Decoupled response of microbial taxa and functions to nutrients: The role of stoichiometry in plantations.

The resource quantity and elemental stoichiometry play pivotal roles in shaping belowground biodiversity. However, a significant knowledge gap remains regarding the influence of different plant communities established through monoculture plantations on soil fungi and bacteria's taxonomic and functional dynamics. This study aimed to elucidate the mechanisms underlying the regulation and adaptation of microbial communities at the taxonomic and functional levels in response to communities formed over 34 years through monoculture plantations of coniferous species (Japanese larch, Armand pine, and Chinese pine), deciduous forest species (Katsura), and natural shrubland species (Asian hazel and Liaotung oak) in the temperate climate. The taxonomic and functional classifications of fungi and bacteria were examined for the mineral topsoil (0-10 cm) using MiSeq-sequencing and annotation tools of microorganisms (FAPROTAX and Funguild). Soil bacterial (6.52 ± 0.15) and fungal (4.46 ± 0.12) OTUs' diversity and richness (5.83*103±100 and 1.12*103±46.4, respectively) were higher in the Katsura plantation compared to Armand pine and Chinese pine. This difference was attributed to low soil DOC/OP (24) and DON/OP (11) ratios in the Katsura, indicating that phosphorus availability increased microbial community diversity. The Chinese pine plantation exhibited low functional diversity (3.34 ± 0.04) and richness (45.2 ± 0.41) in bacterial and fungal communities (diversity 3.16 ± 0.15 and richness 56.8 ± 3.13), which could be attributed to the high C/N ratio (25) of litter. These findings suggested that ecological stoichiometry, such as of enzyme, litter C/N, soil DOC/DOP, and DON/DOP ratios, was a sign of the decoupling of soil microorganisms at the genetic and functional levels to land restoration by plantations. It was found that the stoichiometric ratios of plant biomass served as indicators of microbial functions, whereas the stoichiometric ratios of available nutrients in soil regulated microbial genetic diversity. Therefore, nutrient stoichiometry could serve as a strong predictor of microbial diversity and composition during forest restoration.

Study of Zinc Diffusion Based on S, N-Codoped Honeycomb Carbon Cathodes for High-Performance Zinc-Ion Capacitors.

Capacitors with zinc ions, with excellent stabilities, low cost, and high energy density, are expected to be promising energy storage devices. However, the development of zinc-ion capacitors is quietly restricted by low specific capacity and cycling stability. Herein, to overcome these limitations, honeycomb-structured S, N-codoped carbon (SNPC) is constructed by one-pot calcination of waste corn bracts and thiourea. The honeycomb structure of SNPC is demonstrated to provide abundant active sites that can enhance the extron/ion transport, conductivity for high power export, and ion adsorption capacity in energy storage applications, leading to a higher electrochemical performance achieved. The electrolytes of zinc salt have also been studied. It reveals that the SNPC electrode presents the best electrochemical performance in a 2 M ZnSO4 and 0.5 M ZnCl2 electrolyte mixture because in the electrolyte mixture, Cl- can replace the existing bound water in the solvation structure to form an anion-type water-free solvation structure ZnCl42-. The SNPC-800 electrode with a highly improved surface area (∼909.0 m2 g-1) is proved to be more suitable as the electrode than other materials. Aqueous zinc-ion capacitors (ZICs) have been assembled by the honeycomb-structured SNPC-800 as the cathode, which can achieve a relatively wide working voltage range of 0.1-1.8 V. The SNPC-800 ZICs exhibit a superior specific capacity of 179.1 mA h g-1 at 0.1 A g-1. The energy density of SNPC-800 ZICs reaches an impressive value of 89.6 Wh kg-1 at 53.8 W kg-1, and it sustains 28.3 Wh kg-1 at 1997.6 W kg-1. In addition, there is 99.8% capacity retention in the SNPC-800 ZICs over 5000 cycles. The absorption energy in SPNC is much higher than that in undoped CPC, as confirmed by density functional theory, which reveals that introducing of heteroatoms (S, N) has a comparatively active advantage at increasing the Zn-ion storage capacity. This work proposes a practical strategy for the effective recycling of waste biomass materials into honeycomb carbon electrode materials. Moreover, the honeycomb carbon-based ZICs with excellent electrochemical performance and long-term cycling stability possess great potential to be a superior cathode in practical applications.

