Interactions between plants and coexisting microorganisms have significant impacts on plant growth, development, and health. Human domestication has resulted in significant differences between modern crops and their wild ancestors in physiological and genetic characteristics and growth environment, which will inevitably affect the interaction between crops and their microbiomes. Understanding the impact of domestication on the diversity and community structure of microbiome and the mechanisms involved is an important theoretical basis for application of microbiome during crop improvement and breeding. In this review, we summarize the research progress of the effects of domestication on the community composition and diversity of root and shoot microbiome (bacteria and fungi) in crops. We also analyze the involved action pathways in shaping crop microbiomes by domestication, considering the domestication effect on crop morphology, root configuration, exudates and other physiological characteristics, and the change in growth environment. The research directions that need to be focused on in this field were proposed.

Aims Canopy gaps are a vital part of forest regeneration and succession. This paper aims to reveal the sources of functional trait variations and their relative contributions under forest canopy gaps. This will help to clarify the response of the plants to canopy gaps.
Methods The study was conducted in a natural forest of Castanopsis kawakamii in the central subtropical zone. Nine permanent plots with different sizes were set up under canopy gaps of this forest. The relative contributions of the gaps, species, and individuals to leaf trait variations were investigated using variance decomposition. Linear regression was used to analyze the importance of community mean trait variation and inter- and intraspecific trait variation among the different sizes of canopy gaps.
Important findings The variations of specific leaf area, leaf dry matter content, leaf thickness, and chlorophyll content of plants under canopy gaps were dominated by interspecific trait differences. Leaf nitrogen content was mainly varied within species, while the leaf phosphorus content was most affected by the size of canopy gap. The leaf phosphorus content had a significant positive correlation with gap size. This correlation may be mediated by the positive effect of soil temperature and hydrolyzed nitrogen and the negative effect of available phosphorus content. With the increase of canopy openness, the change of community phosphorus content was mainly caused by intraspecific trait variation, in which the dominant species played an important role. In conclusion, plant functional traits were still dominated by interspecific trait variation (41% on average) in the Castanopsis kawakamii natural forest, but the changes in community traits along the gap size gradients were mainly originated from intraspecific trait variation, which responded to the environmental changes through plant phenotypic plasticity, especially for dominant species.

Aims The objectives were to reveal the response patterns of plant species diversity and above-ground biomass to nutrients addition and to clarify their relationships in alpine grasslands of Tianshan Mountains.
Methods The nitrogen (N), phosphorus (P) and potassium (K) addition experiments were conducted in Tianshan alpine grasslands. The single factor effects and the interaction effects on plant species diversity and above-ground biomass were studied from 2019 to 2020.
Important findings 1) Nutrient addition reduced plant species diversity of local community. Especially, the addition of N + P, N + K and N + P + K showed significant effects, suggesting that the decrease of soil niche dimension caused by multiple-nutrient addition was an important reason for local species loss. 2) Nutrient addition significantly increased above-ground biomass of local plant communities, with the highest above-ground biomass being found under N + P + K treatment, indicating that N was the first limiting resource, P and K became the limiting resources after N limiting was alleviated. 3) There was a negative linear regression between species diversity and above-ground biomass following two years of nutrient addition, which indicated that the dominant species but not species diversity determined above-ground biomass at our study site.

