Short-term Pot Experiment Research Articles

Species selection as a key factor in the afforestation of coastal salt-affected lands: Insights from pot and field experiments

Soil salinization is a significant global issue that leads to land degradation and loss of ecological function. In coastal areas, salinization hampers vegetation growth, and forestation efforts can accelerate the recovery of ecological functions and enhance resilience to extreme climates. However, the salinity tolerance of tree species varies due to complex biological factors, and results between lab/greenhouse and field studies are often inconsistent. Moreover, in salinized areas affected by extreme climatic and human impacts, afforestation with indigenous species may face adaptability challenges. Therefore, it is crucial to select appropriate cross-species salinity tolerance indicators that have been validated in the field to enhance the success of afforestation and reforestation efforts. This study focuses on five native coastal tree species in Taiwan, conducting afforestation experiments on salt-affected soils mixed with construction and demolition waste. It integrates short-term controlled experiments with potted seedlings and long-term field observations to establish growth performance and physiological and biochemical parameters indicative of salinity tolerance. Results showed that Heritiera littoralis Dryand. exhibited the highest salinity tolerance, accumulating significant leaf proline under increased salinity. Conversely, Melia azedarach Linn. had the lowest tolerance, evidenced by complete defoliation and reduced biomass under salt stress. Generally, the field growth performance of these species aligns with the results of short-term pot experiments. Leaf malondialdehyde content from pot experiments proved to be a reliable cross-species salinity tolerance indicator, correlating negatively with field relative height growth and survival rates. Additionally, parameters related to the photosynthetic system or water status, measured using portable devices, also moderately indicated field survival, aiding in identifying potential salt-tolerant tree species. This study underscores the pivotal role of species selection in afforestation success, demonstrating that small-scale, short-term salinity control experiments coupled with appropriate assessment tools can effectively identify species suitable for highly saline and degraded environments. This approach not only increases the success of afforestation but also conserves resources needed for field replanting and maintenance, supporting sustainable development goals.

Varietal Differences in Wet Damage of Broccoli (Brassica oleracea L. var. italica) Under Waterlogging Conditions

Abstract Broccoli is a typical wet-sensitive vegetable. Precipitation levels in Japan have been unusually high recently, so the wet tolerance of broccoli is of great interest to farmers. The purpose of this study is to gather basic information to help with broccoli cultivation in unusually wet conditions by investigating the varying responses of different cultivars to wet conditions. In two-year pot experiments, the early stage of broccoli growth was compared using on cultivars that exhibit unique characteristics in terms of tolerance to wet conditions, and differences in yield were also confirmed during the harvest season in a field experiment. Broccoli plants subjected to three days of waterlogging treatment exhibited wilting, yellowing and reduced biomass. Significant interactions between treatment and cultivar were also detected for biomass, water content, and photosynthetic ability. The ‘Shigemori’ cultivar showed less susceptibility to wet damage compared to the other cultivars. The trend could be observed in the head yield in the field experiment. The unique cultivars shown in this study may be helpful in broccoli cultivation and may be suitable for use as parent material in breeding. Furthermore, a short-term pot experiment can help evaluate broccoli wet tolerance during the early growth.

Enhancing Fertilizer Effect of Bioprocessed Brewers’ Spent Grain by Microbial Consortium Addition

Brewers’ spent grain (BSG) is primarily recycled as livestock feed due to its high fiber content, undegradable protein, and water-soluble vitamins. However, BSG composting represents a possible alternative to organic waste management. Adding a microbial consortium further enhances the agronomical properties of the compost intended for fertilizing applications. Microbial-based fertilizers (plant growth-promoting microorganisms, PGPM) are a means to mitigate the adverse environmental impacts of excessive or improper chemical fertilizer use, enhance the direct or indirect uptake of nutrients by plants, and add value to food waste. In a short-term pot experiment on iceberg lettuce (Lactuca sativa L.), this study assessed the effects of compost and pelletized compost from brewers’ spent grain, both enriched with a microbial consortium. In a randomized block experiment, this study compared four organic BSG fertilizers to chemical fertilizer (NPK) and an unfertilized control treatment. The investigation indicates that BSG compost and BSG pelleted compost, with and without bio-inoculum, in general, are comparable to mineral fertilizer treatment; lettuce fresh weight was higher in pots amended with bioprocessed BSG, associated with more significant growth of soil LAB, fungi, and actinomycetes. The investigation outcomes support composting as an alternative recycling process for producing PGM for agricultural applications.

