Cultivar and Environmental Effects on Freezing Tolerance of Narrow-Leaf Plantain
- R. Howard Skinner *
Improved cultivars of narrow leaf plantain (Plantago lanceolata L.) have received increasing attention as possible pasture species for the northeastern USA because of their productivity during drought and high nutritive value. However, the cultivars currently available do not have sufficient freezing tolerance to survive northeastern U.S. winters. This experiment examined the relationship between shoot growth rate and root:shoot partitioning during cold-hardening and the freezing tolerance of ‘Lancelot’ and ‘Tonic’ plantain compared with ‘PG700’, an experimental line collected from the eastern USA. I hypothesized that PG700 would exhibit reduced shoot structural growth and increased carbohydrate storage in roots during cold-hardening, resulting in increased freezing tolerance and survival. In growth chamber experiments, seedlings were cold hardened for 21 d and then frozen at −12°C for 3 h. Survival was evaluated after a 21-d recovery period. The experiment was conducted twice. Survival was greatest for PG700 (58%), followed by Lancelot (33%) and Tonic (18%) (P < 0.01). When combined across cultivars, survival was 59% in Trial 1 compared with 11% in Trial 2 (P < 0.01). None of the measured parameters including overall root and shoot growth or relative partitioning between roots and shoots were related to cultivar differences in freezing tolerance. Reduced survival in Trial 2 was accompanied by high nitrogen uptake and vigorous shoot relative to root growth during the cold-hardening period. Thus, reduced shoot growth was accompanied by increased freezing tolerance when differences in survival were induced by environmental effects but was not related to genetic differences in survival.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2005.