AOBPreview originally published online on January 5, 2004
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Annals of Botany 93: 211-220, 2004
© 2004 Annals of Botany Company
Characterization of a Lignified Secondary Phloem Fibre-deficient Mutant of Jute (Corchorus capsularis)
1 Plant Physiology Section, Central Research Institute for Jute and Allied Fibres (CRIJAF), Indian Council of Agricultural Research, Barrackpore, Kolkata 700 120, India
* For correspondence. E-mail palitpratip{at}yahoo.co.in
Received: 23 June 2003; ; Returned for revision: 22 September 2003; Accepted: 27 October 2003 Published electronically: 5 January 2004
• Background and Aims High lignin content of lignocellulose jute fibre does not favour its utilization in making finer fabrics and other value-added products. To aid the development of low-lignin jute fibre, this study aimed to identify a phloem fibre mutant with reduced lignin.
• Methods An x-ray-induced mutant line (CMU) of jute (Corchorus capsularis) was morphologically evaluated and the accession (CMU 013) with the most undulated phenotype was compared with its normal parent (JRC 212) for its growth, secondary fibre development and lignification of the fibre cell wall.
• Key Results The normal and mutant plants showed similar leaf photosynthetic rates. The mutant grew more slowly, had shorter internodes and yielded much less fibre after retting. The fibre of the mutant contained 50 % less lignin but comparatively more cellulose than that of the normal type. Differentiation of primary and secondary vascular tissues throughout the CMU 013 stem was regular but it did not have secondary phloem fibre bundles as in JRC 212. Instead, a few thin-walled, less lignified fibre cells formed uni- or biseriate radial rows within the phloem wedges of the middle stem. The lower and earliest developed part of the mutant stem had no lignified fibre cells. This developmental deficiency in lignification of fibre cells was correlated to a similar deficiency in phenylalanine ammonia lyase activity, but not peroxidase activity, in the bark tissue along the stem axis. In spite of severe reduction in lignin synthesis in the phloem cells this mutant functioned normally and bred true.
• Conclusions In view of the observations made, the mutant is designated as deficient lignified phloem fibre (dlpf). This mutant may be utilized to engineer low-lignin jute fibre strains and may also serve as a model to study the positional information that coordinates secondary wall thickening of fibre cells.
Key words: Jute, Corchorus capsularis, vascular development, mutant, secondary phloem fibre, lignin.