Root vascular bundle arrangements among cotton strains and cultivars

• Published in: Environmental and experimental botany 1985-01, Vol.25 (1), p.23-30
• Main Authors: McMichael, B.L., Burke, J.J., Berlin, J.D., Hatfield, J.L., Quisenberry, J.E.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; comparisons of strain T25 and strain T169; cotton; Economic plant physiology; Fundamental and applied biological sciences. Psychology; plant anatomy; Plant physiology and development; roots; vascular bundles; Water and solutes. Absorption, translocation and permeability; Water relations, transpiration, stomata
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/0098-8472(85)90045-0

Vascular bundle arrangements of young primary roots of exotic cotton ( Gossypium hirsutum L.) strains T25 and T169, and commercial cultivars ‘Acala SJ5’, ‘Coker 5110’, ‘Deltapine 16’, ‘Paymaster 266’, ‘Stoneville 213’ and ‘Tamcot 788’ were studied to determine if differences occurred in internal root anatomy. Seeds of each strain or cultivar were germinated and seedlings were grown in 17.4-cm long × 16.4-cm wide polyethylene growth pouches in a constant temperature (30°C) incubator without light. Hoagland's nutrient solution was added to each pouch prior to ‘planting’, and the seed were kept moist by a paper insert within the pouch. When the roots were 7 days old, samples of primary or ‘tap’ roots (5 cm from apex) were collected and examined with a light microscope. Measurements of primary root length, lateral root length, and total lateral root numbers were made daily on the T25 and T169 plants for a 7-day period. The vascular ‘bundle’ arrangement in all the commercial entries and in the T169 strain were tetrarch (four distinct bundles), while the vascular bundle arrangement of strain T25 was pentarch (five distinct bundles). A stereological analysis of the root vascular systems showed that the total cross-sectional vessel area per root was 45% greater in T25 than in T169. These differences were primarily because of an increased number of vessel elements as a result of an additional vascular bundle. There was an increase in lateral root development (increased number and length) in T25. The increased number of vessel elements in T25 suggested a decrease in root axial resistance to water flow. The internal root anatomy of T25 may be associated with characteristics of drought tolerant cotton and further research will begin to quantify these relationships.