A true facultative carnivore? Effects of replacing ground chicken carcasses with soybean meal on the growth of captive broad-snouted caiman (Caiman latirostris) and its economics implications.

A specific diet for broad-snouted caiman, Caiman latirostris has not been designed despite the value of farm-raised caiman as an aquaculture product. To fill this gap, the objectives of this study were to evaluate the performance dietary replacement of ground chicken carcasses by of soybean meal (SM) as diet complement for C. latirostris. We conducted a 3-month growth trial to determine effects of graded levels of dietary SM on caiman growth as measured by increase in body length, body weight gain, food consumption (FC) and food conversion rate (FCR). Forty-eight hatchling caimans were fed with diets, composed primarily of practical feed ingredients, with 0, 25, or 40% dietary SM. Diets were fed three times per week for 90 days under temperature controlled. Body lengths and body weights were measured at 30-day intervals, and FC samples were taken between the 31-60-day interval. The results of this study indicate that the inclusion of SM in the diet of C. latirostris at levels of 25% increases in body length, body weight gain, FC and improve the FCR indicated that a concentration of 25% dietary SM (as fed) was adequate for growth of caimans under the conditions of this study. Results suggest that SM have a real nutritional contribution in the diet of broad-snouted caiman and can be used as an ingredient of the diet of the crocodilians raised in captivity, reducing production costs for sustainable use and conservation programs of this species.

Effect of intercropping with legumes at different rates on the yield and soil physicochemical properties of Cyperus esculentus L. in arid land.

Intercropping has the potential to enhance yields and nutrient availability in resource-limited agricultural systems. However, the effects on crop yield nutrients and soil properties can vary considerably depending on the specific plant combinations and intercropping ratios used. In this study, the advantages and impacts of intercropping C. esculentus with legumes were investigated by measuring their biomass, nutrient content, and soil properties. The experiment included five intercropping treatments: monoculture of C. esculentus (MC), intercropping of C. esculentus with Medicago sativa L. (alfalfa) at row spacing ratios of 4:4 (4:4CM) and 8:4 (8:4CM), and intercropping of C. esculentus with Glycine max (L.) Merr. (soybean), also at row spacing ratios of 4:4 (4:4CG) and 8:4 (8:4CG). Our results demonstrated that all four intercropping treatments (4:4CM, 4:4CG, 8:4CM, and 8:4CG) significantly increased the biomass of C. esculentus by approximately 41.05%, 41.73%, 16.08%, and 18.43%, respectively, compared with monoculture cultivation alone, among which the 4:4CG treatment was optimum. However, no significant differences were observed in alfalfa or soybean biomass across different intercropping ratios. A notable increase was found in the total nitrogen (TN) and total phosphorus (TP) contents in the leaves, roots, and tubers of C. esculentus under intercropping, along with increased soil organic carbon (SOC), alkaline-hydrolyzed nitrogen (AN), available phosphorus (AP), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and soil water content (SWC), and significantly reduced the soil pH. Among the intercropping treatments, the 4:4CG treatment also exhibited the most favorable soil properties. In particular, compared with MC, the 4:4CG treatment resulted in significant increases of 163.8%, 394.6%, and 716.8% in SOC, AN, and AP contents, respectively. The same treatment also led to significant increases of 48.34%, 46.40%, and 208.65% in MBC, MBN, and SWC, respectively. Overall, the findings suggest that the use of 4:4CG intercropping is an effective approach for sustainable farming management in Xinjiang.

Determination of abundance and symbiotic effectiveness of native rhizobia nodulating soybean and other legumes in Rwanda.

Rhizobia diversity in the rhizosphere is one of the key promoters of biological nitrogen fixation between host legumes and microsymbionts, although related complex interaction may depend on various factors. This research was intended to assess the abundance of indigenous rhizobia isolates under various soil conditions, as well as their effectiveness to nodulate legumes such as soybeans. Factors such as soil properties and legume species influence the volume and symbiotic effectiveness of native rhizobia to nodulate crop legumes. To investigate the abundance of rhizobia isolates, legume crops were uprooted to obtain nodules for most probable number (MPN) determination of rhizobia isolates, and soybean (Glycine max.) was used to verify the presence of suitable and efficient rhizobia strains for nitrogen fixation. Soil samples were obtained from the holes out of which nodules were collected, and the laboratory analysis included pH, Mg, K, available P, organic C, Ca, and N to establish the correlation between the soil status and number of rhizobia isolates' cells. Significant variations (p-value <.05) were observed in the cell counts of Rhizobia isolates from Glycine max, Phaseolus vulgaris, Pisum sativum, and Vigna unguiculata, particularly when compared to Arachis hypogaea isolates under acidic conditions. Notably, Pisum sativum and Vigna unguiculata showed consistent performance across all pH conditions. The number of rhizobia isolates was found to be significantly linked to total N and P deficiencies (p < .05). It was also established that total N was dependent on the number of rhizobia cells and that there is a strong correlation between organic carbon and N content. This study highlights the crucial role of understanding and optimizing conditions for rhizobia nodulation in diverse soil environments, emphasizing its potential impact on enhancing biological nitrogen fixation in legumes.

