Morphological and physiological differences among cultivation lines of Undaria pinnatifida in a common garden experiment using a tank culture system

Sexual Difference in the Optimum Environmental Conditions for Growth and Maturation of the Brown Alga Undaria pinnatifida in the Gametophyte Stage

“…Both studies indicated species distribution differences affected by optimal temperatures for growth and maturation during the gametophyte stage. In addition, several morphological and physiological ecotypes have been observed in the sporophyte stage of U. pinnatifida [28][29][30]. The present results revealed that this alga also shows not only sexual differences but also ecological differences in physiological characteristics at its gametophytic stage: the optimum temperature for maturation in KGS was higher than in IWT and TKS.…”

“…One individual mature sporophyte of Undaria pinnatifida was collected at each of three sites ( Figure 1 , in April, 2017. Blade sections (2 cm × 2 cm) were excised from sporophylls and zoospores were released into sterilized seawater [29,30]. Zoospores were used to inoculate a 9-cm dish containing 30 mL of PESI medium [42] at a concentration low enough to allow individuals to be distinguished clearly, and they were cultivated at 20 • C under white fluorescent light at an intensity of 50 µmol m −2 s −1 .…”

“…The distinguishing morphological features of KGS include a shorter total length and wider blade compared with IWT and TKS ( Figure 1). Although the morphological features of IWT and TKS were similar at the sporophyte stage when they were cultivated under the same environmental conditions [30], they showed physiological differences in photosynthesis activity, and carbon and nitrogen assimilation [28]. It is therefore assumed that KGS, IWT, and TKS have different genetic backgrounds, and the morphological differences between IWT and TKS are emphasized by environmental factors.…”

“…Including different regional lines of U. pinnatifida allows exclusion of the effects of non-sexual genetic diversity on the optimum growth conditions. The lines we have used here are classified into two groups, which are known to show ecotypic differences at the sporophyte stage (photosynthetic rates and carbon and nitrogen assimilation [28]; nutrient-uptake kinetics [29]; and morphological characteristics [30]) but the gametophyte stage has not been examined previously.…”

Convergent evolution of niche structure in Northeast Pacific kelp forests

“…Close relatives may specialize in different positions along environmental gradients, leading to parallel adaptive radiation across subclades, possibly helping to maintain coexistence of species across broad geographic scales (Cavender‐Bares, Ackerly, et al, 2004; Cavender‐Bares, Kitajima, & Bazzaz, 2004; Cavender‐Bares et al, 2018; Losos, 2008; MacArthur, 1958). While many kelp species can alter their traits depending on habitat (reviewed by Koehl, Silk, Liang, & Mahadevan, 2008), genetic differentiation or speciation is likely to facilitate the evolution of more extreme trait differences than would be otherwise possible through plasticity (Augyte, Lewis, Lin, Neefus, & Yarish, 2018; Gerard, 1988; King, McKeown, Smale, & Moore, 2018; Sato et al., 2017). We further hypothesize that α niche traits may be more conserved than β niche traits across the kelps, leading to increased coexistence between distant relatives.…”