Soundscape Preference of Urban Residents in China in the Post-pandemic Era

This research aims to explore the reality of the soundscape preferences of Chinese urban residents in general public landscape in the post-pandemic era, and then to propose design recommendations to meet the practical needs of people’s preferences for landscape—especially soundscapes—in the post-pandemic era. In this study, we utilized the subjective evaluation method to conduct an online questionnaire in 29 Chinese provinces which experienced severe pandemic caseloads and collected 860 valid responses. This study revealed people’s preference for landscape and soundscape in the post-pandemic era. We further studied the correlation between landscape preference and soundscape preference, analyzed the influence of living conditions on soundscape preference, founded the effects of personal characteristics and living conditions on soundscape preference, and explored the strongest influence factors on soundscape preference through the establishment of automatic linear model. The results revealed a positive correlation between life happiness and soundscape preference, whereas wearing masks significantly reduced soundscape perception ratings and people who have been vaccinated are more tolerant of various noises. Moreover, based on these analysis results, the design recommendations on landscape (overall landscape, plant, and tour space), soundscape construction of caring for vulnerable groups (teenagers and children, elderly people, and disabled and unhealthy) has been discussed.

First Report of Anthracnose Caused by Colletotrichum fructicola on Loropetalum chinense in China

Loropetalum chinense Oliv. (Hamamelidaceae), an evergreen shrub or small tree, is widely used as a bonsai and landscape plant because of its aesthetic value. In addition, it has medicinal value, its leaves, flowers and roots can be used to treat diarrhea, coughs, hemorrhaging and burn (Zhang et al. 2013). In October 2020, leaf spot symptoms were observed on L. chinense distributed in Meiling Scenic Spot of Nanchang, Jiangxi Province, China (28.78°N, 115.83°E). We surveyed about 500 m2 of the mountain area which holds about 60 trees of L. chinense, with an incidence up to 20%. Initially, small gray-brown spots with dark brown edges appeared on the leaf surface, becoming large circular or irregular brown necrotic lesions over time. To isolate the pathogen, ten leaves of infected tissues were cut into 4 mm2 pieces, and surface disinfected with 75% ethanol for 30s and 1% hypochlorite for 1 min, rinsed three times with sterile water, plated on potato dextrose agar (PDA), and incubated at 25°C in the dark for 5 to 7 days. Five isolates with similar morphological characteristics were obtained. Conidia were hyaline, aseptate, smooth-walled, cylindrical with obtuse to slightly rounded ends, and their dimensions varied from 8.57 to 15.80 × 1.56 to 4.65 μm (n = 20). The morphological characteristics of the isolates matched the descriptions of Colletotrichum gloeosporioides species complex (Cai et al. 2009; Weir et al. 2012; Liu et al. 2015). For molecular identification, two representative isolates (JAUCC L003 and JAUCC L004) were selected for genomic DNA extraction, and the internal transcribed spacer (ITS), partial calmodulin (CAL), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and actin (ACT) were amplified, using primer pairs ITS1/ITS4, CL1C/CL2C, CHS-79F/CHS-345R, GDF1/GDR1, and ACT-512F/ACT-783R, respectively (White et al. 1990; Weir et al. 2012; Yang et al.2020). The sequenced loci (GenBank accession nos. ITS: MZ054401, MZ054400; CAL: MZ056750, MZ056754; CHS-1: MZ056751, MZ056755; GAPDH: MZ056752, MZ056756; ACT: MZ056753, MZ056757) exhibited up to 99% homology with corresponding sequences of C. fructicola Prihast., L. Cai & K.D. Hyde strains (GenBank accession nos. LC494271, MN525833, MN525854, MN525875 and MN525814). Concatenated sequences of the five genes were used to conduct a phylogenetic analysis using Maximum-Likelihood (ML) method in MEGA7. The isolates were identified as C. fructicola based on morphology and a multigene phylogenetic analyses. Pathogenicity of one representative isolate (JAUCC L003) was tested indoor by inoculating the top wounded leaves of six healthy L. chinense plants, rather than inoculating unwounded leaves due to the low incidence. Three leaves from each of three plants were punctured with flamed needles and sprayed with a conidial suspension (1 × 106 conidia/ml), and three leaves from each of other three plants were wounded and inoculated with mycelial plugs (5 × 5 mm3). Mock inoculations were used as controls with sterile water and PDA plugs on three leaves each. Treated plants were incubated in an artificial climate box at 25 °C, 90% relative humidity, with a 12-h photoperiod. All leaves inoculated with conidial suspension and mycelial plugs produced similar symptoms as described above 10 days postinoculation, whereas the mock inoculated plants remained asymptomatic. The fungus isolated from inoculated leaves was identical to the original pathogen on account of morphological and molecular data, confirming Koch's postulates, but not from the mock inoculated plants. Anthracnose disease caused by C. fructicola has been reported affecting numerous plants worldwide, including cotton, coffea, grape, citrus, mango, apple, pear, and cassava, among others (Guarnaccia et al. 2017, Oliveira et al. 2018). To our knowledge, this is the first report of C. fructicola causing anthracnose on L. chinense in China. This disease is significant concern in horticulture due to its impact on the aesthetics of ornamentals used in landscape plantings.

