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Creators/Authors contains: "Long, Randall W."

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  1. ; ; ; ( , Tree Physiology)
    Abstract

    An on-going question in plant hydraulic research is whether there is intra-specific variability and/or plasticity in xylem traits. Plasticity could be important in taxa that colonize diverse habitats. We used Tamarix, a non-native woody plant, to investigate population differences in hydraulic conductivity (Ks), vulnerability-to-embolism curves and vessel anatomy. We also conducted a season-long drought experiment to determine water potentials associated with crown dieback of field-grown plants. We measured vessel length and diameter, and compared visual (micro-computed tomography; microCT) and hydraulic methods to quantify percentage loss in hydraulic conductivity (PLC). Among plants grown in a common environment, we did not find differences in our measured traits between two populations of Tamarix that differ in salinity at their source habitats. This taxon is relatively vulnerable to embolism. Within samples, large diameter vessels displayed increased vulnerability to embolism. We found that the microCT method overestimated theoretical conductivity and underestimated PLC compared with the hydraulic method. We found agreement for water potentials leading to crown dieback and results from the hydraulic method. Saplings, grown under common conditions in the present study, did not differ in their xylem traits, but prior research has found difference among source-site grown adults. This suggests that plasticity may be key in the success of Tamarix occurring across a range of habits in the arid southwest USA.

     
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  2. ; ; ; ; ( , Environmental Science & Technology)
    Full Text Available 
  3. ; ( , New Phytologist)

    This article is a Commentary onZhouet al. (2021),229: 1481–1491.

     
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  4. ; ; ; ; ; ( , Functional Ecology)
    Abstract

    Non‐structural carbohydrate (NSC) storage may be under strong selection in woody plant species that occur across broad environmental gradients. We therefore investigated carbon (C) allocation strategies in a widespread non‐native woody plant,Tamarix. We predicted that genotypes with exposure to episodic freeze events would show elevated NSC concentrations compared to warm‐adapted genotypes with the trade‐off of reduced growth and reproduction relative to warm‐adapted populations.

    We established an experimental common garden using genotypes ofTamarix, sourced across a strong thermal gradient within the introduced range. We measured seasonal NSC storage in coarse roots and stems, above‐ground growth and flower production.

    Autumn NSC concentrations were 50% higher in genotypes from sites with episodic spring freeze events compared to genotypes from warmer sites. These cold‐adapted genotypes also had a 2.3‐fold higher starch to soluble sugar ratio than warm‐adapted genotypes. Across all genotypes and seasons, NSC storage was inversely correlated with growth and reproduction.

    Results suggest thatTamarixfrom colder locations cope with freeze events by maintaining large storage pools to support tissue regrowth, but with the trade‐off of overall reduced growth and reproduction. Our results are consistent with rapid selection in C allocation strategies in response to climate in introduced woody species.

    A freePlain Language Summarycan be found within the Supporting Information of this article.

     
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