From salty to thriving: plant growth promoting bacteria as nature's allies in overcoming salinity stress in plants.

Soil salinity is one of the main problems that affects global crop yield. Researchers have attempted to alleviate the effects of salt stress on plant growth using a variety of approaches, including genetic modification of salt-tolerant plants, screening the higher salt-tolerant genotypes, and the inoculation of beneficial plant microbiome, such as plant growth-promoting bacteria (PGPB). PGPB mainly exists in the rhizosphere soil, plant tissues and on the surfaces of leaves or stems, and can promote plant growth and increase plant tolerance to abiotic stress. Many halophytes recruit salt-resistant microorganisms, and therefore endophytic bacteria isolated from halophytes can help enhance plant stress responses. Beneficial plant-microbe interactions are widespread in nature, and microbial communities provide an opportunity to understand these beneficial interactions. In this study, we provide a brief overview of the current state of plant microbiomes and give particular emphasis on its influence factors and discuss various mechanisms used by PGPB in alleviating salt stress for plants. Then, we also describe the relationship between bacterial Type VI secretion system and plant growth promotion.

Effect of Plant Defenses and Plant Nutrients on the Performance of Specialist and Generalist Herbivores of Datura: A Macroevolutionary Study.

Macroevolutionary patterns in the association between plant species and their herbivores result from ecological divergence promoted by, among other factors, plants' defenses and nutritional quality, and herbivore adaptations. Here, we assessed the performance of the herbivores Lema trilineata daturaphila, a trophic specialist on Datura, and Spodoptera frugiperda, a polyphagous pest herbivore, when fed with species of Datura. We used comparative phylogenetics and multivariate methods to examine the effects of Datura species' tropane alkaloids, leaf trichomes, and plant macronutrients on the two herbivores´ performances (amount of food consumed, number of damaged leaves, larval biomass increment, and larval growth efficiency). The results indicate that species of Datura do vary in their general suitability as food host for the two herbivores. Overall, the specialist performs better than the generalist herbivore across Datura species, and performance of both herbivores is associated with suites of plant defenses and nutrient characteristics. Leaf trichomes and major alkaloids of the Datura species are strongly related to herbivores' food consumption and biomass increase. Although hyoscyamine better predicts the key components of the performance of the specialist herbivore, scopolamine better predicts the performance of the generalist; however, only leaf trichomes are implicated in most performance components of the two herbivores. Nutrient quality more widely predicts the performance of the generalist herbivore. The contrasting effects of plant traits and the performances of herbivores could be related to adaptive differences to cope with plant toxins and achieve nutrient balance and evolutionary trade-offs and synergisms between plant traits to deal with a diverse community of herbivores.

Effects of Graphene Oxide on the Growth and Photosynthesis of the Emergent Plant Iris pseudacorus.

The extensive applications of graphene oxide (GO) inevitably lead to entry into the natural aquatic environment. However, information on its toxicity to emergent plants is still lacking. In this study, an emergent plant, Iris pseudacorus, was exposed to GO (1, 20, 80, and 140 mg·L-1) under hydroponic conditions for 15 weeks. Changes in plant growth were assessed by analyzing plant biomass and photosynthetic pigment contents; the photosynthesis response was verified by measuring chlorophyll a fluorescence; and the nutrient levels of the plant were evaluated. Results showed that GO at 20-140 mg·L-1 significantly increased plant dry weight by 37-84% and photosynthetic pigment contents by 26-178%, and 80 mg·L-1 was the optimal concentration. PSII activity, adjustment capacities of electron transport in PSII, the grouping or energetic connectivity between PSII units, light energy conversion efficiency, photosynthesis performance indexes (by 11-51%), and contents of several nutrient elements (N, Fe, and Cu) were increased by 49-69%, 34-84%, and 11-38%, respectively. These findings indicate that GO can enhance plant growth by promoting plant photosynthesis performance and improving plant nutrient levels, and has great application potential in promoting the growth and development of this emergent plant as a phytoremediation agent.