Fungal, but not bacterial, diversity and network complexity promote network stability during roadside slope restoration.

To restore degraded roadside ecosystems, conventional methods such as revegetation and soil amendment are frequently employed. However, our understanding of the long-term effects of these restoration approaches on soil microbial diversity and network complexity across different vegetation types remains poor, which contributes to poor restoration outcomes. In this study, we explored the effects of roadside slope restoration on microbial communities across different vegetation types at varying stages of restoration. We found that restoration time had a more pronounced impact on microbial diversity than specific vegetation type. As restoration progressed, microbial network complexity and fungal diversity increased, but bacterial diversity declined, suggesting that keystone taxa may contribute to network complexity. Interestingly, bacterial network complexity increased concomitant with decreasing network modularity and robustness, which may compromise system stability. Distinct vegetation types were associated with restoration-sensitive microbial communities at different restoration stages. Leguminouse and nitrogen-fixing plants, such as Albiziak alkora, Ginkgo biloba, Rhus chinensis, Rhapis excels, and Rubia cordifolia exhibited such associations after five years of restoration. These keystone taxa included Proteobacteria, Actinobacteria, Chloroflexi, Gemmatimonadota, and Myxococcota. We also found that bacterial alpha diversity was significantly correlated with restoration time, soil pH, moisture, available phosphate, nitrate nitrogen, and plant height, while fungal diversity was primarily shaped by restoration time. Together, our findings suggest that soil properties, environmental factors, vegetation type, and dominant species can be manipulated to guide the trajectory of ecological recovery by regulating the abundance of certain microbial taxa.

Shifts of understory vegetation induced by thinning drive the expansion of soil rare fungi.

The gap formation due to forest thinning regulates the understorey microclimate, ground vegetation, and soil biodiversity. However, little is known about abundant and rare taxa's various patterns and assemblage mechanisms under thinning gaps. Thinning gaps with increasing sizes (0, 74, 109, and 196 m2) were established 12 years ago in a 36-year-old spruce plantation in a temperate mountain climate. Soil fungal and bacterial communities were analyzed by MiSeq sequencing and related to soil physicochemical properties and aboveground vegetation. The functional microbial taxa were sorted by FAPROTAX and Fungi Functional Guild database. The bacterial community stabilized under varied thinning intensities and was not different from the control plots, whereas the richness of the rare fungal taxa was at least 1.5-fold higher in the large gaps than in the small ones. Total phosphorus and dissolved organic carbon were the main factors influencing microbial communities in soil under various thinning gaps. The diversity and richness of the entire fungal community and rare fungal taxa increased with the understorey vegetation coverage and shrub biomass after thinning. Gap formation by thinning stimulated the understorey vegetation, the rare saprotroph (Undefined Saprotroph), and mycorrhizal fungi (Ectomycorrhizal-Endophyte-Ericoid Mycorrhizal-Litter Saprotroph-Orchid Mycorrhizal and Bryophyte Parasite-Lichen Parasite-Ectomycorrhizal-Ericoid Mycorrhizal-Undefined Saprotroph), which may accelerate nutrient cycling in forest ecosystems. However, the abundance of Endophyte-Plant Pathogens increased by eight times, which showed the potential risk for the artificial spruce forests. Thus, fungi may be the driving force of forest restoration and nutrient cycling under the increasing intensity of thinning and may induce plant diseases. Therefore, vegetation coverage and microbial functional diversity should be considered to evaluate the sustainability of the artificial forest ecosystem and forest restoration.