Aims Plant phenology is an important indicator of ecosystem response to climate change, and it is also a central parameter for modelling plant productivity and vegetation dynamics. However, it remains unclear whether inner-annual, intra-annual, inter-species or inter-habitat variabilities exist in the response of plant phenology to environmental changes.
Methods Here we investigated the effects of long-term (>10 years) warming and nitrogen (N) addition on plant phenology in a temperate desert steppe. We used the phenological scoring observation method and Richards growth curve fitting method to monitor phenological shifts of three dominant species, Stipa breviflora, Artemisia frigida and Kochia prostrata, in the 11th, 12th and 13th treatment year.
Important findings We found that the flowering time ranged from the 129th to the 145th days of a year for S. breviflora, from the 230th to the 248th days for A. frigida, and from the 194th to the 222th days for K. prostrata. Warming and N addition tended to advance the flowering time of S. breviflora and K. prostrata, but tended to delay the flowering time of A. frigida. The fruiting time ranged from the 134th to the 148th days for S. breviflora, from the 241th to the 260th days for A. frigida, and from the 207th to the 231th days for K. prostrata. Warming and N addition tended to advance the fruiting time of S. breviflora and K. prostrata, but tended to delay that of A. frigida. The reproductive growth period lasted for 12 to 25 days for S. breviflora, 48 to 55 days for A. frigida, and 45 to 77 days for K. prostrata. Warming and N addition shortened the reproductive growth period for S. breviflora, but prolonged that period for A. frigida and K. prostrata.

Aims Mulberry (Morus alba) trees are known to be strongly water-tolerant. This study aims to understand flooding stress affects on mulberry’ non-structural carbohydrates and growth hormone.
Methods This study conducted an indoor simulated water flooding experiment using triennial potted mulberry saplings which were divided into four groups by different water conditions: the control group (CK), root submerged group (GY), shallowly submerged group (QY) and deep submerged group (SY). The content of non-structural carbohydrate (soluble sugar and starch) and endogenous growth hormone (ethylene, abscisic acid and gibberellin) in mulberry’ leaves were recorded regularly.
Important findings The research result suggested: (1) Flooding stress promoted endogenous chemical reactions within leaves of mulberry, resulting in increased content of soluble sugar in leaves. After 75 days of submergence, the content of soluble sugar in leaves of all groups (GY, QY and SY) increased by 182.18%, 170.21% and 94.16%, respectively compared with no-submergence conditions flooding; the difference was significant and the content was significantly higher than that of the CK. Under flooding stress, the leaf starch content did not change significantly from 0-50 days. After 75 days of submergence, the starch content of all groups (GY, QY and SY) increased by 290.84%, 244.65% and 130.04% compared with that at the 50 days; the difference was significant and the content was significantly higher than that of the CK group in the same period. (2) Flooding stress resulted in a significant increase in the content of ethylene and gibberellin in mulberry’ leaves. After 75 days of submergence, the content of ethylene in GY and SY increased by 62.80% and 26.78%, respectively compared with that no-flooding; the content of gibberellin in GY, QY and SY increased by 27.48%, 18.02% and 25.04%, respectively, suggesting significant difference. With the increased duration of submergence, the content of ethylene and gibberellin in GY and SY also increased, while the content of ethylene and gibberellin in QY first increased and then decreased but was still higher than the content non-flooding at the beginning of the experiment. Under flooding stress, the content of abscisic acid in leaves of all groups increased with the depth of submergence. After 75 days of submergence, the content of abscisic acid in QY and SY increased by 19.20% and 36.16%, respectively compared with that on day zero; the content of abscisic acid in GY did not change significantly, demonstrating the strongest resistance to submergence. Our research results suggest that mulberry are a species with strong resistance to submergence and can adapt to flooding stress by regulating the content and allocation of non-structural carbohydrates (soluble sugar and starch) and accumulating endogenous hormones such as ethylene, gibberellin and abscisic acid.