Nitrogen fixation by common beans in crop mixtures is influenced by growth rate of associated species.

BACKGROUND: Legumes can fix atmospheric nitrogen (N) and facilitate N availability to their companion plants in crop mixtures. However, biological nitrogen fixation (BNF) of legumes in intercrops varies largely with the identity of the legume species. The aim of our study was to understand whether BNF and concentration of plant nutrients by common bean is influenced by the identity of the companion plant species in crop mixtures. In this greenhouse pot study, common beans were cultivated with another legume (chickpea) and a cereal (Sorghum). We compared BNF, crop biomass and nutrient assimilation of all plant species grown in monocultures with plants grown in crop mixtures. RESULTS: We found beans to exhibit low levels of BNF, and to potentially compete with other species for available soil N in crop mixtures. The BNF of chickpeas however, was enhanced when grown in mixtures. Furthermore, biomass, phosphorous and potassium values of chickpea and Sorghum plants were higher in monocultures, compared to in mixtures with beans; suggesting competitive effects of beans on these plants. Concentration of calcium, magnesium and zinc in beans was higher when grown with chickpeas than with Sorghum. CONCLUSIONS: It is generally assumed that legumes benefit their companion plant species. Our study highlights the contrary and shows that the specific benefits of cereal-legume mixtures are dependent on the growth rate of the species concerned. We further highlight that the potential of legume-legume mixtures is currently undervalued and may play a strong role in increasing N use efficiency of intercrop-based systems.

Adaptability of Wild-Growing Tulips of Greece: Uncovering Relationships between Soil Properties, Rhizosphere Fungal Morphotypes and Nutrient Content Profiles.

Wild-growing Greek tulips are protected plants but almost nothing is known about their natural nutrient status and rhizosphere fungal morphotypes in the wild, thus no insight is currently available into their growth and adaptation to their natural environment or artificial settings. To this end, several botanical expeditions were conducted with a special collection permit, and 34 tulip and soil samples were collected, representing 13 species from two phytogeographical regions of Greece (North Aegean Islands, Crete Island) and seven regions of mainland Greece. The tulips' content in essential macro- and micro-nutrients, respective physicochemical soil properties, and rhizosphere fungal morphotypes were assessed across samples, and all parameters were subjected to appropriate statistical analysis to determine their interrelationships. The results showed that soil variables played a significant role in shaping tulips' nutrient content, explaining up to 67% of the detected variability as in the case of phosphorus (P) in the above-ground plant tissue. In addition, significant correlations were observed (with an r value of up to 0.65, p < 0.001) between essential nutrients in the tulips, such as calcium (Ca) and boron (B). The principal component analysis (PCA) revealed that between the three spatial units examined, the total variability of tulips' nutrient content produced a clear distinction among sampled species, while the first two PCA axes managed to explain 44.3% of it. This was further confirmed by the analysis of variance (ANOVA) results which showed corresponding significant differences (at p < 0.05) in both the tulips' nutrient content and the studied soil properties as well (mean values of N, P, and K in the North Aegean Islands tulips' nutrient content, up to 53%, 119%, and 54% higher compared to those of the Crete Island, respectively). Our study sheds light on Greek tulips' adaptability and resilience in their original habitats, facilitating at the same time the undertaken efforts regarding their conservation and potential domestication in artificial settings.

Suitable stocking density of fish in paddy field contributes positively to 2-acetyl-1-pyrroline synthesis in grain and improves rice quality.

