Abstract

HAJIBOLAND, R  and  POSCHENRIEDER, C. Localization and compartmentation of Al in the leaves and roots of tea plants. Phyton (B. Aires) [online]. 2015, vol.84, n.1, pp.86-100. ISSN 1851-5657.

Under acid soil conditions, solubility of aluminum (Al) increases leading to toxicity for plants. Al accumulator species such as tea, however, accumulate high levels of Al in tissues without toxicity symptoms. In this work, Al localization and compartmentation were studied in tea [Camellia sinensis (L.) O. Kuntze] grown hydroponically at 0 or 100 µM Al for eight weeks. Plant dry matter production was significantly higher in the presence of Al and accumulated up to 1.21 and 6.18 mg Al/g DW in the leaves and roots, respectively. About 40-50% of Al was partitioned into cell wall (CW)-bound fraction without any difference among leaves of different age and roots. A significant increase of the soluble phenolics fraction by Al was observed in both leaves and roots. Conventional and confocal laser scanning microscopy images of morin-stained roots indicated a high fluorescence signal in the caps and adjacent mersitematic cells. Towards basal parts, however, Al tended to accumulate mainly in the root hairs, rhizodermal and endodermal cell layers and slightly in the cortex while it was clearly excluded from the central cylinder. A high Al-morin signal was detected from the CW compared with other parts of the cells. Relatively high green fluorescence signal was emitted from the epidermal cell layer, trichomes, vascular bundle region and stomatal cells of particularly young leaves. Our study provides evidences for involvement of both avoidance and tolerance mechanisms for Al in tea plants.

Keywords : Aluminum; Morin; Fluorescence; Tea; Confocal laser scanning microscopy (CSLM).

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