Aims With fast urbanization in China, ground-level ozone (O₃) has become the major atmospheric pollutant in summer. It was documented that O₃ enters leaves through stomata, inhibits photosynthesis, and alters the carbon and water cycles in terrestrial ecosystems. However, few studies have investigated the key parameters of photosynthetic and stomatal conductance models in response to elevated O₃ concentration.
Methods In this study, plants of four common tree species (Camellia sinensis, Acer negundo, Koelreuteria paniculata and Quercus mongolica) were exposed to two O₃ treatments (CF, charcoal-filtered air; E-O₃, ambient air + 60 nmol·mol^-1 O₃) in open top chambers. The effects of elevated O₃ concentration on key parameters of photosynthetic and stomatal conductance models were explored using data from leaf gas exchange measurements.
Important findings Our results indicated that elevated O₃ concentration significantly decreased the light-saturated photosynthesis and mesophyll conductance in the four species. However, species showed distinct responses of the maximum rate of Rubisco carboxylation and the maximum rate of electron transport to elevated O₃ concentration. The response of stomatal conductance to O₃ was also different among species. We found that elevated O₃ concentration significantly increased the slope parameters (g₁) of Q. mongolica and A. negundo; however, the intercept parameter of stomata model in C. sinensis was decreased in A. negundo. The intrinsic water- use efficiency of the four species was negatively correlated with g₁ across O₃ treatments. All in all, elevated O₃ concentration significantly affected key parameters of the photosynthetic and stomatal conductance models. This study could provide the foundation and support for improving the accuracy of terrestrial ecosystem models under elevated O₃ concentration.

Aims Forest litter are the main sources of soil humic substances, and different litter types can have differential effects on the formation and composition of soil humic substances. The aim of this study was to determine how variations in litter input would affect the dynamics of soil humic substances in subalpine forests of western Sichuan.
Methods A field in-situ litter manipulation experiment incorporating litter removal was established on sites of coniferous, broad-leaved, and mixed coniferous and broad-leaved forest stands. Measurements were made on the contents of soil extractable humic substances, humic acid, and fulvic acid; ratios of humic acid to fulvic acid and humic acid to humic substances were also computed.
Important findings The contents of extractable humic substances, humic acid and fulvic acid of soils varied significantly among forest types. The extractable humic substances content followed a descending order of coniferous forest > mixed coniferous and broad-leaved forest > broad-leaved forest, and the humic acid content of mixed coniferous and broad-leaved forest > coniferous forest > broad-leaved forest, and the fulvic acid content of coniferous forest > broad-leaved forest > mixed coniferous and broad-leaved forest. Fulvic acid was the predominant fraction of soil humic substances in all the three forest types. Time of measurements also significantly affected the contents of extractable humic substances, humic acid and fulvic acid, with an increasing trend for up to 1.5-year followed by decreases thereafter. With few exceptions, litter removal generally reduced the contents of extractable humic substances, humic acid and fulvic acid. The ratios of humic acid/fulvic acid and humic acid/extractable humic substances indicate low degree of humification for all the three forest types, which followed a descending order of mixed coniferous and broad-leaved forest > broad-leaved forest > coniferous forest. Litter removal improved the humic substances quality in the broad-leaved and mixed coniferous and broad-leaved forests to some extent. Correlation analysis showed significantly positive correlations of soil extractable humic substances with soil organic carbon, total nitrogen and soil water content, and a significantly negative correlation with temperature. In summary, short-term litter removal reduced the soil humic substances content, with differential effects by different litter types. We draw conclusion that the dynamics of soil humic substances are comprehensively regulated by litter type and environmental factors. Therefore, the impact of litter changes on soil humic substances needs further long-term research.

Aims Responses of soil carbon (C), nitrogen (N), and phosphorus (P) contents and their stoichiometric ratios to climatic variables (mean annual precipitation (MAP) and mean annual air temperature (MAT)) along soil depths are important for understanding the effects of climate change on terrestrial ecosystem functions.
Methods To explore the responses of soil C, N, and P contents and their stoichiometric ratios along soil profile to MAP and MAT at a regional scale, we investigated these variables for four soil layers (0-20, 20-40, 40-60, and 60-80 cm) at 44 sites in grasslands on the Mongolia Plateau.
Important findings (1) Soil C and N contents decreased while soil P did not change with increasing soil depth. Soil C:P and N:P decreased while soil C:N was relatively stable with increasing soil depth. (2) Soil C, N, and P contents, as well as C:P and N:P, were positively correlated with MAP, but negatively correlated with MAT. Soil C:N was negatively correlated with MAP but did not correlate with MAT. The correlations between climate variables and soil C, N, and P contents and their stoichiometric ratios were weakened with increasing soil depth. (3) The effect of MAP or MAT on soil C, N, and P contents and their stoichiometric ratios were different among four soil depths. The total interpretation of the variations in soil C, N, and P contents and their stoichiometric ratios explained by MAP or MAT decreased with increasing soil depth. These results indicate that climatic variables had a top-down regulation on soil C, N, P contents and their stoichiometric ratios, and the effect of MAP was more important than that of MAT on soil C, N, P contents and their stoichiometric ratios in grasslands on the Mongolia Plateau.

