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Question We analyse the contribution of plant-plant interactions, particularly the outcome of plant competition and plant facilitation, on vegetation dynamics as a result of extreme drought episodes. These events will likely become more frequent under climate change, can induce vegetation die-off and alter community dynamics. We study succession in a shrubland that tends to be replaced by juniper ( J uniperus phoenicea) woodland. Due to drought, shrubland die-off may result in competition release favouring J . phoenicea juveniles, and accelerating shrubland replacement. Alternatively, deleterious abiotic stress may increase after loss of vegetation cover protection. Location Mediterranean coastal shrublands, S outh S pain ( D onana N ational P ark). Methods Field estimates of plant growth, production of needle-like leaves, water-use efficiency ( WUE ; leaf [delta] super(13) C ) and N leaf content of J . phoenicea juveniles in relation to plant size, drought-induced damage, cover and habit characteristics of surrounding vegetation, and drought-induced defoliation of the surrounding vegetation. Results Juniperus phoenicea juveniles growing beneath a dense vegetation canopy, particularly trees and large shrubs, were less damaged during the extreme drought episode. Plant size correlated negatively with damage. Post-drought growth was higher in juveniles partially released from the vegetation canopy, supporting the existence of a balance between competition and facilitation. Cover of pines, large shrubs and spiny shrubs favoured growth of juveniles. Needle-like juvenile leaves were more abundant in plants covered by the surrounding vegetation or in moderately damaged plants, but less abundant in plants without damage. Higher leaf [delta] super(13) C values - indicating water stress - were measured in plants more damaged by drought and in those without canopy protection, or under vegetation strongly affected by drought. Leaf N content was lower in undamaged plants and individuals covered by surrounding vegetation. Conclusion We did not find evidence that gaps opened by drought promoted growth of the potential replacing J . phoenicea. Thus, drought-induced enhancement of successional replacement of shrublands with woodlands was not supported; instead, our findings foresee shrubland prevalence under future climate change conditions. Plant facilitation will play a relevant role in this process. Thus, we herein extend the relevance of plant-plant interactions to extreme drought episodes related to climate change, highlighting their role as drivers of community dynamics. The study illustrates the outcome of competence and facilitation to community dynamics under a climate change scenario where extreme climatic episodes are becoming more frequent. Empirical data from a Mediterranean shrubland subjected to successional replacement, shows that drought events disrupt this dynamics diminishing the facilitative effect of shrubland cover on the establishment of juveniles of the short tree Juniperus phoenicea.

This study explores the population structure, hybridization, and adaptation of Juniperus communis sensu lato in the context of its current habitat fragmentation, using inter-primer binding site markers and needle morphometry. Three native juniper taxa in Slovakia were analyzed: J. communis ssp. communis , J. communis ssp. nana , and their putative hybrid, J. communis nothovar. intermedia . The results reveal a moderate overall structure ( Φ PT  = 0.115, p  = 0.001), indicating high gene flow within ssp. communis and low gene flow between ssp. communis and ssp. nana . However, after correcting for non-neutral loci, the inter-subspecies differentiation dropped significantly, suggesting adaptive divergence despite substantial gene flow. This conclusion was further supported using admixture regression of needle morphometry and Φ PT – Q ST comparison. We show that adaptive genetic differentiation may play a more significant role than phenotypic plasticity in these traits, a key consideration in preventing outbreeding depression in conservation management. Importantly, we also provide evidence for intermediate admixture and distinct selection pressures within two populations of nothovar. intermedia (Stolica, Kralova Studna), which may qualify their recognition as evolutionarily significant units (ESUs).

Indaziflam was evaluated in Connecticut and Tennessee for weed control and safety of container-grown ornamental plants. Indaziflam was applied at 49, 98, or 196 g ha–1 to container-grown ornamental plants on an outdoor gravel pad and also applied preemergence or early postemergence to weeds in a greenhouse. Ornamental plants were treated twice annually in 2020 and 2021 in Connecticut, and in 2019 and 2020 in Tennessee, with approximately 6 wk between applications. Chinese pyramid juniper, common juniper, eastern hemlock, eastern white pine, and Norway spruce in Connecticut, and ‘Andorra Compacta’ creeping juniper and ‘Black Dragon’ Japanese cedar, ‘Blue Rug’ creeping juniper, and ‘Blue Pfitzer’ Chinese pyramid juniper in Tennessee were not injured with indaziflam regardless of the rate applied. Preemergence application of indaziflam reduced densities of creeping woodsorrel, hairy bittercress, giant foxtail, and large crabgrass by 72% to 100%, depending on the indaziflam rate applied, by 28 d after treatment (DAT). When applied early postemergence, indaziflam provided 97% to 99% control of creeping woodsorrel (1- to 2-leaf), fringed willowherb (4- to 6-leaf), hairy bittercress (cotyledon to 1-leaf), and mouse-ear chickweed (2- to 4-leaf) by 28 DAT. Compared with a nontreated control, the total fresh shoot biomass reduction was 86% to 100% and 78% to 100% following preemergence or postemergence applications. Indaziflam offers a new site of action with excellent safety and weed control in the tested ornamental plants. Nomenclature: Indaziflam; Giant foxtail, Setaria faberi Herrm.; hairy bittercress, Cardamine hirsute L.; Large crabgrass, Digitaria sanguinalis (L.) Scop.; Andorra Compacta creeping juniper, Juniperus horizontalis Moench; Black Dragon Japanese cedar, Cryptomeria japonica D. Don; Blue Rug creeping juniper, Juniperus horizontalis Moench; Blue Pfitzer Chinese pyramid juniper, Juniperus chinensis L.; Chinese pyramid juniper, Juniperus chinensis L.; Common juniper, Juniperus communis L.; Creeping woodsorrel, Oxalis corniculate L.; Eastern hemlock, Tsuga canadensis (L.) Carrière; eastern white pine, Pinus strobus L.; Norway spruce, Picea abies (L.) H. Karst.