Loss of soil carbon and nitrogen indicates climate change-induced alterations in a temperate forest ecosystem

Climate warming is expected to influence terrestrial biogeochemical cycles by modifying the quality and quantity of plant litter input to soils. Although a growing number of studies recognize the importance of plant litter input in influencing the loss of soil organic matter (SOM) through a phenomenon called the priming effect (PE), the exact mechanisms behind PE are not well known. Importantly, most PE research is based on short term pot experiments in which fresh organic matter (FOM) input is represented by a single addition of compounds of unnaturally simple chemical composition. Furthermore, only a few studies exist in which the PE was explored in terms of organic C (SOC) and total N content in the soil. Here, we report results of a 3-year long litter manipulation study conducted under natural conditions in a broadleaved Korean pine forest in N-E China. We show that the extra supply (twice the normal input) of aboveground tree litter composing of conifer needles, leaves and small twigs was associated not only with slightly decreased SOC (by 5%) but especially that of soil total N (STN) (by 15%) content in the top soil (0–5 cm depth). In contrast, removal of litter resulted in an increased (ca. 15%) amount of both SOC and STN during the study when compared to control soils receiving natural litter input. Despite the enhanced leaf litter decomposition rate in the treatment receiving extra litter, the changes in SOC and STN were related neither to soil microbial biomass nor to community composition. The amount of N lost (40.0 g m−2) in the soil due to litter addition was ca. three times the amount of N added (12.3 g m−2) via the litter, while the amount of C lost (238 g m−2) was about one third of that added (940 g m−2), suggesting that soil N in our research site is more prone to the PE than soil C. As we did not manipulate belowground FOM input, our results suggest that input of aboveground litter rather than that by roots explained the PE in our study. Results of our long-term study conducted under natural conditions in undisturbed forest soils highlight the large potential of recalcitrant, aboveground litter to affect the PE, which should not go unnoticed when predicting the role of forest soils under conditions (such as climate warming) when these soils act as C sinks.

Effect of Short-Term Phosphorus Supply on Rhizosphere Microbial Community of Tea Plants

Microbes play an important role in rhizosphere phosphorus (P) activation and root P absorption in low P-available soils. However, the responses of the rhizosphere microbial community to P input and its effects on P uptake by tea plants have not been widely reported. In this study, the high-throughput sequencing of the 16S rRNA gene and the ITS2 region was employed to examine the responses of tea rhizosphere microbiomes to different P input rates (low-P, P0: 0 mg·kg−1 P; moderate-P, P1: 87.3 mg·kg−1 P; high-P, P2: 436.5 mg·kg−1 P). The results showed that the P input treatments significantly reduced the soil C: N ratio and C: P ratio compared to the P0 treatment (p < 0.05). Moreover, the P2 treatment significantly increased the soil available P, plant biomass and P content of the tea plant compared to the P0 and P1 treatments (p < 0.05). Both bacterial and fungal communities revealed the highest values of alpha diversity indices in the P1 treatment and the lowest in the P2 treatment. The dominant phyla of the bacterial community were Proteobacteria, Actinobacteria and Acidobacteria, while in the fungal community they were Ascomycota and Mortierellomycota. In addition, P input enriched the relative abundance of Actinobacteria and Proteobacteria but decreased the relative abundance of Acidobacteria. The Mantel correlation analysis showed that the fungal community was influenced by P input, whereas bacterial community was affected by the soil TC and C: N ratio. Furthermore, the P input treatments enhanced the TCA cycle, amino and nucleotide glucose metabolism, starch and sucrose metabolism, and phosphotransferase system expression, which could promote C and N cycling. On the contrary, the P input treatments negatively affected the growth of arbuscular mycorrhizal fungi. The PLS-PM model revealed that the rhizosphere bacterial and fungal communities, respectively, negatively and positively affected the P content by affecting the biomass. Meanwhile, rhizosphere microbial function profiles affected the P content of tea plants directly and positively. In summary, moderate P input favors the rhizosphere microbial diversity and functions in the short-term pot experiment. Therefore, we suggest that moderate P input should be recommended in practical tea production, and a further field test is required.

