Localization of Casparian Bands and Crystal Cells in Relation to Aluminum Distribution in the Primary Root of Eddo under Aluminum Treatment

Abstract

The primary roots of eddo (Colocasia esculenta (L.) Schott var. antiquorum Hubbard & Rehde) were treated with aluminum, and the localization of Casparian bands and crystal cells in relation to aluminum was investigated. The calcium oxalate crystal idioblasts (crystal cells) were localized at the peripheral parts of cortex between about 0.5 mm and 6 mm from the tip of primary roots. The crystal cells were arranged in tubular form, which is referred to as ‘tubular arrangement of crystal cells’. The Casparian band was apparently detected in the endodermis at 3 mm from the root tip of primary roots treated with aluminum, under a fluoresence microscope with berberin hemi-sulfate. Aluminum was significantly stained with eriochrome cyanine in the root apical region of eddo after aluminum treatment. Not only in the periphery part of stele, but also the external part of the tubular arrangement of crystal cells was significantly stained. In addition, marked accumulation of aluminum stained with lumogallion was observed inside the crystal cells by z-staking observation with a confocal laser scanning microscope. The results suggested that Casparian bands in endodermis and the tubular arrangement of crystal cells obstructed the influx of aluminum into the inside of stele.

Keywords

• Aluminum
• Calcium oxalate crystal
• Casparian band
• Colocasia esculenta
• Eddo
• Oxalate
• Taro