1. Root, stem and leaf traits are thought to be functionally coordinated to maximize the efficiency of acquiring and using limited resources. However, evidence is mixed for consistent whole-plant trait coordination among woody plants, and we lack a clear understanding of the adaptive value of root traits along soil resource gradients. If fine roots are the below-ground analogue to leaves, then low specific root length (SRL) and high tissue density should be common on infertile soil. Here, we test the prediction that root, stem and leaf traits and relative growth rate respond in unison with soil fertility gradients. 2. We measured fine root, stem and leaf traits and relative growth rate on individual seedlings of 66 tree species grown in controlled conditions. Our objectives were (i) to determine whether multiple root traits align with growth rate, leaf and stem traits and with each other and (ii) to quantify the relationships between community-weighted mean root traits and two strong soil fertility gradients that differed in spatial extent and community composition. 3. At the species level, fast growth rates were associated with low root and stem tissue density and high specific leaf area. SRL and root diameter were not clearly related to growth rate and loaded on a separate principal component from the plant economic spectrum. 4. At the community level, growth rate was positively related to soil fertility, and root tissue density (RTD) and branching were negatively related to soil fertility. SRL was negatively related and root diameter was positively related to soil fertility on the large-scale gradient that included ectomycorrhizal angiosperms. 5. Synthesis. Root, stem and leaf tissue traits of tree seedlings are coordinated and influence fitness along soil fertility gradients. RTD responds in unison with above-ground traits to soil fertility gradients; however, root traits are multidimensional because SRL is orthogonal to the plant economic spectrum. In contrast to leaves, trees are not constrained in the way they construct fine roots: plants can construct high or low SRL roots of any tissue density. High RTD is the most consistent belowground trait that reflects adaptation to infertile soil.Key-words: determinants of plant community diversity and structure, leaf economic spectrum, plant economic spectrum, root branching, root diameter, root economic spectrum, root tissue density, soil fertility, specific root length, wood economic spectrum P erez-Ramos et al. 2012;Reich 2014;de la Riva et al. 2016). Investment in cheap tissue promotes fast growth, but comes at the cost of a short life span, whereas investment in expensive tissue produces long-lived organs that have slower metabolic rates. The hypothesis that leaves, stems and roots are coordinated is intuitive from both evolutionary and biophysical perspectives: being fast at acquiring and processing resources is only advantageous when all organs are operating
Advances in the sequencing of DNA extracted from media such as soil and water offer huge opportunities for biodiversity monitoring and assessment, particularly where the collection or identification of whole organisms is impractical. However, there are myriad methods for the extraction, storage, amplification and sequencing of DNA from environmental samples. To help overcome potential biases that may impede the effective comparison of biodiversity data collected by different researchers, we propose a standardised set of procedures for use on different taxa and sample media, largely based on recent trends in their use. Our recommendations describe important steps for sample pre-processing and include the use of (a) Qiagen DNeasy PowerSoil ® and PowerMax ® kits for extraction of DNA from soil, sediment, faeces and leaf litter; (b) DNeasy PowerSoil ® for extraction of DNA from plant tissue; (c) DNeasy Blood and Tissue kits for extraction of DNA from animal tissue; (d) DNeasy Blood and Tissue kits for extraction of DNA from macroorganisms in water and ice; and (e) DNeasy PowerWater ® kits for extraction of DNA from microorganisms in water and ice. Based on key parameters, including the specificity and inclusivity of the primers for the target sequence, we recommend the use of the following primer pairs to amplify DNA for analysis by Illumina MiSeq DNA sequencing: (a) 515f and 806RB to target bacterial 16S rRNA genes (including regions V3 and V4); (b) #3 and #5RC to target eukaryote 18S rRNA genes (including regions V7 and V8); (c) #3 and #5RC are also recommended for the routine analysis of protist community DNA; (d) ITS6F and ITS7R to target the chromistan ITS1 internal transcribed spacer region; (e) S2F and S3R to target the ITS2 internal transcribed spacer in terrestrial plants; (f) fITS7 or gITS7, and ITS4 to target the fungal ITS2 region; (g) NS31 and AML2 to target glomeromycota 18S rRNA genes; and (h) mICOIintF and jgHCO2198 to target cytochrome c oxidase subunit I (COI) genes in animals. More research is currently required to confirm primers suitable for the selective amplification of DNA from specific vertebrate taxa such as fish. Combined, these recommendations represent a framework for efficient, comprehensive and robust DNA-based investigations of biodiversity, applicable to most taxa and ecosystems. The adoption of standardised protocols for biodiversity assessment and monitoring using DNA extracted from environmental samples will enable more informative comparisons among datasets, generating significant benefits for ecological science and biosecurity applications.