Co-composting of cattle manure with biochar and elemental sulphur and its effects on manure quality, plant biomass and microbiological characteristics of post-harvest soil.

Improvement of manure by co-composting with other materials is beneficial to the quality of the amended soil. Therefore, the manure was supplied with either biochar, elemental sulphur or both prior to fermentation in 50 L barrels for a period of eight weeks. The manure products were subsequently analyzed and used as fertilizers in a short-term pot experiment with barley fodder (Hordeum vulgare L.). The experiment was carried out under controlled conditions in a growth chamber for 12 weeks. The sulphur-enriched manure showed the lowest manure pH and highest ammonium content. The co-fermentation of biochar and sulphur led to the highest sulphur content and an abundance of ammonium-oxidizing bacteria in manure. The biochar+sulphur-enriched manure led to the highest dry aboveground plant biomass in the amended soil, whose value was 98% higher compared to the unamended control, 38% higher compared to the variant with biochar-enriched manure and 23% higher compared to the manure-amended variant. Amendment of the sulphur-enriched manure types led to the highest enzyme activities and soil respirations (basal, substrate-induced). This innovative approach to improve the quality of organic fertilizers utilizes treated agricultural waste (biochar) and a biotechnological residual product (elementary sulphur from biogas desulphurization) and hence contributes to the circular economy.

Cadmium in Rice Is Affected by Fertilizer-Borne Chloride and Sulfate Anions: Long-Term Field Versus Pot Experiments

In order to investigate the effects of Cl− and SO42− based fertilizers on the accumulation of cadmium (Cd) in rice plants, a long-term experiment, which has been conducted since 1975, and a short-term pot experiment were designed. The results of the long-term experiment showed that the highest total grain Cd was found in the treatment of fertilizers with rich Cl−, which was 72.7% higher compared to conventional fertilization (CF). However, there was no significant difference between the CF and fertilization with rich SO42− treatments. This phenomenon can be explained by the concentrations of the EDTA extractable Cd being significantly increased by 60% under Cl− treatment, while SO42− treatment showed no significant effect. In the short-term trial, compared to CF, Cd concentrations in the roots increased by 1.07 and 0.93 times in the Cl− and SO42− treated soils, respectively, under Cd1.2 exposure. Meanwhile, Cd concentrations in the shoots enhanced by 96% in Cl− treated soil but decreased by 34.6% in SO42− treated soil. It was therefore concluded that fertilizer-borne Cl− significantly increased the Cd concentration in rice grains in the long-term experiment, but fertilizer-borne SO42− had no significant effect on the Cd concentration in rice grains. However, in the pot experiment, SO42− based fertilizers decreased Cd transport to the shoots of a rice plant grown in a Cd contaminated soil. These findings will improve the rational fertilization of Cd contaminated soils and the production of safer rice.

Influence of Organomineral Fertiliser from Sewage Sludge on Soil Microbiome and Physiological Parameters of Maize (Zea mays L.)

The use of a soil fertiliser results in high, good quality yields. The most widely used fertilisers are mineral or organic, but there is increasing attention on organomineral fertilisers produced from sewage sludge. These contain beneficial components which may improve soil fertility and thus plant productivity, but there are some concerns associated with their application due to their composition. Using a short-term pot experiment the effect of such a soil conditioner called FS, produced from sewage sludge after stabilisation with lime, on the qualitative−quantitative composition and activity of soil microorganisms and selected physiological parameters of the maize was analysed. The study was carried out in a completely randomised design, including a control (soil + lime + NPK). The application of the FS had a positive effect on the soil pH, equivalent to the application of lime. Organomineral fertiliser, as a source of organic carbon and macroelements, had a positive effect on the number of soil microorganisms and their activity, and this influence was stable during maize vegetation. FS did not influence the gas exchange activity of maize, the content of assimilation pigments in leaves or and the efficiency of the photosynthetic apparatus determined by chlorophyll “a” fluorescence analysis, but it increased the light absorption efficiency of the PSII photosystem. Differences in biomass yield from organomineral and mineral fertilisation were statistically insignificant.