Differential Tolerance to Calonectria pseudonaviculata of English Boxwood Plants Associated with the Complexity of Culturable Fungal and Bacterial Endophyte Communities

Isolated boxwood endophytes have been demonstrated to effectively protect boxwood plants from infection by Calonectria pseudonaviculata (Cps). However, the roles of endophytes as communities in plant defense are not clear. Here, we demonstrated differential tolerance to Cps of English boxwood (Buxus sempervirens ‘Suffruticosa’), an iconic landscape plant and generally regarded as highly susceptible, and its link to endophyte complexity. Fifteen boxwood twig samples were collected in triplicates from three historic gardens—Colonial Williamsburg, George Washington’s Mount Vernon and River Farm, and Virginia Tech’s research farm in Virginia Beach in the summer and fall of 2019. A portion of individual samples was inoculated with Cps under controlled conditions. Significant differences in disease severity were observed among samples but not between the two seasons. Examining the endophyte cultures of the summer samples revealed that bacterial and fungal abundance was negatively and positively correlated with the disease severity. Nanopore metagenomics analysis on genomic DNA of the tolerant and susceptible group representatives confirmed the associations. Specifically, tolerant English boxwood plants had an endophyte community dominated by Bacilli and Betaproteobacteria, while susceptible ones had a distinct endophyte community dominated by Gammaproteobacteria, Actinobacteria, and diverse fungi. These findings may lead to boxwood health management innovations—devising and utilizing cultural practices to manipulate and increase the abundance and performance of beneficial endophytes for enhanced boxwood resistance to Cps.

Herbaceous perennial ornamental plants can support complex pollinator communities

Human-designed landscapes can host diverse pollinator communities, and the availability of floral resources is central to supporting insect biodiversity in highly modified environments. However, some urban landscapes have relatively few pollinator-attractive plant species and management in urban environments rarely considers the function of these plants in generating and supporting a stable ecological community. Evaluations of 25 cultivars within five commercially popular herbaceous perennial ornamental plant genera (Agastache, Echinacea, Nepeta, Rudbeckia, and Salvia) revealed variation in the total and proportional abundance of visitors attracted. These varieties supported multiple pollinator functional groups, however bees were the primary visitors to in this system. Cultivars were assessed according to their function within a plant–pollinator network. Comparisons of artificial networks created with the six most attractive and six least attractive cultivars demonstrated that a planting scheme using the most attractive cultivars would attract nearly four times as many bee species, including several specialists and rare species. Plant diversity in the landscape was correlated with abundance and diversity of pollinator visitors, demonstrating that community context shapes a plant’s relative attractiveness to pollinators. We conclude that herbaceous perennial cultivars can support an abundance and diversity of pollinator visitors, however, planting schemes should take into consideration the effects of cultivar, landscape plant diversity, floral phenology, floral area, and contribution to a stable ecological community.