BACKGROUND: Fragrant rice is increasingly popular with the public owing to its fresh aroma, and 2-acetyl-1-pyrroline (2-AP) is the main characteristic component of the aroma in fragrant rice. Rice-fish co-culture is an environmentally friendly practice in sustainable agriculture. However, the effect of rice-fish co-culture on 2-AP in grains has received little study. A conventional fragrant rice (Meixiangzhan 2) was used, and a related field experiment during three rice growing seasons was conducted to investigate the effects of rice-fish co-culture on 2-AP, as well as the rice quality, yield, plant nutrients, and precursors and enzyme activities of 2-AP biosynthesis in leaves. This study involved three fish stocking density treatments (i.e. 9000 (D1), 15 000 (D2), and 21 000 (D3) fish fries per hectare) and rice monocropping. RESULTS: Rice-fish co-culture increased the 2-AP content in grains by 2.5-49.4% over that of the monocropping, with significant increases in the early and late rice seasons of 2020. Rice-fish co-culture treatments significantly promoted seed-setting rates by 3.39-7.65%, and improved leaf nutrients and rice quality. Notably, the D2 treatment significantly increased leaf total nitrogen (TN), total phosphorus (TP), and total potassium (TK) contents and the head rice rate at maturity stage, while significantly decreased chalkiness degree. There was no significant difference in rice yield. CONCLUSION: Rice-fish co-culture had positive effects on 2-AP synthesis, rice quality, seed-setting rates, and plant nutrient contents. The better stocking density of field fish for rice-fish co-culture in this study was 15 000 fish ha-1 . © 2023 Society of Chemical Industry.

Effects of White and Blue-Red Light on Growth and Metabolism of Basil Grown under Microcosm Conditions.

Indoor farming of basil (Ocimum basilicum L.) under artificial lighting to support year-round produce demand is an area of increasing interest. Literature data indicate that diverse light regimes differently affect downstream metabolic pathways which influence basil growth, development and metabolism. In this study, basil was grown from seedlings to fully developed plants in a microcosm, an innovative device aimed at growing plants indoor as in natural conditions. Specifically, the effects of white (W) and blue-red (BR) light under a photosynthetic photon flux density of 255 µmol m-2 s-1 on plant growth, photochemistry, soluble nutrient concentration and secondary metabolism were investigated. Plants grew taller (41.8 ± 5.0 vs. 28.4 ± 2.5 cm) and produced greater biomass (150.3 ± 24.2/14.7 ± 2.0 g vs. 116.2 ± 28.3/12.3 ± 2.5 g fresh/dry biomass) under W light compared to BR light. The two lighting conditions differently influenced the soluble nutrient concentration and the translocation rate. No photosynthetic stress was observed under the two lighting regimes, but leaves grown under W light displayed higher levels of maximum quantum yield of PSII and electron transport rate. Sharp differences in metabolic patterns under the two lighting regimes were detected with higher concentrations of phenolic compounds under the BR light.

Ozone and Temperature May Hinder Adaptive Capacity of Mediterranean Perennial Grasses to Future Global Change Scenarios.

Climate warming is recognized as a factor that threatens plant species in Mediterranean mountains. Tropospheric ozone (O3) should also be considered as another relevant stress factor for these ecosystems since current levels chronically exceed thresholds for plant protection in these areas. The main aim of the present study was to study the sensitivity of four Mediterranean perennial grasses to O3 and temperature based on plant growth, gas exchange parameters (photosynthesis-A, stomatal conductance-gs, and water use efficiency-WUE), and foliar macro- (N, K, Ca, Mg, P, and S) and micronutrients (B, Cu, Fe, Mn, Mo, and Zn) content. The selected species were grasses inhabiting different Mediterranean habitats from mountain-top to semi-arid grasslands. Plants were exposed to four O3 treatments in Open-Top chambers, ranging from preindustrial to above ambient levels, representing predicted future levels. Chamber-less plots were considered to study the effect of temperature increase. Despite the general tolerance of the grasses to O3 and temperature in terms of biomass growth, WUE and foliar nutrient composition were the most affected parameters. The grass species studied showed some degree of similarity in their response to temperature, more related with phylogeny than to their tolerance to drought. In some species, O3 or temperature stress resulted in low A or WUE, which can potentially hinder plant tolerance to climate change. The relationship between O3 and temperature effects on foliar nutrient composition and plant responses in terms of vegetative growth, A, gs, and WUE constitute a complex web of interactions that merits further study. In conclusion, both O3 and temperature might be modifying the adaptation capacity of Mediterranean perennial grass species to the global change. Air pollution should be considered among the driving favors of biodiversity changes in Mediterranean grassland habitats.

Arbuscular mycorrhizal fungal communities with contrasting life-history traits influence host nutrient acquisition.

