Leaf senescence in rice due to magnesium deficiency mediated defect in transpiration rate before sugar accumulation and chlorosis

Natsuko I. Kobayashi, Takayuki Saito, Naoko Iwata, Yoshimi Ohmae, Ren Iwata, Keitaro Tanoi, Tomoko M. Nakanishi

    Research output: Contribution to journalArticle

    38 Citations (Scopus)

    Abstract

    Magnesium (Mg) is an essential macronutrient supporting various functions, including photosynthesis. However, the specific physiological responses to Mg deficiency remain elusive. In this study, 2-week-old rice seedlings (Oryza sativa. cv. Nipponbare) with three expanded leaves (L2-L4) were transferred to Mg-free nutrient solution for 8days. In the absence of Mg, on day 8, L5 and L6 were completely developed, while L7 just emerged. We also studied several mineral deficiencies to identify specific responses to Mg deficiency. Each leaf was analyzed in terms of chlorophyll, starch, anthocyanin and carbohydrate metabolites, and only absence of Mg was found to cause irreversible senescence of L5. Resupply of Mg at various time points confirmed that the borderline of L5 death was between days 6 and 7 of Mg deficiency treatment. Decrease in chlorophyll concentration and starch accumulation occurred simultaneously in L5 and L6 blades on day 8. However, nutrient transport drastically decreased in L5 as early as day 6. These data suggest that the predominant response to Mg deficiency is a defect in transpiration flow. Furthermore, changes in myo-inositol and citrate concentrations were detected only in L5 when transpiration decreased, suggesting that they may constitute new biological markers of Mg deficiency.

    Original languageEnglish
    Pages (from-to)490-501
    Number of pages12
    JournalPhysiologia Plantarum
    Volume148
    Issue number4
    DOIs
    Publication statusPublished - 2013 Aug 1

    ASJC Scopus subject areas

    • Physiology
    • Genetics
    • Plant Science
    • Cell Biology

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