Soil properties and root traits are important factors driving rhizosphere soil bacterial and fungal community variations in alpine Rhododendron nitidulum shrub ecosystems along an altitudinal gradient.

Both soil properties and plant root traits are pivotal factors affecting microbial communities. However, there is still limited information about their importance in shaping rhizosphere soil microbial communities, particularly in less-studied alpine shrub ecosystems. To investigate the effects of altitude (3300, 3600, 3900, and 4200 m) on the diversity and composition of rhizosphere soil bacterial and fungal communities, as well as the factors shaping rhizosphere soil microbial communities, we conducted this study in alpine Rhododendron nitidulum shrub ecosystems from the Zheduo mountain of the eastern Tibetan Plateau. Results demonstrated that bacterial community diversity and richness decreased to the lowest value at 3600 m and then increased at higher altitudes compared with 3300 m; whereas fungal richness at 3300 m was much lower than at other altitudes, and was closely related to soil properties and root traits. The composition of rhizosphere soil bacterial and fungal communities at the low altitude (3300 m) was different from that at high altitudes. Permutational multivariate analysis of variance and redundancy analysis indicated that soil properties (soil water content, pH, NO3--N, and available phosphorus) and root traits (surface area, and maximum depth) were the major factors explaining the variations of rhizosphere soil bacterial and fungal communities. Specific bacterial and fungal taxa along altitudes were identified. The bacterial taxa Planctomycetota was dominant at 3300 and 3600 m with low soil nutrient availability and high root surface area, whereas the fungal taxa Mortierellomycota was abundant at 3900 and 4200 m with high soil nutrient availability and low root surface area. These results suggested that different soil microbes can respond differently to altitude. This study provides a novel insight into factors driving rhizosphere soil bacterial and fungal community variations, which could improve our understanding of microbial ecology in alpine R. nitidulum shrub ecosystems along altitude.

Research progress on vegetation restoration of road slopes in China.

China is the largest country in road construction due to rapid economy growth, which results in a large number of exposed slopes. Vegetation restoration of these road slopes has become the dominant method in ecological restoration. We reviewed research progress from three aspects, including key technologies for road slope vegetation restoration, application of vegetation restoration engineering, and factors influencing the vegetation restoration efforts. The slope protection technologies commonly used in road slope vegetation restoration include soil spraying technology, vegetation concrete slope protection technology, thick base material technology, and hydraulic spraying technology. In engineering applications, slope vegetation has the functions such as soil and water conservation, air purification, and landscape restoration. Currently, the most common community configuration is shrub and grass configuration. The main influencing factors of vegetation restoration on road slopes are climate, soil substrate, slope direction, plant species and community configuration used, human factors, and other natural factors (such as hydrology, altitude, microtopography, and wildlife). Future researches should focus on the mechanisms of different factors affecting road slope vegetation restoration, and study ecological substrates and slope protection technologies, plant species and diverse community configuration models suitable for road slope restoration in different climatic regions and site conditions.

[Response of soil Collembola to nitrogen and phosphorus deposition: A review]. / åœŸå£¤è·³è™«å¯¹æ°®ç£·å »åˆ†å“åº”çš„ç ”ç©¶è¿›å±•.

Collembola are among the most abundant and integral group in soil decomposers. They channel C and nutrients from basic food resources to higher trophic levels, and therefore play an irreplaceable role in the underground food web. Collembola community would be altered dramatically by increasing N and P deposition. However, we still know little about how Collembola respond to N and P inputs, which will largely retard our steps to understand the ecological functions of collembolans, material circulation and energy flow of the underground food web, and even C cycling in terrestrial ecosystem. The different classification rules for Collembola functional groups have led to poor comparability of research results in the literature. This review proposed three taxonomic criteria of Collembola and four common research means on trophic relationships, summarized the mechanisms underlying the responses of Collembola to N and P addition alone and coadded. Overall, Collembola generally shows a negative response to N addition namely community density decreases, while a positive response to P addition in most ecosystems. The situation was more complicated under the combined N and P application. In the future, the research of Collembola response to N and P deposition should focus on the scientific taxa of Collembola functional groups, improving the research methods of trophic structure of Collembola, and the mechanism underlying the impacts of N and P interaction on Collembola community.