Biochar and Sulphur Enriched Digestate: Utilization of Agriculture Associated Waste Products for Improved Soil Carbon and Nitrogen Content, Microbial Activity, and Plant Growth

A number of agriculture residues may be used either directly or after suitable treatment as amendments to improve soil quality. Such materials include biochar made of agriculture residues, digestate or elemental sulphur obtained from biogas desulphurisation. The joint use of these materials via pre-incubation may be more advantageous than only mixing prior the application to soil. In this study, digestates were mixed with amendments and incubated for 6 weeks before application to soil in a short-term pot experiment with lettuce (Lactuca sativa). The following treatments were tested: control digestate, digestate + biochar, digestate + elemental sulphur, digestate + biochar + elemental sulphur. The biochar-enriched digestate significantly increased soil microbial biomass, soil C:N, fresh above ground biomass, fresh and dry root biomass. Elemental sulphur-enriched digestate caused highest arylsulfatase and phosphatase, increased urease, microbial biomass in soil and fresh root biomass. Amendment of digestate + biochar + sulphur led to the significantly highest total soil carbon, microbial biomass, β-glucosidase, urease, and increased C:N ratio, arylsulfatase in soil and root biomass. It mitigated the adverse effect of either biochar or elemental sulphur on soil respiration. Properties of digestates were apparently affected by pre-incubation. This approach in digestate fertilizer production may contribute to sustainable farming.

Assessing the potential of biochar aged by humic substances to enhance plant growth and soil biological activity

BackgroundSoil carbon-rich organic amendments (biochar, humic substances) may improve the quality and fertility of arable soil. Their co-application can additively enhance the beneficial effect on soil. Hypothetically, the pre-treatment of biochar, by aging via soaking in a solution of commercially available humic substances, could result in synergism, which may exceed the benefit from simple co-application of both amendments to the soil. Therefore, the aim of this study was to investigate the impact of biochar, humic substances, the combination of both, and the impact of biochar aged by humic substances solution on soil microbial activities and plant growth in a short-term pot experiment with lettuce.ResultsThe aging of biochar decreased the C:N ratio as compared to non-activated biochar. The co-application of biochar and humic substances into the soil resulted in the highest microbial biomass carbon and respiration activity. The majority of enzyme activities (β-glucosidase, arylsulfatase, N-acetyl-β-d-glucosaminidase, phosphatase) were the highest in humic substances-amended soil. The application of humic substances and biochar with humic substances seemed to stimulate microbial growth and activity followed by the competition of microflora for nutrients with plants, whereas the aged biochar behaved differently. The plants treated by aged biochar achieved the highest values of dry aboveground and root biomass of all variants. However, the assumed rapid uptake of nutrients by plants resulted in lower nutrient availability for microflora, and a decline in microbial viability.ConclusionsBased on this study, the positive effect of co-applied humic substances and biochar on soil fertility, quality, and health can be concluded. The usability of biochar aging by humic solution requires further study.Graphic abstract

Assessment of the Short-Term Fertilizer Potential of Mealworm Frass Using a Pot Experiment

The forecasted growth of insect production in the next few years will generate high quantities of frass (insect excreta). Although frass is increasingly considered a potential fertilizer, the dynamics of nutrient supply by frass is still poorly understood. Here, we aimed at gaining insight into the short-term fertilizer value of frass from mealworm (Tenebrio molitor L.) in order to optimize its sustainable use in agroecosystems. Using a short-term pot experiment, we showed that, even though frass has a great potential to be used as a substitute of mineral NPK fertilizer, its N fertilizer potential is mediated by its rate of application. At 10 t ha−1, due to its fast mineralization coupled with improvement in microbial activity (assessed using Biolog EcoPlate), frass was as effective as mineral fertilizer to supply N to plant. By contrast, at 5 t ha−1, the lower frass mineralization induced a reduced N uptake compared to its mineral control. Unlike N, frass was as effective as mineral fertilizer to supply P and K to plants irrespective of its application rate. This was attributed to the presence of P and K in a readily available form in frass. Taken together, our results indicate that mealworm frass supplies very rapidly N, P and K to plants but its effects on N dynamics should be better investigated to warrant its sustainable use as an alternative fertilizer for managing NPK nutrition in cropping systems.