The Helichrysum-Anaphalis-Pseudognaphalium (HAP) clade is a major component of the tribe Gnaphalieae (Compositae) and includes the genera Helichrysum, Anaphalis, Achyrocline and Pseudognaphalium. Allopolyploid origins for at least two clades within the HAP clade have previously been suggested, one involving the genus Anaphalis and the MediterraneanAsian Helichrysum species, and a second one involving part of Pseudognaphalium. In the present paper, with the use of two nuclear ribosomal and two plastid DNA markers and an extensive sampling of the HAP clade, further evidence relevant to the origin, composition and closest relatives of these clades is provided, and additional cases of incongruence are discussed. The superposition of distribution areas on the phylogeny suggests that the HAP clade originated in the Cape region of southern Africa and subsequently dispersed to and diversified in the Afromontane regions of east southern Africa, mainly the Drakensberg, before spreading northward and giving rise to several lineages in afromontane and afroalpine areas of central tropical Africa and in Madagascar. Allopolyploidy may have preceded the dispersal and diversification of the HAP lineage out of Africa to the Mediterranean area, and to the Americas and Asia. Finally, discussion on the distribution of several morphological characters in the phylogeny and their taxonomic relevance is also provided, with views on the need for a new generic delimitation.
Phylogenetic analyses have suggested that the everlasting daisy tribe Gnaphalieae colonized the globe repeatedly and rapidly from southern Africa. However, both the circumscription of monophyletic groups of "out of Africa" Gnaphalieae genera and the identification of their sister groups in southern Africa has proved difficult. We have analysed sequences of nrDNA spacers (ITS, ETS), cpDNA (ndhF, trnL intron, trnL-trnF intergenic spacer, trnK intron), and low-copy nuclear markers to examine selected relationships within the crown radiation of the tribe. We focused on relationships among two putative clades suggested by previous studies and a representative sampling of genera endemic to Australasia. Incongruities between nrDNA and cpDNA trees are frequent and some involve robustly supported clades. However, trees generated for two lowcopy nuclear markers are largely congruent with each other but imply that allopolyploidy preceded the radiations of at least four separate extant lineages within the tribe, one largely or entirely restricted to Australasia, one almost global, and two still poorly sampled. Collectively, these four putative allopolyploid lineages may account for more than half of the described species diversity of the tribe.
The generic taxonomy of the Nothofagaceae is revised. We present a new phylogenetic analysis of morphological characters and map these characters onto a recently published phylogenetic tree obtained from DNA sequence data. Results of these and previous analyses strongly support the monophyly of four clades of Nothofagaceae that are currently treated as subgenera of Nothofagus. The four clades of Nothofagaceae are robust and well-supported, with deep stem divergences, have evolutionary equivalence with other genera of Fagales, and can be circumscribed with morphological characters. We argue that these morphological and molecular differences are sufficient for the four clades of Nothofagaceae to be recognised at the primary rank of genus, and that this classification will be more informative and efficient than the currently circumscribed Nothofagus with four subgenera. Nothofagus is recircumscribed to include five species from southern South America, Lophozonia and Trisyngyne are reinstated, and the new genus Fuscospora is described. Fuscospora and Lophozonia, with six and seven species respectively, occur in New Zealand, southern South America and Australia. Trisyngyne comprises 25 species from New Caledonia, Papua New Guinea and Indonesia. New combinations are provided where necessary in each of these genera.
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