Life-history traits differ substantially among arbuscular mycorrhizal (AM) fungal families, potentially affecting hyphal nutrient acquisition efficiency, host nutrition, and thereby plant health and ecosystem function. Despite these implications, AM fungal community life-history strategies and community trait diversity effects on host nutrient acquisition are poorly understood. To address this knowledge gap, we grew sudangrass with AM fungal communities representing contrasting life-history traits and diversity: either (1) five species in the AM family Gigasporaceae, representing competitor traits, (2) five Glomerales species, representing ruderal traits, or (3) a mixed-trait community combining all ten AM fungal species. After 12 weeks, we measured above and belowground plant biomass and aboveground nutrient uptake and concentration. Overall, AM fungal colonization increased host nutrition, biomass, and foliar δ5nitrogen enrichment compared to the uncolonized control. Between the single-trait communities, the Glomeraceae community generally outperformed the Gigasporaceae community in host nutrition and plant growth, increasing plant phosphorus (P) uptake 1.5 times more than the Gigasporaceae community. We saw weak evidence for a synergistic effect of the mixed community, which was only higher for plant P concentration (1.26 times higher) and root colonization (1.26 times higher) compared to the single-trait communities. However, this higher P concentration did not translate to more P uptake or the highest plant biomass for the mixed community. These findings demonstrate that the AM symbiosis is affected by community differences at high taxonomic levels and provide insight into how different AM fungal communities and their associated traits affect host nutrition for fast-growing plant species.

Advances and future research in ecological stoichiometry under saline-alkali stress.

Saline-alkali stress is a serious abiotic factor which negatively impacts agricultural production and the ecological environment. Thus, improving the development of saline-alkali soil and reducing the effects of saline-alkali stress is a key issue for sustainable agricultural development and environmental protection. As such, it is unsurprising that researchers have lately focused on how to improve saline-alkali soil, increase the agricultural yield of saline-alkali land, and promote the adaptive growth of plants in saline-alkali soil. This paper reviews the latest research concerning nutrient content changes in saline-alkali soil, along with the associated changes in key nutrients in plants, to summarize which methods are most effective for improving the plant growth under saline-alkali stress. Finally, the prospects for alleviating saline-alkali stress and improving saline-alkali soil are put forward as a theoretical foundation for the stabilization of plant growth in saline-alkali soil, expansion of arable land area, crop yield improvement, and effective environmental protection.

Soil acidification and the liming potential of biochar.

Soil acidification in managed ecosystems such as agricultural lands principally results from the increased releasing of protons (H+) from the transformation reactions of carbon (C), nitrogen (N) and sulphur (S) containing compounds. The incorporation of liming materials can neutralize the protons released, hence reducing soil acidity and its adverse impacts to the soil environment, food security, and human health. Biochar derived from organic residues is becoming a source of carbon input to soil and provides multifunctional values. Biochar can be alkaline in nature, with the level of alkalinity dependent upon the feedstock and processing conditions. This review covers the fundamental aspects of soil acidification and of the use of biochar to address constraints related to acidic soil. Biochar is increasingly considered as an effective soil amendment for reducing soil acidity owing to its liming potential, thereby enhancing soil fertility and productivity in acid soils. The ameliorant effect on acid soils is mainly because of the dissolution of carbonates, (hydro)-oxides of the ash fraction of biochar and potential use by microorganisms.

Chewing insects, pollinators, and predators on Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) plants fertilized with dehydrated sewage sludge / Insetos mastigadores, polinizadores e predadores em plantas de Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) fertilizada com lodo de esgoto desidratado

Abstract Fertilization with dehydrated sewage sludge can speed up the recovery process of degraded areas due to nutrients concentration, favoring the development of pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) and the emergence of insects. This study aimed the evaluation of chewing, pollinating insects, predators, their ecological indices and relationships on A. auriculiformis plants fertilized with dehydrated sewage sludge. The experimental design was completely randomized with two treatments (with and without dehydrated sewage sludge) and 24 repetitions. The prevalence of chewing insects Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae), and Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), defoliation, and ecological indices of abundance of Coleoptera and Orthoptera were observed on fertilized A. auriculiformis. Acacia auriculiformis plants, with a superior number of branches/tree, revealed greater abundance of Coleoptera and Orthoptera, species richness of pollinating insects, defoliation, numbers of Parasyphraea sp. and T. collaris. The ones with larger leaves/branches displayed greater abundance of species richness of Coleoptera and Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Therefore, the use of A. auriculiformis plants, fertilized with dehydrated sewage sludge, is promising in the recovery of degraded areas due to the ecological indices increase of chewing and pollinators insects and spiders in the analyzed area.

