Effects of light quantity on above-ground biomass investment patterns in the vine Lonicera periclymenum and the shrub Lonicera xylosteum
During, H. J.; Kwant, R. A.; Werger, M. J. A.
Architectural differences between plants should at least partly result from differences in biomass investment patterns. We studied this for two closely related species of Lonicera, a vine and a shrub, in full daylight and in moderate shade. We hypothesized that investment in stems would be more plastic in the vine L. periclymenum than in the shrub L. xylosteum in response to shade. Lonicera xylosteum attained a higher biomass than L. pericylmenum. By adjusting the SLA (ratio leaf area/leaf weight) of the leaves both species were able to reach nearly the same biomass in shade as in full daylight. Flowering occurred only in L. periclymenum; in the shade, fewer plants produced inflorescences. The plants of L. periclymenum produced significantly less, but longer branches in shade than in full daylight. This response is presumed to be the result of a direct influence of light quantity on branch recruitment from buds. It is considered advantageous for a climbing species in the vertically heterogeneous light climate that such plants experience in the field.