Investigating Phragmites Australis Response to Copper Exposure Using Physiologic，FTIR and Metabolomic Approaches

Background and aim Phragmites australis is a landscape plant with phytoremediation functions that is widely planted worldwide. However, little is known about the metabolomic background of the resistance mechanisms of Phragmites to heavy metals during its growth and development. Methods Here, we performed copper stress studies on Phragmites and monitored physiological indicators such as malondialdehyde (MDA) and electrolyte leakage (EL). In addition, FTIR was used to study chemical composition changes in the roots, stems and leaves of Phragmites seedlings under excessive copper stress. Furthermore, LC-MS technology combined with metabolomics data processing software was used to analyze the metabolic profile of samples.Result Copper contributed to the accumulation of MDA and EL. And the results of FTIR showed that the antioxidant effects of flavonoids and amino acids can be used by Phragmites leaf tissue to improve the tolerance of copper under 5 mg/L concentration. Further, the results of metabolomics reflected that Phragmites can improve its resistance to copper by increasing the accumulation of arginine and ayarin in the body. The former is accumulated through two pathways: the citrulline decomposition and conversion pathway and the circular pathway composed of ornithine, citrulline, L-Argininosuccinate and arginine. The latter is synthesized through the quercetin methylation pathway.Conclusion This study provides insights into the resistance mechanism and repair performance of Phragmites and other plant accumulators in response to copper stress.

Mobius Assembly for Plant Systems highlights promoter-terminator interaction in gene regulation

Plant synthetic biology is a fast-evolving field that employs engineering principles to empower research and bioproduction in plant systems. Nevertheless, in the whole synthetic biology landscape, plant systems lag compared to microbial and mammalian systems. When it comes to multigene delivery to plants, the predictability of the outcome is decreased since it depends on three different chassis: E.coli, Agrobacterium, and the plant species. Here we aimed to develop standardised and streamlined tools for genetic engineering in plant synthetic biology. We have devised Mobius Assembly for Plant Systems (MAPS), a user-friendly Golden Gate Assembly system for fast and easy generation of complex DNA constructs. MAPS is based on a new group of small plant binary vectors (pMAPs) that contains an origin of replication from a cryptic plasmid of Paracoccuspantotrophus. The functionality of the pMAP vectors was confirmed by transforming the MM1 cell culture, demonstrating for the first time that plant transformation is dependent on the Agrobacterium strains and plasmids; plasmid stability was highly dependent on the plasmid and bacterial strain. We made a library of new short promoters and terminators and characterised them using a high-throughput protoplast expression assay. Our results underscored the strong influence of terminators in gene expression, and they altered the strength of promoters in some combinations and indicated the presence of synergistic interactions between promoters and terminators. Overall this work will further facilitate plant synthetic biology and contribute to improving its predictability, which is challenged by combinatorial interactions among the genetic parts, vectors, and chassis.

A Digital Framework to Predict the Sunshine Requirements of Landscape Plants

Knowledge of the sunshine requirements of landscape plants is important information for the adaptive selection and configuration of plants for urban greening, and is also a basic attribute of plant databases. In the existing studies, the light compensation point (LCP) and light saturation point (LSP) have been commonly used to indicate the shade tolerance for a specific plant; however, these values are difficult to adopt in practice because the landscape architect does not always know what range of solar radiation is the best for maintaining plant health, i.e., normal growth and reproduction. In this paper, to bridge the gap, we present a novel digital framework to predict the sunshine requirements of landscape plants. First, the research introduces the proposed framework, which is composed of a black-box model, solar radiation simulation, and a health standard system for plants. Then, the data fitting between solar radiation and plant growth response is used to obtain the value of solar radiation at different health levels. Finally, we adopt the LI-6400XT Portable Photosynthetic System (Li-Cor Inc., Lincoln, NE, USA) to verify the stability and accuracy of the digital framework through 15 landscape plant species of a residential area in the city of Wuhan, China, and also compared and analyzed the results of other researchers on the same plant species. The results show that the digital framework can robustly obtain the values of the healthy, sub-healthy, and unhealthy levels for the 15 landscape plant species. The purpose of this study is to provide an efficient forecasting tool for large-scale surveys of plant sunshine requirements. The proposed framework will be beneficial for the adaptive selection and configuration of urban plants and will facilitate the construction of landscape plant databases in future studies.