Acorus calamus, a perennial emergent herb, is highly valued for its ornamental appeal, water purification ability, and medicinal properties. However, there is a significant contradiction between the rapidly increasing demand for A. calamus and the diminishing wild resources. Understanding its geographical distribution and the influence of global climate change on its geographical distribution is imperative for establishing a theoretical framework for the conservation of natural resources and the expansion of its cultivation. In this study, 266 distribution records of A. calamus and 18 selected key environmental factors were utilized to construct an optimal MaxEnt model via the ENMeval package. We simulated the potential geographical distributions under current conditions and under three different climate scenarios (SSP126, SSP370, and SSP585) in the 2050s, 2070s, and 2090s. Additionally, we employed the jackknife method and response curves to identify the environmental factors with the greatest influence on the distribution of A. calamus, and their response intervals. The results indicate that the regularization multiplier (RM) of 3.5 and the feature combinations (FC) of linear (L), quadratic (Q), hinge (H), and product (P) are the optimal model parameter combinations. With these parameters, the model predictions are highly accurate, and the consistency of the results is significant. The dominant environmental factors and their thresholds affecting the distribution of A. calamus are the precipitation of the wettest month (≥109.87 mm), human footprint (≥5.39), annual precipitation (≥388.56 mm), and mean diurnal range (≤12.83 °C). The primary land use types include rivers and channels, reservoirs and ponds, lakes, urban areas, marshes, other constructed lands, rice fields, forested areas, and shrublands. Under current climate conditions, the suitable geographical distribution of A. calamus in China is clearly located east of the 400 mm precipitation line, with high- and low-suitability areas covering 121.12 × 10⁴ km², and 164.20 × 10⁴ km², respectively. Under future climate conditions, both high- and low- suitability areas are projected to increase significantly, whereas unsuitable areas are expected to decrease, with the centroid of each suitability zone shifting northward. This study provides a theoretical foundation for sustainable utilization, future production planning, and the development of conservation strategies for wild germplasm resources of A. calamus.

The effects of varieties, concentrations, and number of applications of plant growth retardants (PGRs) on the morphological, physiological, and endogenous hormones of Magnolia wufengensis L.Y. Ma et L. R. Wang were assessed to obtain the most suitable dwarfing protocol for M. wufengensis and to provide theoretical support and technical guidance for the cultivation and promotion of this species. One-year-old M. wufengensis ‘Jiaohong No. 2’ grafted seedlings served as the experimental materials. In the first part of the experiment, three PGRs (uniconazole, paclobutrazol, prohexadione calcium), three concentrations (500, 1000, 1500 ppm), and three applications (one, three, and five applications) were applied in dwarfing experiments to perform L9 (3⁴) orthogonal tests. In the second part of the study, dwarfing experiments were supplemented with different high uniconazole concentrations (0, 1500, 2000, 2500 ppm). Spraying 1500 ppm uniconazole five times achieved the best M. wufengensis dwarfing effect, related indicators of M. wufengensis under this treatment were better than other treatment combinations. Here, M. wufengensis plant height, internode length, scion diameter, and node number were significantly reduced by 56.9%, 62.6%, 72.8%, and 74.4%, respectively, compared with the control group. This treatment increased superoxide dismutase (SOD) activity by 66.0%, peroxidase (POD) activity by 85.0%, soluble protein contents by 43.3%, and soluble sugar contents by 27.6%, and reduced malondialdehyde (MDA) contents by 32.1% in leaves of M. wufengensis compared with the control. The stress resistance of M. wufengensis was enhanced. The treatment also reduced gibberellin (GA₃) levels by 73.0%, auxin (IAA) by 58.0%, and zeatin (ZT) by 70.6%, and increased (abscisic acid) ABA by 98.1% in the leaves of M. wufengensis. The uniconazole supplementation experiment also showed that 1500 ppm was the optimal uniconazole concentration. The leaves exhibited abnormalities such as crinkling or adhesion when 2000 or 2500 ppm was applied. Given the importance of morphological indicators and dwarfing for the ornamental value of M. wufengensis, the optimal dwarfing treatment for M. wufengensis was spraying 1500 ppm uniconazole five times.

