Changes in Molecular Weight of Cellulose in the Pea Epicotyl during Growth 1

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A procedure is described for preparing cellulose nitrate from pea tissues (Pisum sativum L. var. Alaska) in quantitative yield, undegraded and uncontaminated by other polysaccharides. The average degree of polymerization of this product, estimated from viscosity measurements, increased during cell growth and development from a value of about 5000 glucose units in the apical meristem (plumule plus hook) to values near 8000 in fully grown maturing tissues (>20 mm from apex). The cellulose content per cell also increased (approximately 10-fold) during growth in these tissues, as did particulate glucan synthetase activity (3-fold rise). Since the yield of soluble cellulase activity is known to decrease from high values in the meristem to barely detectable amounts in mature tissues, it is suggested that the relative levels and properties of these hydrolytic and synthetic enzyme activities control the amount and degree of polymerization of cellulose formed during cell expansion in the pea epicotyl.

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