Home Archive for 2月 2025

Torno brevemente sul grande Platano padovano protagonista di alcuni miei post dei giorni scorsi.

Il Platano, già vittima di una drastica capitozzatura, è ora inserito in un programma pluriennale di ricostruzione che prevede il ricorso a successive, ragionate potature.

La scalarità del recupero intrapreso permette sia di contenere l'asportazione di massa fotosintetizzante entro i limiti di resilienza energetica dell'albero, che di evitare disordini ormonali che potrebbero favorire l'emissione di nuova e disorganizzata vegetazione avventizia. Seguendo questa articolazione temporale diviene inoltre possibile osservare criticamente la "risposta" del Platano ad ogni attività (emissione di nuova vegetazione, metamorfismo e mortalità fisiologica), adeguando quantitativamente e qualitativamente la potatura successiva tanto agli obiettivi finali del recupero stesso che alle esigenze contingenti del Platano.

Il tutto - come di prassi - in accordo con un programma diagnostico (analisi della stabilità) in grado di fornire anche indicazioni sulle caratteristiche meccaniche dell'albero.

Nelle foto viene presentato il "percorso" dell'albero da quando è nelle nostre mani (in effetti era già stato oggetto di una prima potatura post-capitozzo da parte di altri arboricoltori), attraverso i "prima" e "dopo" delle due potature fino ad oggi eseguite (2022 e 2025).

Si osservi in particolare la progressiva gerarchizzazione della massa rameale con passaggio dei tronchi reiterati traumatici ad una condizione di epitonia.

Presumibilmente saranno necessari altri due interventi prima che il Platano sia riconsegnato ad una condizione di pseudo-naturalità. Perché, non dobbiamo mai dimenticarlo, per quanto ci si adoperi, la capitozzatura...non si scorda mai!

Non ci vuole fretta, con gli alberi.

Servono conoscenza passione e rispetto; servono arboricoltori professionisti.

Con gli alberi di si collabora, non si combatte.🌿

#facciamoilmestierepiùbellodelmondo 💚

#proudtobeanarborist 💚

#dignityfortrees 💚 顯示較少

— 和 Luca De Marchi 及

其他 4 人

資料來源:

Giovanni Morelli

High-quality evergreen azalea genome reveals tandem duplication-facilitated low-altitude adaptability and floral scent evolution

Characteristics of Rhododendron ovatum and its genome assembly. (a) Low-altitude and evergreen characteristics of R. ovatum. The genus Rhododendron contains five main subgenera, of which two subgenera (Rhododendron and Hymenanthes) commonly called ‘rhododendron’ are mainly distributed in alpine and subalpine zone, and the other three (Azaleastrum, Tsutsusi, and Pentanthera) commonly called ‘azalea’ are distributed in mountain and hill zone. The subgenera of Rhododendron, Hymenanthes, and Azaleastrum are mostly evergreens, while Tsutsusi are mainly semi-evergreens and Pentanthera are deciduous. Genome sequences of R. delavayi and R. williamsianum in subgenus Hymenanthes, and R. simsii in subgenus Tsutsusi were previously reported (Soza et al., 2019; Yang et al., 2020; Zhang et al., 2017a). (b) Overview of the R. ovatum genome assembly. (i) The 13 pseudochromosomes, (ii) gene density, (iii) transposon elements, (iv) tandem repeats, and (v) collinear blocks of the R. ovatum genome.

Phylogenetic relationship and comparative genomics analyses. (a) Phylogenetic tree based on single-copy genes from 8 plant species in the Ericales, and tomato (S. lycopers) was used as the outgroup. The numbers in purple beside each node shows the estimated divergent time of each node (myr), and those in brackets are 95% confidence intervals for the time of divergence between different clades. The pie diagram on each branch of the tree represents the proportion of orthogroups undergoing gain (orange) or loss (blue) events, and the numbers beside the pie diagram denote the total number of expansion and contraction orthogroups. The numbers under each branch indicate evolutionary distance that represent genetic variance. (b) Gene expansions in R. ovatum compared to R. delavayi and R. williamsianum. Left panel shows enriched GO terms of expansive genes related to stress responses. Bottom and up panels show the names and gene numbers of the expansive gene families involved in the GO terms. The dots indicate corresponding relations between GO terms and gene families. The full names of gene families are listed in Data S3. (c) The phylogenetic tree of NAC genes from R. ovatum and representative plants showing the extremely expanded clade of ANAC001 in R. ovatum. Branches are colour-coded according to species. Asterisks (*) indicate the genes that have undergone positive selection (Ka/Ks > 1). Right penal shows dense tandem arrays of ANAC001 members that are distributed on chromosomes 7 and 12 of R. ovatum. (d) Co-expression network analysis based on a highly expressed NAC gene member (Ro_40853). Orange circles represent transcription factors and blue circles represent structural proteins.

資料來源:

https://onlinelibrary.wiley.com/doi/10.1111/pbi.13680

Whole genome duplications in plants: an overview from Arabidopsis

Fig. 1.

