Effects of salt Stress on Root Anatomy and Hydraulic Conductivity of Barley Cultivars

Document Type : Research Paper

Authors

1 Department of Agroecology, College of Agriculture and Natural Resources of Darab, Shiraz University, Shiraz, I. R. Iran

2 Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, I. R. Iran

Abstract

A hydroponic experiment was carried out to compare root anatomy and hydraulic conductivity of four barley cultivars including Valfajr, Karoon, Afzal and Zarjo under salt stress conditions. The results showed that under salt stress, the minimum diameter of vessels was observed in the peripheral metaxylem of seminal roots of Valfajr cultivar and in adventitious roots; Karoon with 19±3 µm had maximum diameter of vessels. In all barely cultivars, salt stress affected the diameter of central and peripheral metaxylem vessels more negatively in comparison to the number of the vessels. The mature xylem vessels of the seminal roots of the Valfajr and Zarjo cultivars had the most lignified cell walls. When the plants were exposed to salt stress, the casparian bands could be detected more in the seminal roots as U-shape and not in the adventitious roots. The lowest lignification thickness of cell wall (0.78 µm) was observed in the central metaxylem vessels of adventitious roots of Afzal cultivar under salt stress. Also, Afzal cultivar with highest surface area and lowest thickness of lignified cell walls, had the highest seminal root hydraulic conductivity (5.84×10-9 m s-1 MPa-1), whereas hydraulic conductivity was decreased to 3.21 and 3.17×10-9 m s-1 MPa-1 in Valfajr and Zarjo cultivars, respectively. Overall, Afzal and Karoon cultivars were found to perform better in water uptake at the early stages of growth due to less lignified cell walls of xylem in seminal and adventitious roots under salt stress conditions. Further research on hydraulic conductivity could be recommended.

Keywords

Main Subjects

Article Title [Persian]

تاثیر تنش شوری روی آناتومی و هدایت هیدرولیک ریشه ارقام جو

Authors [Persian]

  • احسان بیژن زاده 1
  • کبری مقصودی 2
1 دانشگاه شیراز
2 دانشگاه شیراز
Abstract [Persian]

آ‏ناتومی و هدایت هیدرولیک ریشه چهار رقم جو والفجر، کارون، افضل و زرجو در یک پژوهش هیدروپونیک در شرایط شوری مورد بررسی قرار گرفت. نتایج نشان داد در شرایط شوری، کمترین قطر آوند چوبی جانبی ریشه‌های بذری، در رقم والفجر مشاهده شد و در ریشه های نابجا، رقم کارون با 3±19 میکرو متر بیشترین قطر آوند چوبی جانبی را داشت. در همه ارقام جو، تأثیر منفی تنش شوری بر قطر آوند های چوبی مرکزی و جانبی بیش از تعداد آنها بود. دیواره سلولی آوندهای چوبی ریشه های بذری والفجر و زرجو بیشتر از سایر ارقام چوبی شده بودند. در شرایط تنش شوری، نوار کاسپاری به صورت یو شکل در ریشه های بذری بود که در ریشه های نابجا وجود نداشت. کمترین ضخامت لایه چوبی شده دیواره سلولی (78/0 میکرو متر) در آوند های چوبی مرکزی ریشه های نابجای رقم افضل در تنش شوری مشاهده گردید. همچنین رقم افضل با بیشترین سطح ریشه و کمترین ضخامت لایه چوبی شده دارای بیشترین هدایت هیدرولیک ریشه های بذری) 9-10×84/5 متر بر ثانیه بر مگا پاسکال) بود در حالیکه در والفجر و زرجو هدایت هیدرولیک به ترتیب به 9-10×21/3 و 9-10×17/3 متر بر ثانیه بر مگا پاسکال کاهش یافت. به طور کلی، جو افضل و کارون به دلیل ضخامت کمتر لایه چوبی در سلول های آوندی در ریشه بذری و نابجا و بدنبال آن هدایت هیدرولیک و نسبت ریشه به ساقه بیشتر، کارکرد بهتری در جذب آب در مراحل اولیه رشد داشتند. پژوهش های تکمیلی در این راستا قابل توصیه است.

Keywords [Persian]

  • آوند چوبی مرکزی
  • هدایت هیدرولیک
  • دیواره سلولی چوبی شده
  • ریشه های بذری

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