Model–data comparisons of plant physiological processes provide an understanding of mechanisms underlying vegetation responses to climate. We simulated the physiology of a piñon pine–juniper woodland (Pinus edulis–Juniperus monosperma) that experienced mortality during a 5 yr precipitation-reduction experiment, allowing a framework with which to examine our knowledge of drought-induced tree mortality. We used six models designed for scales ranging from individual plants to a global level, all containing state-of-the-art representations of the internal hydraulic and carbohydrate dynamics of woody plants. Despite the large range of model structures, tuning, and parameterization employed, all simulations predicted hydraulic failure and carbon starvation processes co-occurring in dying trees of both species, with the time spent with severe hydraulic failure and carbon starvation, rather than absolute thresholds per se, being a better predictor of impending mortality. Model and empirical data suggest that limited carbon and water exchanges at stomatal, phloem, and below-ground interfaces were associated with mortality of both species. The model–data comparison suggests that the introduction of a mechanistic process into physiology-based models provides equal or improved predictive power over traditional process-model or empirical thresholds. Both biophysical and empirical modeling approaches are useful in understanding processes, particularly when the models fail, because they reveal mechanisms that are likely to underlie mortality. We suggest that for some ecosystems, integration of mechanistic pathogen models into current vegetation models, and evaluation against observations, could result in a breakthrough capability to simulate vegetation dynamics.

In order to propagate and regenerate the Juniperus excelsa L. in large quantities, this research was conducted to identify the appropriate mineral salt concentrations and plant growth regulators toward forest ecosystem sustainability. Different basal culture media including Olive Medium (OM), Murashige and Skoog (MS), Driver and Kuniyuki (DKW), Woody Plant Medium (WPM), ½ MS, and ¼ MS supplemented with 1 mg L -1 6-benzylaminopurine (BAP) and 0.1 mg L -1 indole-3-acetic acid (IAA) as plant growth regulators (PGR) were examined on the explants’ aerial organ growth, rooting and shoot proliferation. The experiment was carried out in a completely randomized design with three replicates and each replicate consisted of six samples. The results showed that the OM, DKW, and WPM culture media achieved the highest juniper regeneration of 100% when combined with BAP and IAA. The basic culture medium DKW produced the highest average number of shoots (8.05 shoots/explant) in the presence of 1 mg L -1 BAP and 0.1 mg L -1 IAA, however the highest shoot length (9.6 mm) observed in the DKW culture medium with no PGR. It is concluded that DKW and OM were the proper and most efficient culture medium for J. excelsa branch propagation and rooting, respectively.

Background: A central aim of island biogeography is to understand the colonization history of insular species using current distributions, fossil records and genetic diversity. Here, we analyze five plastid DNA regions of the endangered Juniperus brevifolia, which is endemic to the Azores archipelago. Methodology/Principal Findings: The phylogeny of the section Juniperus and the phylogeographic analyses of J. brevifolia based on the coalescence theory of allele (plastid) diversity suggest that: (1) a single introduction event likely occurred from Europe; (2) genetic diversification and inter-island dispersal postdated the emergence of the oldest island (Santa Maria, 8.12 Ma); (3) the genetic differentiation found in populations on the islands with higher age and smaller distance to the continent is significantly higher than that on the younger, more remote ones; (4) the high number of haplotypes observed (16), and the widespread distribution of the most frequent and ancestral ones across the archipelago, are indicating early diversification, demographic expansion, and recurrent dispersal. In contrast, restriction of six of the seven derived haplotypes to single islands is construed as reflecting significant isolation time prior to colonization. Conclusions/Significance: Our phylogeographic reconstruction points to the sequence of island emergence as the key factor to explain the distribution of plastid DNA variation. The reproductive traits of this juniper species (anemophily, ornithochory, multi-seeded cones), together with its broad ecological range, appear to be largely responsible for recurrent inter-island colonization of ancestral haplotypes. In contrast, certain delay in colonization of new haplotypes may reflect intraspecific habitat competition on islands where this juniper was already present.