Phosphorus addition decreases plant lignin but increases microbial necromass contribution to soil organic carbon in a subalpine forest.

Increasing phosphorus (P) inputs induced by anthropogenic activities have increased P availability in soils considerably, with dramatic effects on carbon (C) cycling and storage. However, the underlying mechanisms via which P drives plant and microbial regulation of soil organic C (SOC) formation and stabilization remain unclear, hampering the accurate projection of soil C sequestration under future global change scenarios. Taking the advantage of an 8-year field experiment with increasing P addition levels in a subalpine forest on the eastern Tibetan Plateau, we explored plant C inputs, soil microbial communities, plant and microbial biomarkers, as well as SOC physical and chemical fractions. We found that continuous P addition reduced fine root biomass, but did not affect total SOC content. P addition decreased plant lignin contribution to SOC, primarily from declined vanillyl-type phenols, which was coincided with a reduction in methoxyl/N-alkyl C by 2.1%-5.5%. Despite a decline in lignin decomposition due to suppressed oxidase activity by P addition, the content of lignin-derived compounds decreased because of low C input from fine roots. In contrast, P addition increased microbial (mainly fungal) necromass and its contribution to SOC due to the slower necromass decomposition under reduced N-acquisition enzyme activity. The larger microbial necromass contribution to SOC corresponded with a 9.1%-12.4% increase in carbonyl C abundance. Moreover, P addition had no influence on the slow-cycing mineral-associated organic C pool, and SOC chemical stability indicated by aliphaticity and recalcitrance indices. Overall, P addition in the subalpine forest over 8 years influenced SOC composition through divergent alterations of plant- and microbial-derived C contributions, but did not shape SOC physical and chemical stability. Such findings may aid in accurately forecasting SOC dynamics and their potential feedbacks to climate change with future scenarios of increasing soil P availability in Earth system models.

Evaluating ecological effects of roadside slope restoration techniques: A global meta-analysis.

Given the increase in infrastructure construction, ecological restoration techniques need to be scientifically assessed so that appropriate measures can be taken. However, the specific effects of these techniques are often confounded by multiple ecological stressors, and robust evaluations of their effects are rare. Here, we conducted a global meta-analysis of 68 peer-reviewed publications to quantitatively evaluate the ecological impacts of roadside slope restoration techniques and explored potential mechanisms using linear regression and random-forest models. We found that roadside slope restoration techniques generally enhanced restoration effectiveness, but the recovery rate differed over space and time. Relative to the degraded reference group, the synthetic technique (63.10%) and species selection (62.09%) had more positive impacts on restoring slopes than erosion control (44.82%), seed spraying (43.55%), and substrate amelioration (12.96%). Additionally, we found that vegetation condition, soil quality, and species diversity were negatively correlated with restoration time, implying that recovery might not be stable during early restoration periods. Our findings highlighted the importance of biodiversity for restoration success, but the negative relationship between species diversity, precipitation, and age highlighted the potential risks of losing biodiversity during restoration. Finally, the importance of soil substrate but difficulty in restoring it suggested that restoration actions should stress soil substrate amelioration. Generally, this study provides evidence-based references to support decision making and ensure the effectiveness and sustainability of future slope restoration efforts.

Soil carbon, nitrogen and phosphorus ecological stoichiometry shifts with tree species in subalpine plantations.