Resumo A fertilização com lodo de esgoto desidratado pode acelerar o processo de recuperação de áreas degradadas devido à concentração de nutrientes, favorecendo o desenvolvimento de plantas pioneiras tais como Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) e de seus insetos. O objetivo deste trabalho foi avaliar os insetos mastigadores, polinizadores e predadores e seus índices e relações ecológicas em plantas de A. auriculiformis fertilizadas com lodo de esgoto desidratado, em área degradada, durante 24 meses. O delineamento foi inteiramente casualizados com dois tratamentos (com e sem adubação com lodo de esgoto desidratado) e 24 repetições (uma repetição = uma planta). O maior número de insetos mastigadores Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae) e Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), de desfolha, e do índice ecológico abundância de Coleoptera e de Orthoptera foram maiores em plantas de A. auriculiformis fertilizadas do que nas não fertilizadas com lodo de esgoto desidratado. Plantas de A. auriculiformis, com maior quantidade de galhos/árvore, apresentaram maiores abundâncias de Coleoptera e Orthoptera, riqueza de espécies de insetos polinizadores, desfolha e números de Parasyphraea sp. e T. collaris, e as com maior folhas/galho os de riqueza de espécies de Coleoptera e Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Por tanto, a utilização de A. auriculiformis, adubada com lodo de esgoto desidratado, é promissora na recuperação de áreas degradadas devido ao aumento dos índices ecológicos de insetos mastigadores, polinizadores e aranhas na área.

Chewing insects, pollinators, and predators on Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) plants fertilized with dehydrated sewage sludge / Insetos mastigadores, polinizadores e predadores em plantas de Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) fertilizada com lodo de esgoto desidratado

Fertilization with dehydrated sewage sludge can speed up the recovery process of degraded areas due to nutrients concentration, favoring the development of pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) and the emergence of insects. This study aimed the evaluation of chewing, pollinating insects, predators, their ecological indices and relationships on A. auriculiformis plants fertilized with dehydrated sewage sludge. The experimental design was completely randomized with two treatments (with and without dehydrated sewage sludge) and 24 repetitions. The prevalence of chewing insects Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae), and Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), defoliation, and ecological indices of abundance of Coleoptera and Orthoptera were observed on fertilized A. auriculiformis. Acacia auriculiformis plants, with a superior number of branches/tree, revealed greater abundance of Coleoptera and Orthoptera, species richness of pollinating insects, defoliation, numbers of Parasyphraea sp. and T. collaris. The ones with larger leaves/branches displayed greater abundance of species richness of Coleoptera and Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Therefore, the use of A. auriculiformis plants, fertilized with dehydrated sewage sludge, is promising in the recovery of degraded areas due to the ecological indices increase of chewing and pollinators insects and spiders in the analyzed area.

A fertilização com lodo de esgoto desidratado pode acelerar o processo de recuperação de áreas degradadas devido à concentração de nutrientes, favorecendo o desenvolvimento de plantas pioneiras tais como Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) e de seus insetos. O objetivo deste trabalho foi avaliar os insetos mastigadores, polinizadores e predadores e seus índices e relações ecológicas em plantas de A. auriculiformis fertilizadas com lodo de esgoto desidratado, em área degradada, durante 24 meses. O delineamento foi inteiramente casualizados com dois tratamentos (com e sem adubação com lodo de esgoto desidratado) e 24 repetições (uma repetição = uma planta). O maior número de insetos mastigadores Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae) e Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), de desfolha, e do índice ecológico abundância de Coleoptera e de Orthoptera foram maiores em plantas de A. auriculiformis fertilizadas do que nas não fertilizadas com lodo de esgoto desidratado. Plantas de A. auriculiformis, com maior quantidade de galhos/árvore, apresentaram maiores abundâncias de Coleoptera e Orthoptera, riqueza de espécies de insetos polinizadores, desfolha e números de Parasyphraea sp. e T. collaris, e as com maior folhas/galho os de riqueza de espécies de Coleoptera e Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Por tanto, a utilização de A. auriculiformis, adubada com lodo de esgoto desidratado, é promissora na recuperação de áreas degradadas devido ao aumento dos índices ecológicos de insetos mastigadores, polinizadores e aranhas na área.

