Preliminary Studies on Pithiness of Sugarcane

Abstract

The normal cane stalk has a structure similar to other monocotyledons. The rind is the hard outer layer, consisting of an outer epidermal Inyer and inner cortical Inyer made up of thick sclerenchymatous cells. The pith portion refers to the portion enclosed by the rind. The size of the pith cell increases towards the centre. The fibro-vascular bundles are embedded in the pith. They are more numerous near the rind than in the centre of the coro. The pith cells are responsible for normal chemical reactions of Sugarcane plant, and for storage and utilization of sugar. All sugars stored in the stem are in solution in these cells. Under normal conditions, the interior of the stalk is solid except for a very small cavity (1). But under certain conditions, which are adverse to normal cane growth, these cells become dead, and this condition is usually referred to as pith. Thus pith has lost its original meaning, and when associated with sugarcane, "Pith denotes the chalky white tissue consisting of dead parenchymatous cells with a few fibro-vascular strands" (8). Since the formation of pith, means the death of the parenchymatous cells, responsible for storage and ntilization of sugars, the pith formation is an undesirable character and this leads to the loss of cane and sugar storing tissues. (1, 5, 12). Normally, the stalk of the inflorescence is pithy and this pithiness extends into a greater part of the stalk (1). Arrowed canas are found to be more pithy than unarrowed canes (7). The influence of adverse growing conditions, especially limiting water supply and soil types have also been reported (9). Frequency of irrigations seems to reduce pith formation (12). Increasing the number of irrigations and changing the planting time from February to April decreased the pithiness (Verma loccit).