Involvement of the cotyledon in adventitious root initiation in Impatiens balsamina L. seedlings

• Published in: Annals of botany Vol. 58; no. 3; pp. 397 - 405
• Main Authors: Barker, W.G, Hussey, R.B, Horton, R.F
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01.09.1986; Academic Press Inc; Academic Press
• Subjects: Adventitious roots; balsam; Biological and medical sciences; collet; cotyledon; Cotyledons; Embryos; Fundamental and applied biological sciences. Psychology; General aspects; Hypocotyls; Impatiens balsamina; Petals; Plant physiology and development; Plant roots; Root primordia; root regeneration; seed germination; Seedlings; Seeds; Swelling; Vegetative apparatus, growth and morphogenesis. Senescence; Morphogenesis; Impatiens balsamina; Cotyledon; Root; Dicotyledones; Angiospermae; Balsaminaceae; Adventitious root; Spermatophyta
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/oxfordjournals.aob.a087218

Adventitious root primordia are found in the pre-hypocotyl tissue of developing seeds of Impatiens balsamina L. by the third week after petal drop, and are present in the mature seed. After germination, the adventitious roots emerge from a collet swelling on the hypocotyl of the young seedlings. Removal of the collet during the first five days results in the formation of another at the base of the remaining hypocotyl. Older seedlings respond to the excision of the collet by producing one or more roots near the cut end, unless the cut is made close to the cotyledon, when, even in nine-day seedlings, a reduced collet is formed associated with four or fewer roots. The influence of the cotyledon on collet/root regeneration diminishes in older seedlings and in these is manifested only in hypocotyl tissue adjacent to that organ.