Magnolia wufengensis is a newly discovered rare and endangered species endemic to China. The primary objective of this study is to find the most suitable species distribution models (SDMs) by comparing the different SDMs to predict their habitat distribution for protection and introduction in China under climate change. SDMs are important tools for studying species distribution patterns under climate change, and different SDMs have different simulation effects. Thus, to identify the potential habitat for M. wufengensis currently and in the 2050s (2041–2060) and 2070s (2061–2080) under different climate change scenarios (representative concentration pathways RCP2.6, RCP4.5, RCP6.0, and RCP8.5) in China, four SDMs, Maxent, GARP, Bioclim, and Domain, were first used to compare the predicted habitat and explore the dominant environmental factors. The four SDMs predicted that the potential habitats were mainly south of 40° N and east of 97° E in China, with a high distribution potential under current climate conditions. The area under the receiver operating characteristic (ROC) curve (AUC) (0.9479 ± 0.0080) was the highest, and the Kappa value (0.8113 ± 0.0228) of the consistency test and its performance in predicting the potential suitable habitat were the best in the Maxent model. The minimum temperature of the coldest month (−13.36–9.84 °C), mean temperature of the coldest quarter (−6.06–12.66 °C), annual mean temperature (≥4.49 °C), and elevation (0–2803.93 m), were the dominant factors. In the current climate scenario, areas of 46.60 × 10⁴ km² (4.85%), 122.82 × 10⁴ km² (12.79%), and 96.36 × 10⁴ km² (10.03%), which were mainly in central and southeastern China, were predicted to be potential suitable habitats of high, moderate, and low suitability, respectively. The predicted suitable habitats will significantly change by the 2050s (2040–2060) and 2070s (2060–2080), suggesting that M. wufengensis will increase in high-elevation areas and shift northeast with future climate change. The comparison of current and future suitable habitats revealed declines of approximately 4.53%–29.98% in highly suitable habitats and increases of approximately 6.45%–27.09% and 0.77%–21.86% in moderately and lowly suitable habitats, respectively. In summary, these results provide a theoretical basis for the response to climate change, protection, precise introduction, cultivation, and rational site selection of M. wufengensis in the future.

Magnolia wufengensis belongs to the Magnoliaceae family. Its variation-rich flowers (tepal number from 9 to 46, tepal color from pink to bright red) and excellent wood characteristics (strong, straight, texture) have important ornamental and economic value (Duan et al. 2019; Luyi et al. 2006). M. wufengensis is popularly cultivated in parks, courtyards, mountains, and along roadsides. In May 2020, leaf spot symptoms were observed on over 85% of M. wufengensis in Yuyangguan Township, Wufeng County, Hubei Province (110.60°E, 30.21°N). The damaged area was over 18.7 hectares. Early symptoms began as small brown spots with a light-yellow halo. Gradual lesions expanded, and the center was withered, gray, and necrotic with a dark brown border. Eventually, several spots combined with larger irregular lesions, turning the leaves yellow and causing them to fall off. The border of lesions and healthy tissues were cut into small pieces (5×5 mm), and surface sterilized with 1% sodium hypochlorite solution for three minutes, rinsed three times with sterile water, and plated on potato dextrose agar (PDA) medium at 25±2 °C with a 12h photoperiod under fluorescent lighting. Pure isolates (MCS1228.1, MCS1228.4, MCS1228.9) were gray to pale grayish, and their average growth rate was 10.5±1.23 mm/day. Conidiophores were hyaline, aseptate, branched. Conidia were hyaline, aseptate, cylindrical, and 14.00 to 25.17 × 4.74 to 6.56 μm in size (average 17.48 × 5.58 μm) (n=50). Appressoria were brown and showed multivariate shape. The morphological characteristics of the isolates corresponded to the description given for Colletotrichum fructicola (Liu et al. 2015). Molecular identification was accomplished through amplification of the internal transcribed spacer (IST), actin (ACT), calmodulin (CAL), chitin synthase (CHS-1) glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2) genes (Fu et al. 2018). The ITS (OL800580.1, OL800581.1, OL800582.1), ACT (GenBank accession No. OL873155- OL873157), CAL (GenBank accession No. OL873158- OL873160), CHS-1 (GenBank accession No. OL873161- OL873163), GAPDH (GenBank accession No. OL873164- OL873166) and TUB2 (GenBank accession No. OL873167- OL873169) sequences were deposited in GenBank. A Bayesian inference phylogenetic tree based on multilocus sequences was constructed, and the sequences of the 3 isolations showed the same homology with C. fructicola (Fu et al. 2018). To fulfill Koch's postulates, 30 potted seedlings were inoculated with 1×10^6 conidia/ml suspension of each isolate by spraying the leaves, and 30 potted seedlings were sprayed with sterile distilled water as control. Inoculated and control plants were kept in a greenhouse with 25/15°C (day/night) temperature and 80% relative humidity. In addition, 30 healthy detached leaves free of pests and diseases were washed three times with sterile distilled water, air-dried, and artificially inoculated using a 6 mm (diameter) PDA medium (5 days incubation) with mycelium. 30 leaves were inoculated with sterile PDA medium as control. All leaves were sprayed with sterile water every 24 hours, covered with plastic wrap, and incubated at 25±2 °C, 100% humidity. The experiment was repeated three times. Similar symptoms to those found initially were both observed on all the inoculated potted seedlings and detached leaves after 14 days and 5 days post inoculation (dpi), respectively. Whereas the controls remained symptomless. The reisolated pathogens from symptomatic tissues were identical to the original isolates. In this study, isolated fungi associated with M. wufengensis leaf spot were identified as C. fructicola based on morphological and multiloci phylogenetic analyses, and Koch's postulates. Colletotrichum species are important plant pathogens and cause diseases in a wide variety of woody and herbaceous plants (Cannon et al. 2012). C. fructicola has been identified as a responsible pathogen for apple (Casanova et al. 2016), Fatsia japonica (Shi et al. 2017), and Rubus corchorifolius (Wu et al. 2021) leaf spot. To our knowledge, this is the first report of C. fructicola causing leaf spot in M. wufengensis in China. This research may contribute to the development of management strategies for this disease.