Microbial Changes in the Rhizosphere of Paper Mulberry (<i>Broussonetia papyrifera</i>) Mutant with a High Concentration of Crude Protein

Recently, many studies involving plant-microorganism relationships in the rhizosphere of multitudinous important economic crops revealed a clear signature of the host plant in shaping its rhizosphere microbial composition and structure. The nutrient preference of host plant was suggested to be one important factor determining the structure and assembly of the rhizosphere microbiome, but the proof for this hypothesis is still not enough. In this study, soil microbiomes in the rhizosphere of two Paper mulberry varieties with different nitrogen absorption and utilization efficiency were investigated using a short term pot experiment in controlled greenhouse, and the physicochemical properties were also determined. The results showed that, compared to the control plants, the mutated Paper mulberry variety with high N demand reduced the microbial growth significantly and changed the bacterial and the fungal composition in the rhizosphere soils, and alkaline nitrogen was identified to be the most significant factor affecting soil microbial community. Moreover, the effects of excessive consumption of soil nutrient during Paper mulberry cultivation on the microbiome was revealed, and it could be employed in field water and fertilizer management of Paper mulberry planting. This study further confirmed that the soil nutrient status resulting from the plant nutrient preference drives the development of a plant-specific microbiome.

Humic Acid Mitigates the Negative Effects of High Rates of Biochar Application on Microbial Activity

Objective: Biochar and a commercial humic acid-rich product, Humac (modified leonardite), represent soil amendments with the broad and beneficial effects on various soil properties. Their combination has been scarcely tested so far, although the positive impact of their interaction might be desirable. Materials and Methods: The dehydrogenase activity (DHA), microbial biomass carbon (Cmic), soil respiration (basal and substrate-induced), enzyme activities, total carbon (Ctot), and both shoot and root biomass yield were measured and compared in the short-term pot experiment with the lettuce seedlings. The following treatments were tested: the unamended soil (control), the Humac-amended soil (0.8 g·kg−1), the biochar-amended soil (low biochar 32 g·kg−1, high biochar 80 g·kg−1), and the soil-amended with biochar + Humac. Results: The effect of both amendments on the soil pH was insignificant. The highest average values of Ctot and Cmic were detected in high biochar treatment and the highest average values of basal and substrate-induced respiration (glucose, glucosamine, alanine) were detected in the low biochar treatment. The phosphatase activity and fresh and dry lettuce aboveground biomass were the highest in the low biochar + Humac treatment. Conclusions: Even though the combination of both biochar + Humac decreased the microbial activities in the amended soil (Cmic, DHA, enzymes, substrate-induced respiration) at the low biochar dose, they mitigated the detrimental effect of the high biochar dose on respiration (all the types) and the enzyme (phosphatase, arylsulphatase) activities. In contrast to the previously published research in this issue, the effects could not be attributed to the change of the soil pH.

Evaluation of phytoremediation effects of chicken manure, urea and lemongrass on remediating a lead contaminated soil in Kabwe, Zambia

High levels of lead (Pb) in the soil is a serious issue in the city of Kabwe, Zambia. Phytoremediation is an effective approach to revive the life-supporting functions of the soils. Locally available soil amendments, such as chicken manure, can strengthen phytoremediation. This study aims to find an appropriate combination of a locally available Pb hyperaccumulator, lemongrass (Cymbopogon citratus (DC.) Stapf.), and soil amendments, to minimize the Pb pollution. After a short-term (78 day) pot experiment with lemongrass and three soil amendments (chicken manure, biochar of chicken manure, and urea) on a Pb-contaminated soil in Kabwe, an edible crop, dent corn (Zea mays var. indentata (Sturtev.) L.H.Bailey), was grown for two weeks. Chicken manure combined with lemongrass had the most beneficial impact, reducing the Pb level in dent corn by 19%, compared to the Pb in dent corn grown on the control soil. By growing lemongrass in the Kabwe soil with chicken manure, the exchangeable soil Pb was reduced by 70%. The growth of lemongrass without chicken manure reduced the exchangeable soil Pb by 20%. In conclusion, lemongrass successfully reduced Pb levels, in combination with chicken manure. Soil amendments must be chosen carefully by considering the soil properties and environmental conditions for an optimized Pb reduction.

