Conservation Evaluation of the Prairie Lupine, Lupinus lepidus var. lepidus, in Canada

In Canada, Prairie Lupine, Lupinus lepidus var. lepidus, is restricted to southeastern Vancouver Island. Of the nine sites where it has been collected, five are extirpated and the status of two of the populations is uncertain. There are two extant populations; some of the other sites may contain the species in the seed bank. Some of the sites are protected to a certain extent from direct habitat destruction by their remote location, although introduced herbaceous species may pose a serious threat by preventing the establishment of the species at other sites. Fire suppression or the lack of other types of disturbance also likely plays a role in discouraging emergence of Lupinus lepidus.

IN VITRO CONSERVATION OF THE NORTHERN GENOME OF LUPINUS LEPIDUS

Lupinus lepidus is a dwarf perennial lupine native to British Columbia. It possesses high horticultural potential, but the only known population in British Columbia averages 70 plants and is under constant threat of destruction. Lupinus lepidus is variable from seed and very difficult to propagate from cuttings. To protect the northern genome of L. lepidus, and to help introduce this plant to the nursery trade, we have investigated the feasibility of micropropagation for expansion of the supply of plant material. A regeneration procedure has been developed that enables multiple L. lepidus plantlets to be obtained directly from cotyledon explants of 10-day-old seedlings. More than 40 microshoots per explant were induced from cotyledonary node explants after placing them on MS medium containing BAP at 1 mg·liter–1 and NAA at 0.05 mg·liter–1 for 3 weeks. The regenerated shoots grew vigorously on a hormone-free, half-strength MS medium and could be multiplied on the same medium every 2 weeks. This micropropagation cycle has been used continuously for 9 months. Alternatively, 15 to 20 plantlets can be forced to develop from the axillary buds on the stems of 5-month-old seedlings by withholding sucrose from half-strength MS medium. The induced plantlets could be further propagated on the same medium, but they displayed less vigor than those obtained from the cotyledonary node explants.