Chromosome status in the genus Arabidopsis after polyploidization events. A. arenosa and A. thaliana persist as both diploid and autotetraploid. Allopolyploid A. suecica is formed by a single hybridization event between A. thaliana and A. arenosa. Mechanisms leading to autotetraploids and allotetraploids are indicated. Other non-shown genus members also suffer polyploidization. Thus, A. lyrata autotetraploid are also frequent and A. kamchatica is originated from multiple allopolyploidization events between A. halleri and A. lyrata. Figure shows also status of endoreplicated tissues obtained by development-associated endocycles. Endoreplication not only occurs during the development of A. thaliana, but also in A. suecica and A. arenosa.

Fig. 2.

Morphological features associated with autoploidy in Arabidopsis. (A) Characteristic trichome morphology visualized by microscopy from diploid and tetraploid leaf (28-d-old rosette leaf #3–4). Note five-branched trichome from autotetraploid Arabidopsis (Col-0). (B) Scanning micrography of petal cells from diploid and tetraploid flowers. Note that in all cases, cells of tetraploid flowers are larger than the diploid. (C) Seeds of diploid and tetraploid Col-0 plants. (D) Stomatal cells visualized by light microscopy from diploid and tetraploid leaf (28-d-old rosette leaf #3–4).

Abstract

Polyploidy is a common event in plants that involves the acquisition of more than two complete sets of chromosomes. Allopolyploidy originates from interspecies hybrids while autopolyploidy originates from intraspecies whole genome duplication (WGD) events. In spite of inconveniences derived from chromosomic rearrangement during polyploidization, natural plant polyploids species often exhibit improved growth vigour and adaptation to adverse environments, conferring evolutionary advantages. These advantages have also been incorporated into crop breeding programmes. Many tetraploid crops show increased stress tolerance, although the molecular mechanisms underlying these different adaptation abilities are poorly known. Understanding the physiological, cellular, and molecular mechanisms coupled to WGD, in both allo- and autopolyploidy, is a major challenge. Over the last few years, several studies, many of them in Arabidopsis, are shedding light on the basis of genetic, genomic, and epigenomic changes linked to WGD. In this review we summarize and discuss the latest advances made in Arabidopsis polyploidy, but also in other agronomic plant species.

資料來源:

https://photos.google.com/album/AF1QipMndldtPARuOYSSfRHHZCJadNHCCU0QR_WuactG

解碼牛樟基因體闡明被子植物的演化

Stout camphor tree genome fills gaps in understanding of flowering plant genome evolution

a, Schematic representation of the intragenomic relationship among the 637 synteny blocks in the SCT genome. Synteny blocks (denoted by peach blocks) were assigned unambiguously into five linkage clusters representing ancient karyotypes and are colour coded. Purple blocks denote the synteny block assigned in the first linkage group (see also Supplementary Fig. 13). b, Schematic representation of the first linkage group within the SCT genome and their corresponding relationship in A. trichopoda.

a, Number of heterozygous biallelic SNPs per 100-kb non-overlapping windows is plotted along the largest 12 scaffolds. Indels were excluded. b, The history of effective population size was inferred using the PSMC method. One hundred bootstraps were performed and the margins are shown in light red. c, For every non-overlapping 100-kb window, the distribution is shown from top to bottom: gene density (percentage of nucleotides with predicted model), transcriptome (percentage of nucleotides with evidence of transcriptome mapping) and three different classes of repetitive sequences (percentage of nucleotides with transposable element annotation). The red T letter denotes the presence of a telomeric repeat cluster at the scaffold end. LINE, long interspersed nuclear element.

樟樹和牛樟染色體都是 n=12，但牛樟分子證據有發生全基因體複製(Whole genome duplication)，是基因倍體化沒有染色體數量倍增與增加，而是染色體變大不是整倍的，是每條染色體基因量有變多，和一般樟樹比對基因，牛樟有些基因份數是1到4倍。如果生長不好，很多基因是不表現的，看起來會像樟樹。

如果沒有朋友分享，我一直會認為是多倍体表現，是一篇值得珍藏文章。自然太多有趣的事還等著我們去發掘.............

資料來源:

https://ws.tfri.gov.tw/001/Upload/OldFile/files/%E5%B0%88%E8%A8%8A_153-1-2.pdf

https://www.nature.com/articles/s41477-018-0337-0

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Torno brevemente sul grande Platano padovano protagonista di alcuni miei post dei giorni scorsi.

Deletion and tandem duplications of biosynthetic genes drive the diversity of triterpenoids in Aralia elata

High-quality evergreen azalea genome reveals tandem duplication-facilitated low-altitude adaptability and floral scent evolution

Whole genome duplications in plants: an overview from Arabidopsis

解碼牛樟基因體闡明被子植物的演化 Stout camphor tree genome fills gaps in understanding of flowering plant genome evolution

Stout camphor tree genome fills gaps in understanding of flowering plant genome evolution