EFFECT OF BIOCHAR AND FERTILIZERS ON THE DEVELOPMENT OF BARLEY PLANTS AND AGROCHEMICAL INDICES OF SODDY-PODZOLIC SOILS IN A POT EXPERIMENT

The separate and combined effects of biochar and fertilizers in soddy-podzolic sandy and clay loam soils on their basic agrochemical properties, as well as on the growth and development of spring barley (Hordeum vulgare L.) v. Yaromir were studied in a shortterm pot experiment. Wood biochar fractions 3–5 and ≤ 2 mm in 5% dosage (by weight of soil) were used in the experiment. The fertilizers were NPK 16:16:16 and Azotovit, containing living cells and spores of Azotobacter chroococcum bacteria. Studies have shown that the addition of wood biochar to soddy-podzolic sandy soil causes an increase in pH, available potassium and phosphorus, nitrate nitrogen, as well as enhances barley length growth, increases the aboveground biomass and protein content in it. The ≤ 2 mm biochar applied together with NPK pronounced a synergistic effect on almost all parameters. The biochar fraction 3–5 mm together with Azotobacter caused an increase of nitrate nitrogen in the soil and raw protein in barley aboveground biomass. Application of biochar to soddy-podzolic clay loam soil, despite an increase in pH and available potassium and phosphorus, led to a reduction in nitrate nitrogen content, slowed down the growth and development of barley plants, and reduced protein content in them. Apparently, the use of biochar on fine textured soils can create the conditions conducive to denitrification. In the experiment in general, we observed an increase in the content of mineral nitrogen in the treatments with biochar and NPK. Hence, in the presence of an additional source of nitrogen, biochar undergoes intensified mineralization.

Effects of Liquid Organic Fertilizers on Plant Growth and Rhizosphere Soil Characteristics of Chrysanthemum

Organic fertilizers are generally thought to be an effective way to sustain soil fertility and plant growth. To promote the productivity of chrysanthemum, five sources of liquid organic fertilizers (L1–L5), as well as a chemical fertilizer, were applied at an early stage of the growth cycle to investigate their effects on plant growth. In the short-term pot experiment, the liquid organic fertilizers significantly promoted root and aboveground growth by 10.2–77.8% and 10.7–33.3%, respectively, compared with the chemical fertilizer. The order of growth promotion was: L1 (shrimp extracts) > L2 (plant decomposition) > L4 (seaweed extracts)/L5 (fish extracts) > L3 (vermicompost). Morphological and chemical analyses indicated that, compared with other organic fertilizers, the treatment with shrimp extract (L1) produced the greatest increases in root dry weight, total length, surface area, volume, tips, and thick root length, respectively. Furthermore, the shrimp extract treatment significantly increased the nutrient contents and altered the soil’s functional microbial community at the rhizospheric level compared with the chemical fertilizer treatment. Thus, the shrimp extract liquid organic fertilizer could be part of an effective alternative to chemical fertilization during the early stage of chrysanthemum growth.

Influence of soil properties on the performance of the Taxodium hybrid ‘Zhongshanshan 407’ in a short-term pot experiment

ABSTRACTA pot experiment was conducted to investigate the influence of soil properties on the plant growth, nutrient uptake and photosynthetic characteristics of the Taxodium hybrid ‘Zhongshanshan 407ʹ (T. 407). Soils were collected from four different sites across China. These soils showed heterogeneity in pH, nutrients, aggregate distribution and other parameters. The results indicate that the soil of Jiangxi is poorest in terms of soil fertility. T. 407 plants in soils from Tianjin had greater leaf and total biomass, a higher photosynthetic rate (Pn) and more nutrients. Plant total nitrogen (TN), total phosphorus (TP) and total potassium (TK) were positively correlated with soil TN, available phosphorus (AP) and available potassium (AK) (P < 0.01) in all four soils. Path analysis revealed that soil TN and AK were the two major factors affecting Pn. In summary, T. 407 plants exhibited soil-specific characteristics, preferring soils of slightly alkaline pH that were rich in N, P, K and small macroaggregates. This finding is of great relevance for silviculture practices.