Understanding ecological stoichiometric characteristics of soil nutrient elements, such as carbon (C), nitrogen (N) and phosphorus (P) is crucial to guide ecological restoration of plantations in ecologically vulnerable areas, such as alpine and subalpine regions. However, there has been only a few related studies, and thus whether and how different tree species would affect soil C:N:P ecological stoichiometry remains unclear. We compared soil C:N:P ecological stoichiometry of Pinus tabulaeformis, Larix kaempferi and Cercidiphyllum japonicum to primary shrubland in a subalpine region. We observed strong tree-specific and depth-dependent effects on soil C:N:P stoichiometry in subalpine plantations. In general, the C:N, C:P and N:P of topsoil (0-10 cm) are higher than subsoil (>10 cm) layer at 0-30 cm depth profiles. The differences in C:N, N:P and C:P at the topsoil across target tree species were significantly linked to standing litter stock, tree biomass/total aboveground biomass and Margalef's index of plant community, respectively, whereas the observed variations of C:N, N:P and C:P ratio among soil profiles are closely related to differences in soil bulk density, soil moisture, the quantity and quality of aboveground litter inputs as well as underground fine root across plantations examined. Our results highlight that soil nutrients in plantation depend on litter quantity and quality of selected tree species as well as soil physical attributes. Therefore, matching site with trees is crucial to enhance ecological functioning in degraded regions resulting from human activity.

Self-adapted clustering of solute atoms into a confined two-dimensional prismatic platelet with an ellipse-like quasi-unit cell.

This paper reports a new structured prismatic platelet, self-assembled by an ellipse-like quasi-unit cell, precipitated in Mg-In-Yb and Mg-In-Ca ternary alloys and aged isothermally at 200°C using aberration-corrected high-angle annular dark-field scanning transmission electron microscopy combined with density functional theory computations. The ordered stacking of solute atoms along the [0001]α direction based on elliptically shaped self-adapted clustering leads to the generation of the quasi-unit cell. The bonding of these ellipse-like quasi-unit-cell rods by the Mg atomic columns along the 〈〉α directions formed a two-dimensional planar structure, which has three variants with a {}α habit plane and full coherence with the α-Mg matrix. This finding is important for understanding the clustering and stacking behaviors of solute atoms in condensed matter, and is expected to guide the future design of novel high-strength Mg alloys strengthened by such high-density prismatic platelets.

Thinning-induced canopy opening exerted a specific effect on soil nematode community.

Changes in microclimate, soil physicochemical properties, understory vegetation cover, diversity, and composition as well as soil microbial community resulting from silvicultural practices are expected to alter soil food webs. Here, we investigated whether and how contrasting-sized canopy openings affect soil nematode community within a 30 year-aged spruce plantation. The results indicated that the responses of soil nematodes to canopy opening size were dependant on their feeding habit. The abundance of total nematodes and that of free-living nematodes was negatively correlated with soil bulk density, whereas the abundance of omnivore-predators was negatively correlated with soil bulk density and shrubs cover, respectively. The ratio of the sum abundance of predators and omnivores to the plant parasites' abundance, Simpson's dominance index, Pielou's evenness index, and sigma maturity index, maturity index (MI), MI 2-5, basal index, enrichment index, and structure index was sensitive to alteration in canopy opening size. Multivariate analysis indicated that thinning-induced gap size resulted in contrasting nematode assemblages. In conclusion, soil nematodes should be integrated as an indicator to monitor soil multifunctionality change due to thinning.

Differential responses of Picea asperata and Betula albosinensis to nitrogen supply imposed by water availability.