Aims Catalysis associated with extracellular enzymes are closely related to nutrient circulation and energetic flow in soils. Changes of global climate and land use have resulted in different degrees of death of moss-dominated biological soil crusts (BSCs), yet there is still little knowledge of how moss mortality influences the nutrient cycling in the topsoil of a temperate desert.
Methods In this study, we measured the enzyme activities related to carbon, nitrogen and phosphorus cycling in different soil layers (0-2, 2-5, 5-10, 10-20 cm) under living and dead mosses in a desert in Gurbantünggüt, Xinjiang, China.
Important findings We found that moss death had a significant effect on the activities of β-glucosidase, peroxidase, polyphenol oxidase, urease, nitrate reductase, phytase and alkaline phosphatase; these enzyme activities decreased with the increase of soil depth. The moss death decreased phytase activity, and increased enzyme activities related to carbon, nitrogen and phosphorus cycling. The results of correlation analyses showed that the carbon- and nitrogen-related enzyme activities were positively correlated with soil organic carbon, total nitrogen, NO₃^--N and NH₄⁺-N contents, and negatively correlated with pH, whereas the phytase and alkaline phosphatase activities had no significant correlation with total phosphorus and available phosphorus contents. In summary, the moss death in the temperate desert changed soil enzyme activities and accelerated soil nutrient cycling in a relatively short time.

Ephedra rhytidosperma is an endemic and endangered plant in East Alxa, and its community is one of the unique desert plant communities in the Helan Mountain. In this paper, we investigated 16 plots of the E. rhytidosperma community in 2019 and analyzed its flora characteristics, applied TWINSPAN to classify community types. Results showed that: 1) The species composition of E. rhytidosperma community was dominated by Gramineae, Compositae, Leguminosae and Zygophyllaceae, belonging to 13 families, 24 genera and 27 species. 2) The main life forms of E. rhytidosperma community were perennial herbs (44.44%) and shrubs (29.63%); the main floristic geographic elements were Palaeo-Mediterranean element (44.44%) and East Asia element (33.33%); the main ecological types of water were xerophyes (40.74%) and super-xerophytes (37.04%). 3) Based on the life forms and species composition, the E. rhytidosperma communities were divided into two major Association Groups. Ephedra rhytidosperma - Semi-Shrub Desert and Ephedra rhytidosperma - Herb Desert, which were further divided into 3 Associations: Ephedra rhytidosperma - Convolvulus tragacanthoides - Lespedeza davurica Semi-Shrub and Herb Desert, Ephedra rhytidosperma - Convolvulus tragacanthoides - Ptilagrostis pelliotii Semi-Shrub and Herb Desert and Ephedra rhytidosperma - Ptilagrostis pelliotii Semi-Shrub and Herb Desert.

The compiling protocols of Vegegraphy of China published earlier provided standards and guidelines for the compilation of Vegegraphy of China. In this study, we interpreted, revised and supplemented the protocols in view of some specific issues and deficiencies encountered during the subsequent compilation processes. We reaffirmed the term “Vegetation type” as a way to identify Volumes and Issues of the Vegegraphy of China. We emphasized the description of quantitative characteristics of the medium- and/or lower-level vegetation classification units, and we proposed to review and accept the community types recorded in literatures. In addition, we further elucidated the importance of the quantitative classification method as a way to support the vegetation classification scheme. These supplements and revisions, together with the previous protocols, constitute the basis and standard for compiling the Vegegraphy of China.