塩性条件下のトウモロコシおよびヒマワリにおける水とイオンの吸収と輸送 Absorption and Transport of Water and Ions in Corn and Sunflower Plants Grown Under Saline Conditions

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Abstract

物理的・生理的過程を通して根圏の塩類化に影響を及ぼす植物の水とイオンの輸送を解析するために,NFT水耕栽培システムを用いて,塩性条件下におけるトウモロコシとヒマワリの根による水とイオンの吸収,蒸散速度,リーフコンダクタンス,根の道管液のイオン濃度,植物体内のイオン含量を計測した。根の吸水速度は,ヒマワリよりトウモロコシにおいて小であり,これは塩ストレスに対する気孔閉鎖がトウモロコシにおいて発生したことに起因する。植物にとって必須元素であるNO<sub>3</sub><sup>-</sup>,PO<sub>4</sub><sup>3-</sup>,K<sup>+</sup>は,根の能動的および選択的吸収によって道管内に高濃度に集積した。植物の生育に必須でないNa<sup>+</sup>は,トウモロコシにおいてはその導管内と器官内に高い集積は見られず,トウモロコシによるNa<sup>+</sup>の吸収機能が低いことが分かった。一方,ヒマワリにおいては,水分吸収に伴なって,Na<sup>+</sup>に加えてMg<sup>2+</sup>,Ca<sup>2+</sup>,Cl<sup>-</sup>,SO<sub>4</sub><sup>2-</sup>の高い吸収・輸送機能が観察された。以上のように,植物の種間差による水とイオンの輸送機能の差異が認められた。乾燥・半乾燥地域の重要課題である塩類化農地の持続的かつ効果的な管理を行ううえでは,このような植物による輸送機能を考慮に入れることが必要と考える。

In order to analyze absorption and transport of water and ions in plants affecting the salinization in the root zone through physical and physiological processes, we measured water and ion uptake by roots, transpiration rate, leaf conductance, and ion concentrations in root xylem sap and other plant tissues of corn and sunflower grown under saline conditions using a nutrient film technique system. The rate of root water uptake was lower in corn than in sunflower, where the daytime stomatal closure in response to the excessive water stress induced by the saline solution was occurred in corn but not in sunflower. NO<sub>3</sub><sup>-</sup>, PO<sub>4</sub><sup>3-</sup> and K<sup>+</sup> were highly concentrated in the xylem sap as a result of the active and selective uptake of nutrients by roots of both corn and sunflower. Na<sup>+</sup>, which is not an essential element for plant growth, was not highly concentrated in the xylem sap or plant tissues of corn because corn exhibited a poor Na<sup>+</sup> absorption and transportation ability. On the other hand, sunflower had a greater ability to absorb water, Na<sup>+</sup>, Mg<sup>2+</sup>, Ca<sup>2+</sup>, Cl<sup>-</sup>, and SO<sub>4</sub><sup>2-</sup>, and to transport these ions from the roots to the shoot. These differences in absorption and transport of water and ions indicate that sunflower is more salt tolerant than corn. The effects of these absorption and transport characteristics on plant growth and soil salinity should be taken into account for sustainable and effective plant production in salinized crop fields.

Journal

  • Journal of Agricultural Meteorology

    Journal of Agricultural Meteorology 65(1), 19-26, 2009-03-10

    The Society of Agricultural Meteorology of Japan

References:  18

Codes

  • NII Article ID (NAID)
    10025613933
  • NII NACSIS-CAT ID (NCID)
    AN00200732
  • Text Lang
    ENG
  • Article Type
    ART
  • ISSN
    00218588
  • NDL Article ID
    10232788
  • NDL Call No.
    Z18-388
  • Data Source
    CJP  NDL  J-STAGE  JASI 
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