A pot experiment was conducted to investigate the effects of nitrogen (N) addition (0, 20, 40 g N m-2 year-1, N0, N20, N40, respectively) on the growth, and biomass accumulation and allocation of coniferous and deciduous (Picea asperata Mast. and Betula albosinensis Burk.) seedlings under a range of soil moisture limitation (40%, 50%, 60%, 80% and 100% of field capacity, FC). At 100% FC, growth of shade-tolerant P. asperata increased with N supply, while that of shade-intolerant B. albosinensis reached a maximum at N20, declining somewhat thereafter. At 60% FC and lower moisture content, water availability limited the growth of P. asperata seedlings, while N availability became progressively limiting to growth with moisture increasing above 60% FC. The transition from principally water-limited response to N-limited response in B. albosinensis occurred at lower moisture content. For P. asperata, these patterns reflected the responses of roots, consistent with changes in root/shoot biomass. For B. albosinensis the response reflected changes in shoot dimensions and root biomass fraction, the latter decreasing with size and foliar [N]. We are not aware of another study demonstrating such differences in the shape of the growth responses of seedlings of differing potential growth rate, across a range in belowground resource supply. The responses of leaf photosynthesis (as well as photosynthetic water and N-use efficiencies) were consistent with the observed growth response of P. asperata to water and N availability, but not of B. albosinensis, suggesting that leaf area dynamics (not measured) dominated the response of this species. Betula albosinensis, a fast-growing species, has a relative narrow range of soil water and N availability for maximum growth, achieved by preferential allocation to the shoot as resources meet the requirements at moderate N and water supply. In contrast, P. asperata increases shoot biomass progressively with increasing resources up to moderate water supply, preferentially growing more roots when resources are not limiting, suggesting that its capacity to produce shoot biomass may reach a biological limit at moderate levels of resource supply.

Does thinning-induced gap size result in altered soil microbial community in pine plantation in eastern Tibetan Plateau?

Although the effects of gap formation resulting from thinning on microclimate, plant generation and understory plant community have been well documented, the impact of thinning on soil microbial community and related ecological functions of forests particularly in subalpine coniferous region is largely unknown. Here, the effects of thinning on soil microbial abundance and community structure using phospholipid fatty acid (PLFA) in pine plantations were investigated 6 years after thinning. The experimental treatments consisted of two distinct-sized gaps (30 m2 or 80 m2 in size) resulting from thinning, with closed canopy (free of thinning) as control. Soil temperature as well as the biomass of actinomycete and unspecific bacteria was sensitive to gap formation, but all these variables were only responsive to medium gap. Nonmetric multidimensional scaling confirmed that soil microbial community was responsive to gap size. In addition, gap size exerted contrasting effect on bacteria-feeding nematode and fungi-feeding nematodes. In conclusion, thinning-induced gap size would affect soil microbial community through changing soil temperature or the abundance of fungi-feeding nematodes.

[Short-term effects of low intensity thinning simulated by gap on ground microclimate and soil nutrients of pure spruce plantation].

Taking a dense spruce pure plantation as test object and simulating the formation of natural forest gap, this paper studied the effects of low intensity thinning by gap creation on the ground temperature, ground humidity, and nutrient contents in different soil layers of the plantation. In the first year of gap creation, the mean diurnal temperature in the gap across the growth season (May - September) increased, while the mean diurnal humidity decreased. The soil organic matter (SOM) and NH4(+) -N contents in O-horizon (humus layer) increased by 19.62% and 283.85%, and the dissolved organic carbon (DOC) and NO3(-) -N contents decreased by 77.86% and 23.60%, respectively. The SOM, total nitrogen (TN), and NO3(-) -N contents in 0-10 cm soil layer increased by 45.77%, 37.14%, and 75.11%, and the NH4(+) -N, DOC, and total phosphorus (TP) contents decreased by 48.56%, 33.33%, and 13.11%, respectively. All the results suggested that low intensity thinning by gap creation could rapidly improve the ground microclimate of the plantation, and consequently, promote the soil microbial activity and mineralization processes in O-horizon, the release of soil nutrients, and the restoration of soil fertility.

Populus from high altitude has more efficient protective mechanisms under water stress than from low-altitude habitats: a study in greenhouse for cuttings.