To test the hypothesis that drought predisposes trees to insect attacks, we quantified the effects of water availability on insect attacks, tree resistance mechanisms, and mortality of mature piñon pine (Pinus edulis) and one-seed juniper (Juniperus monosperma) using an experimental drought study in New Mexico, USA. The study had four replicated treatments (40 × 40 m plot/replicate): removal of 45% of ambient annual precipitation (H2O−); irrigation to produce 125% of ambient annual precipitation (H2O+); a drought control (C) to quantify the impact of the drought infrastructure; and ambient precipitation (A). Piñon began dying 1 yr after drought initiation, with higher mortality in the H2O− treatment relative to other treatments. Beetles (bark/twig) were present in 92% of dead trees. Resin duct density and area were more strongly affected by treatments and more strongly associated with piñon mortality than direct measurements of resin flow. For juniper, treatments had no effect on insect resistance or attacks, but needle browning was highest in the H2O− treatment. Our results provide strong evidence that ≥ 1 yr of severe drought predisposes piñon to insect attacks and increases mortality, whereas 3 yr of the same drought causes partial canopy loss in juniper.

Strontium stannate nanorods (SrSnO 3 NRs) were synthesized in the present study via a green, sustainable, and cheap method with leaf extract from Juniperus communis L. UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray analysis (EDAX) were performed to investigate the SrSnO 3 NRs. The particle size distribution (PSD) of SrSnO 3 NRs characterized by using dynamic light scattering (DLS) analysis. The UV-visible spectra of the synthesized SrSnO 3 NRs showed an absorption peak at 279 nm. SEM images confirmed that SrSnO 3 NRs, which have an average size of about 29 nm, include a bunch of rod-like structure. In addition, the as-formed SrSnO 3 NRs demonstrated excellent antibacterial activity against the bacteria Staphylococcus aureus , Enterococcus faecalis , and Escherichia coli . The synthesized SrSnO 3 nanorods also exhibited a significant amount of antioxidant activity. It is also an attractive biocompatible choice for pharmacological and medical applications.

Tree features may modulate the sensitivity of radial growth to climate, leading to a nonuniform response. Age-related increases in climatic sensitivity have been observed repeatedly. Sex-related climatic sensitivity is also possible because of the long-term differential reproductive cost between the sexes. This study analysed the simultaneous effects of age and sex on the sensitivity of tree-ring growth to climate. Ring widths were measured from 50 female and 50 male Juniperus thurifera trees, 50-350 yr old, growing under a Mediterranean continental climate. Response functions were calculated based on tree-ring chronologies and monthly climatic records. Climatic sensitivity decreased with increasing age. Young trees (50-100 yr) were the most climatically sensitive to June-July precipitation, which affected growth positively. We found a significant interaction between age and sex in the climatic response of J. thurifera, with young females the most sensitive to summer water stress. Our results suggest that age-dependent climatic sensitivity can be determined by site-specific limiting environmental conditions and species-specific architectural and physiological adjustments during ontogeny. This study supports that the different ontogenetic stages of J. thurifera differ in their root structural traits and that sex-related sensitivity to summer drought may be attributable to less efficient water use by females.

Rising feed costs and recurring feed shortages necessitate the investigation into alternative and underutilized feed resources. Nutritional characteristics of species are either unknown or limited to leaves and ground material from small stems. Therefore, the objective was to quantify nutritional characteristics, 48-h true IVDMD (tIVDMD), microbial gas production, and secondary compound characteristics of entire woody plant material of 4 species-, , , and -at immature and mature stages of growth. Immature plants had greater CP concentrations and lower NDF concentrations ( < 0.001) than mature plants regardless of species. Mature plants also had greater ( < 0.001) concentrations of ADF compared with immature plants with the exception of . In general, immature , , and had greater ( < 0.02) tIVDMD and total 48-h and asymptotic gas production than mature plants. Immature and plants were more digested (tIVDMD; < 0.001) than immature and , but tIVDMD did not differ in mature plant material across species. Condensed tannins (CT) were greater ( < 0.001) in immature and than mature plants; differences in CT concentrations among immature species were also detected ( < 0.04). Volatile oil yields were similar across maturity and species with 1 exception: immature yielded more ( < 0.02) volatile oil than mature material. Volatile oil composition across species varied and contained a range of 65 to 70 terpene compounds. The dominant terpenes across species were generally greater ( < 0.05) in immature vs. mature plant material with the exception of . Labdane acids were negligible in , , and and greater in ( < 0.001). Ground material from mature juniper species, although inferior in nutritional quality compared with immature plants, is comparable to traditional low-quality roughage ingredients. Given that has been successfully fed in lamb feedlot diets, the similarities of , and suggest that all three species have potential to be effective roughage ingredients.