Na compound fertilizer stimulates growth and alleviates water deficit in the succulent xerophyte Nitraria tangutorum (Bobr) after breaking seed dormancy

ABSTRACTNitraria tangutorum (Bobr), a typical succulent xerophyte with high level of seed dormancy, is one of the few shrubs found to date that can develop and form fixed dunes in desert regions. Our studies have demonstrated that the strong drought tolerance of the succulent xerophytes was strongly linked to high sodium (Na+) accumulation in the photosynthesizing branches (PB) as well as leaves. The study is to explore a method that can rapidly promote the seed germination of N. tangutorum, and then investigate the positive effects of Na compound fertilizer (NaCF) on the growth and drought tolerance of N. tangutorum and ecological environment by short-term pot experiment in a greenhouse and long-term field and pot experiment in a desert environment. The results indicate that the germination rate of seeds obtained a maximum by 69% when seeds were treated with 150 mg L −1 gibberellic acid (GA3) for 48 h followed by soaking in concentrated sulfuric acid (98% H2SO4) for 55 min, and then germinated (25/5°C) in darkness for 8 d. After breaking seed dormancy, the NaCF significantly stimulated growth of N. tangutorum and, concomitantly, improved its ability to cope with water deficit (30% of field water capacity) by increasing Na+ more than Potassium (K+) accumulation for osmotic adjustment in greenhouse and desert conditions. The contribution (take the pot experiment in the desert, for example) of Na+ to the osmotic potential (compared with control) varied from 13.9% in plants subjected to diammonium phosphate [(NH4)2HPO4] to, surprisingly, 63.9% in plants grown in the presence of NaCF under water deficit. The distribution characteristics of the total Na+ (1620 mg) in the NaCF indicate that 691.2 mg (42.7%) is absorbed by plants, 848.8 mg (52.4%) remained in the pot and 80 mg (4.9%) leached, which accounted for 2.2% of the nursery soil, respectively. The positive effect of NaCF on the drought resistance of N. tangutorum and the ecological environment were also confirmed in the field experiments. These findings suggest that the rapid seed germination technology of N. tangutorum combined with the popularization and application of NaCF can shorten the seed germination period and make the seedling establishment much easier, which may be an effective strategy to restore and reconstruct degraded vegetation in many desert regions.

Sown species richness and realized diversity can influence functioning of plant communities differently.

Biodiversity-ecosystem functioning experiments (BEF) typically manipulate sown species richness and composition of experimental communities to study ecosystem functioning as a response to changes in diversity. If sown species richness is taken as a measure of diversity and aboveground biomass production as a measure of community functioning, then this relationship is usually found to be positive. The sown species richness can be considered the equivalent of a local species pool in natural communities. However, in addition to species richness, realized diversity is also an important community diversity component. Realized diversity is affected by environmental filtering and biotic interactions operating within a community. As both sown species richness and the realized diversity in BEF studies (as well as local species pool vs observed realized richness in natural communities) can differ markedly, so can their effects on the community functioning. We tested this assumption using two data sets: data from a short-term pot experiment and data from the long-term Jena biodiversity plot experiment. We considered three possible predictors of community functioning (aboveground biomass production): sown species richness, realized diversity (defined as inverse of Simpson dominance index), and survivor species richness. Sown species richness affected biomass production positively in all cases. Realized diversity as well as survivor species richness had positive effects on biomass in approximately half of cases. When realized diversity or survivor species richness was tested together with sown species richness, their partial effects were none or negative. Our results suggest that we can expect positive diversity-productivity relationship when the local species pool size is the decisive factor determining realized observed diversity; in other cases, the shape of the diversity-functioning relationship may be quite opposite.

Culture Conditions of a Mycorrhizal Fungus and its Post-Inoculation Microbial Effect

One isolate of mycorrhizal fungi from the roots of wild plant, in this experiment, the growth rate and dry weight of mycelium used as measurement index, PDMA medium is found suitable as basic medium for this strain after 4 kinds of medium are preliminarily screened. Using microbial dilution plate counting cultivation method, the rhizosphere soil microbial quantity were analyzed in a blueberry short-term pot experiment. Results indicate that the number of microbial physiological groups in rhizosphere soil under different varieties of different treatments were significantly differences,and bacteria were dominant,followed by actinomycetes,and fungi were the least.