Cuttings of Populus przewalskii and P. cathayana, which originated from high and low altitudes in southwest China, were used to examine the effect of water stress on the morphological, physiological and biochemical traits of plants in a greenhouse for one growing season. The dry mass accumulation and allocation, gas exchanges, extent of peroxidation damage, osmotic adjustment and antioxidative defenses, and amounts of pigments were measured to characterize the differences in peroxidation damage and protective mechanisms of two poplar species that contrast in drought tolerance. Under water stress, poplars showed a series of biochemical adjustments and morphological changes as follows: a decrease in leaf relative water content, gas exchanges, plant growth and dry mass accumulation; an increase in relative allocation to roots; an increase in the osmolyte contents (e.g. total amino acids). Additionally, water deficit induced an increase in peroxidation damage [as indicated by an increase in electrolyte leakage, malondialdehyde (MDA), carbonyl (C = O ) and hydrogen peroxide (H(2) O(2) ) content], enhanced activities or contents of antioxidants (e.g. ascorbate peroxidase, guaiacol peroxidase, glutathione redutase and ascorbic acid) and reduced amounts of leaf pigments (e.g. chlorophyll and carotenoid). Furthermore, there were significant differences in the extent of morphological and biochemical changes between the two poplar species. Compared with P. cathayana, P. przewalskii responded to water stress by allocating relatively more to root dry mass, possessing a higher net photosynthesis rate, and having more efficient protective mechanisms, such as more osmolyte accumulation, stronger antioxidant activities and lower chlorophyll/carotenoid ratio. Thus, P. przewalskii suffered less damage as deduced from lower levels of electrolyte leakage, MDA, C=O and H(2) O(2) content. Therefore, P. przewalskii originating from high altitude could possess more efficient protective mechanisms than P. cathayana, which is from low-altitude habitats.

[Growth and reproduction of Rosa multibracteata population in Minjiang River dry valley].

Based on large area field survey and sampling plots investigation, this paper analyzed the distribution, growth and reproduction, and spatial differentiation of native Rosa multibracteata population in the dry valley of Minjiang River. The results showed that this shrub was widely distributed within the area about 170 km long and across the altitude between 1 200 m and 2 600 m from Mianchi Town of Wenchuan County to Zhenjiangguan of Songpan Town. The plant height, base diameter, age, canopy area, sprout number per clump, and hip number each cluster of the shrub were averagely (123.33 +/- 3.13) cm, (12.49 +/- 0.40) mm, (3.34 +/- 0.16) a, (1.30 +/- 0.13) m2, (5.07 +/- 0.39) stem/cluster, and (171.47 +/- 25.90) hip/cluster, respectively. Except the sprout number per cluster, all test parameters showed significantly higher values with increasing altitude and latitude, being most likely related to the improvement of water condition. The increasing fruit output and sprouting number with increasing altitude and latitude was closely related to the better growth, and possibly, to the trade-off of sexual and asexual capability of R. multibracteata across the changing environment. The lack of younger clusters in age structure indicated the instability of the population development, but the fact that the population had bigger ratio of older sprouts and bigger age structure with increasing altitude showed the sustainable development of the population. The stronger capability of R. multibracteata in growth, sprouting, and sexual reproduction in the dry valley of Minjiang River provided reliable guarantee for the sustainable development of the population.

[Effects of ramets adjustment on Quercus liaotungensis growth and seed generation].

This paper studied the effects of different ramets adjustment measures on the growth and seed generation of Quercus liaotungensis shrub in the upper reach of Minjiang River. The results showed that artificially adjusting ramets number largely affected the growth of plant height and sexual reproduction of Q. liaotungensis. The adjustment had little effect on the basal diameter of remained ramets, but obviously affected their height if 2 or 3 ramets per shrub were remained. The number, total length, and total biomass of new branches of adjusted shrub had more increase than those of unadjusted one, especially for the shrub of remaining 2 ramets. In adjusted shrub, the number and total biomass of leaves increased obviously, and the leaf area decreased gradually with increasing number of remained ramets. The shrub with three remained ramets generated most seed, while natural shrub had the biggest weight of single seed.