Currently, the number of urban garden green spaces (GGSs) being constructed in Beijing is increasing, and their high water resource demands contradict the severe water shortage situation in Beijing that is restricting urban construction and economic development. This has created an urgent need to build water-saving GGSs. This study analyzed and compared the daily/annual water consumption of 79 common plants in Beijing, and low-water-consumption (LWC) trees, shrubs and herbs were selected; additionally, the total annual water consumption (TAWC) of all plants in the built-up areas of all 16 districts in Beijing was calculated according to the result of the eighth general survey of landscaping resources in Beijing. The results are as follows: (1) fifteen LWC tree species were selected from among 25 species, and the average daily water consumption (DWC) was <1.09 kg·m⁻²; (2) nineteen LWC shrubs were selected from among 35 shrubs, and the average DWC was <1.17 kg·m⁻²; (3) eleven LWC herbs were selected from among 19 herbs, and the AWC was <460.3 kg·m⁻²; (4) the TAWC of all trees, shrubs and herb plants in the Beijing GGSs was 1.104 × 10⁹, 0.139 × 10⁹, and 0.16 × 10⁹ m³, respectively. Based on the above results, it was estimated that the TAWC of all plants in the built-up areas of all 16 districts in Beijing is approximately 1.403 × 10⁹ m³. These findings provide a better understanding of the water consumption of GGS plants in cities in semiarid and semihumid climates and can be used to help select LWC greening plants that can reduce water consumption when expanding green areas in cities.

Litsea cubeba (Lour.) Pers. is an important economic tree. We aimed to explore the phenotypic diversity of wild L. cubeba provenances from Jiangxi province and identify the germplasms with desirable characteristics. Nest variance analysis, multiple comparisons, correlation analysis, path analysis, redundancy analysis, and cluster analysis were conducted to compare the phenotypes of 526 wild L. cubeba trees from 27 provenances. We detected significant differences in the growth traits, fruit traits, and essential oil (EO) content of L. cubeba provenances, as well as significant differences in tree height, thousand seed dry weight, and the proportion of five essential oil components (citral, neral, geranial, D-limonene, and citronellal) within the provenances. The fresh fruit yield (FFY) was mainly determined by the ground diameter and the annual average minimum temperature. The EO content was mainly affected by the water content, annual average temperature, longitude, and latitude. The proportion of citral (CitrP) was negatively affected by extreme low temperatures. Four individual L. cubeba trees had a high FFY of over 10.00 kg·tree⁻¹. Two trees had a high EO content exceeding 5%, with their CitrP over 80%. The provenances with high FFY were Guixi and Yushan (2.65 kg·tree⁻¹; 2.89 kg·tree⁻¹). The provenances with a high EO content of about 4.00% were Dayu, Yudu, Ji’an, Xinfeng, and Yushan. The provenance with the highest CitrP level (80.61%) was Ningdu.