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Pak. J. Bot., 46(2): 477-482, 2014.

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ENVIRONMENTAL FACTORS AFFECT CALCIUM OXALATE CRYSTALS FORMATION IN TRADESCANTIA PALLIDA (COMMELINACEAE)

AISHA SALEEM KHAN^1* AND REHAN SIDDIQI²

Abstract: Tradescantia pallida has major types of calcium oxalate crystals i.e., raphide, prismatic, and druse that are widely  distributed within collenchmya, cortical and vascular parenchyma in the stem. However, mechanisms involved in crystal formation in response to stress conditions are not properly understood. In order to evaluate formation of these crystals in response to heavy metals i.e., mercury, sections of control (untreated) and mercury treated plants were prepared, stained with toluidine blue and photographed (infinity software). Mercuric chloride at high doses increased all types of crystals as compared with low doses; suggesting that mercury stress increases metabolic activities of Tradescantia that produce crystals may be, in order to defend themselves. So in T. pallida, crystal formation is influenced by mercury stress that increased raphide and prismatic crystals in the treated plants. However, biochemical aspects involved in oxalic acid formation and release of Ca by Hg need to be explored more.

¹Department of Biological Sciences, Forman Christian College, Lahore, Pakistan

²Department of Biological Sciences, Forman Christian College, Lahore, Pakistan.

^*Corresponding author e-mail: aishasaleemkhan@fccollege.edu.pk