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- Huttunen, Piritta, et al.
(författare)
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Leaf trichome production and responses to defoliation and drought in Arabidopsis lyrata (Brassicaceae)
- 2010
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Ingår i: Annales Botanici Fennici. - Helsinki : Finnish Zoological and Botanical Publishing Board. - 0003-3847 .- 1797-2442. ; 47:3, s. 199-207
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Tidskriftsartikel (refereegranskat)abstract
- Leaf trichomes can protect plants against herbivory and drought, but can be costly to produce. Theory suggests that selection for reduced costs of resistance may result in the evolution of inducible defences. We quantified variation in tolerance to drought and defoliation, and tested the hypotheses that (a) tolerance is associated with cost, (b) leaf trichome production increases tolerance to drought, and (c) trichome production is increased in response to defoliation and drought stress in Arabidopsis lyrata (Brassicaceae). Eight maternal half-sib families were exposed to two watering regimes and four defoliation treatments in a factorial design. Tolerance to drought varied among families and was inversely related to leaf size, but was not related to trichome density. Family mean performance in the low-watering treatment tended to correlate negatively with that in the control treatment. Trichome production was not induced by defoliation or drought stress. The results suggest that there is genetic variation in tolerance to drought in the study population, that tolerance to drought is associated with a cost, and that trichome production does not increase tolerance to drought in A. lyrata.
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| 2. |
- Løe, Geir, 1973-
(författare)
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Ecology and Evolution of Resistance to Herbivory : Trichome Production in Arabidopsis lyrata
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, I examine variation in occurrence and performance of glabrous and trichome-producing plants of the perennial herb Arabidopsis lyrata. I combine field studies and genetic analysis to (1) examine the function of trichomes as a resistance character in natural populations, (2) compare the magnitude of population differentiation in trichome-production and at putatively neutral marker loci, (3) examine the molecular genetic basis of trichome-production, and (4) quantify the effects of herbivore removal on population growth and relative performance of glabrous and trichome-producing plants. In a survey of 30 populations of A. lyrata in Norway and Sweden, I documented spatiotemporal variation in damage from insect herbivores. With few exceptions, glabrous plants were more damaged by herbivorous insects than trichome-producing plants in polymorphic populations. Damage levels varied substantially among populations and among years. The intensity of herbivory quantified as mean leaf removal to glabrous plants was higher in polymorphic populations than in monomorphic glabrous populations. Within the Swedish range, populations were more strongly differentiated at the locus coding for glabrousness than at eight putatively neutral isozyme loci. This is consistent with the hypothesis that trichome production is subject to divergent selection. A study of the genetic basis of trichome production showed that glabrousness was associated with mutations in an orthologue to GLABROUS1, a regulatory gene known to cause glabrousness in A. thaliana. Comparative data indicate that the genetic basis of glabrousness varies among populations. Experimental removal of insect herbivores in a natural A. lyrata population increased population growth rate and the relative fitness of the glabrous morph. The results suggest that insect herbivory may influence both population dynamics and selection on trichome production in A. lyrata.
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