار کشنده از کدام بخش سلول نشآت میگیرد)
.منطقه رشد(چگونه تشکیلات سلولی شکل مویی رشد را سازماندهی میکند)
بیشترین نقش تار کشنده در جایگاه جذب املاح است,مطالعه اساس ملکولی فعالیت جایگاه نقل وانتقال املاح را در ریشه معین میکند.در نقطه ی ویژه القای دانسته های ما در شکل و عملکرد تار کشنده باقی میماند و داوطلب های ملکولی برای تنظیم همه ی مراحل تکامل تار کشنده باقی می ماند و داوطلب های ملکولی برای تنظیم همه ی مراحل رشد و نمو تار کشنده شروع به پدیدار شدن میکند بعلاوه نقش تار کشنده در نقل ئ انتقال املاح شناخته میشود.ما در زمینه ی سازش و انطباق تار کشنده برای بهره برداری از خاک ساختار جامع ملکولی از رشد و نمو تار کشنده در نقل و انتقال را میبینیم.
بخشی از مقاله انگلیسی:
The tube-like growth pattern of root hairs is essential to theirfunction in root anchorage and for increasing the area ofsoil exploitable by the plant1. Root hairs form from rootepidermal cells. Their development occurs in four phases: cell fatespecification, initiation, subsequent tip growth and maturation(Fig. 1). Because of these distinct stages of development, roothairs have been used as a model system to begin to understandhow plants:• Specify cell fate (whether a cell is destined to make a root hairor not).• Encode positional information (where on a cell the root hairwill form).• Localize growth (how the cellular machinery is organized tomake hair-like growth).The root hairs’ role as major nutrient-uptake sites has also madethem an obvious site to study the molecular basis of nutrient transportactivities in the root. We stand at a particularly exciting pointin our understanding of root hair form and function. Molecularcandidates for regulators of all stages of root hair development arebeginning to emerge. In addition, defined root hair nutrient transportactivities have begun to be identified. We are seeing the beginningsof a comprehensive molecular characterization of the developmentaland transport activities that underlie the adaptations ofthe root hair for exploitation of the soil. Root hair developmentCell fate specificationAlthough it has been known for decades that only some root epidermalcells are destined to develop hairs (trichoblasts)2, the pastfew years have seen an explosion of information about how thisoccurs. The decision to become a trichoblast or not happens earlyin development. From the time of their formation in the meristematiczone, trichoblasts can be distinguished from atrichoblastsby differences in their cytoplasmic structure (e.g. reduced vacuolation)3. Two basic schemes describe root-hair-fate specification(Fig. 1). In plants, such as Phleum and Hydrocharis, trichoblastsform from an asymmetrical division of a protodermal cell. A secondtheme of development is seen in Arabidopsis. In this plant,trichoblasts form from epidermal cells overlying the junction oftwo cortical cells. This patterning leads to files of trichoblastsinterspersed with files of atrichoblasts4 (Fig. 1), and suggestsintricate cell-to-cell communication soon after formation in themeristem. The cortical cells might relay positional information to theoverlying epidermal cells to lay down these precise patterns of cellfate. Recent evidence suggests genes, such as TRANSPARENTTESTA GLABRA (TTG) and GLABRA2 (GL2), are also involved in fate specification in the shoot epidermis, and are negative transcriptionalregulators of root hair formation5–7. Conversely themyb-like transcription factor encoded by the CAPRICE gene isthought to be a negative regulator of non-hair fate8.Mutants that suppress root hair formation, or those that lead tothe production of ectopic root hairs, also indicate possible hormone(ethylene and auxin)-related mechanisms of cell fate specification.For example, in the ctr-1 mutant of Arabidopsis, all rootepidermal cells produce root hairs. CTR-1 encodes a protein kinaseof the Raf super-family that is involved in ethylene signal transduction9.Similarly, activators and inhibitors of ethylene synthesisalter trichoblast formation10, and the rhd6 root hair developmentalmutant, which fails to initiate root hairs correctly, can be rescuedby auxin or ethylene, and phenocopied by ethylene synthesisinhibitors11. Exactly how these hormones act is not known. It islikely that hormones act either independently or later than TTGand GL2 (Ref. 12), perhaps fixing the cell fate once it is specified.Recent work also suggests that trichoblasts and atrichoblastsmight have differential hormone sensitivities13. We anticipate thatthe identification of signaling elements, such as the CTR-1 kinase,coupled to the continuing characterization of the remarkablearray of root-hair-development mutants, identified by the effortsof many research groups, is just the beginning of the processof defining a molecular regulatory pathway for trichoblast fatespecification and root hair formation.Root hair initiationIn the trichoblast, the first morphological indications of root hairformation become evident when the cell begins to form a highlylocalized expansion from one side to form a bulge in the cell wall(Fig. 1). This is the process of root hair initiation. The site on thelateral wall of the trichoblast is precisely regulated. In Arabidopsis,for example, root hairs always form at the end of the cell nearestthe root apex14. This site can be shifted by ethylene or auxin treatment11,suggesting again that these hormones are critical regulatorsof root hair formation. The ability to shift the initiation sitealso implies that it is continuously and actively specified beforeroot hair emergence rather than being the result of a marker laiddown at the beginning of trichoblast development.
| عنوان فارسی مقاله: | بررسی عملکرد تار کشنده در گیاهان : تکامل تار کشنده و جذب املاح |
| عنوان انگلیسی مقاله: | Through form to function: root hair development and nutrient uptake |