Chewing insects, pollinators, and predators on Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) plants fertilized with dehydrated sewage sludge

Abstract Fertilization with dehydrated sewage sludge can speed up the recovery process of degraded areas due to nutrients concentration, favoring the development of pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) and the emergence of insects. This study aimed the evaluation of chewing, pollinating insects, predators, their ecological indices and relationships on A. auriculiformis plants fertilized with dehydrated sewage sludge. The experimental design was completely randomized with two treatments (with and without dehydrated sewage sludge) and 24 repetitions. The prevalence of chewing insects Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae), and Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), defoliation, and ecological indices of abundance of Coleoptera and Orthoptera were observed on fertilized A. auriculiformis. Acacia auriculiformis plants, with a superior number of branches/tree, revealed greater abundance of Coleoptera and Orthoptera, species richness of pollinating insects, defoliation, numbers of Parasyphraea sp. and T. collaris. The ones with larger leaves/branches displayed greater abundance of species richness of Coleoptera and Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Therefore, the use of A. auriculiformis plants, fertilized with dehydrated sewage sludge, is promising in the recovery of degraded areas due to the ecological indices increase of chewing and pollinators insects and spiders in the analyzed area.

Resumo A fertilização com lodo de esgoto desidratado pode acelerar o processo de recuperação de áreas degradadas devido à concentração de nutrientes, favorecendo o desenvolvimento de plantas pioneiras tais como Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) e de seus insetos. O objetivo deste trabalho foi avaliar os insetos mastigadores, polinizadores e predadores e seus índices e relações ecológicas em plantas de A. auriculiformis fertilizadas com lodo de esgoto desidratado, em área degradada, durante 24 meses. O delineamento foi inteiramente casualizados com dois tratamentos (com e sem adubação com lodo de esgoto desidratado) e 24 repetições (uma repetição = uma planta). O maior número de insetos mastigadores Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae) e Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), de desfolha, e do índice ecológico abundância de Coleoptera e de Orthoptera foram maiores em plantas de A. auriculiformis fertilizadas do que nas não fertilizadas com lodo de esgoto desidratado. Plantas de A. auriculiformis, com maior quantidade de galhos/árvore, apresentaram maiores abundâncias de Coleoptera e Orthoptera, riqueza de espécies de insetos polinizadores, desfolha e números de Parasyphraea sp. e T. collaris, e as com maior folhas/galho os de riqueza de espécies de Coleoptera e Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Por tanto, a utilização de A. auriculiformis, adubada com lodo de esgoto desidratado, é promissora na recuperação de áreas degradadas devido ao aumento dos índices ecológicos de insetos mastigadores, polinizadores e aranhas na área.

Effects of high Ca and Mg stress on plants water use efficiency in a Karst ecosystem.

Background: Karst ecosystems are widely distributed in the world, with one of the largest continuous Karst landforms in Southwest China. Karst regions are characterized by water shortage, high soil calcium (Ca) and magnesium (Mg) content, and soil nutrient leaching, resulting in drought stress and growth limitation of plants. Methods: This study compared nitrogen (N), phosphorus (P), potassium (K), Ca, and Mg of herbaceous and woody plants in a small Karst ecosystem in Southwest China. The indexes of water use efficiency (WUE) were calculated to identify the drought stress of plants in this Karst ecosystem. Meanwhile, the relationship between Ca and Mg accumulation and WUE was evaluated in herbaceous and woody plants. Results: Herbaceous plants showed a higher content of leaf N (13.4 to 40.1 g·kg-1), leaf P (2.2 to 4.8 g·kg-1) and leaf K (14.6 to 35.5 g·kg-1) than woody plants (N: 10.4 g to 22.4 g·kg-1; P: 0.4 to 2.3 g·kg-1; K: 5.7 to 15.5 g·kg-1). Herbaceous plants showed a significantly positive correlation between WUE and K:Ca ratio (R = 0.79), while WUE has a strongly positive correlation with K:Mg ratio in woody plants (R = 0.63). Conclusion: Herbaceous plants suffered from nitrogen (N) limitation, and woody plants were constrained by P or N+P content. Herbaceous plants had higher leaf N, P, and K than woody plants, while Ca and Mg showed no significant differences, probably resulting from the Karst environment of high Ca and Mg contents. Under high Karst Ca and Mg stress, herbaceous and woody plants responded differently to Ca and Mg stress, respectively. WUE of herbaceous plants is more sensitive to Ca stress, while that of woody plants is more sensitive to Mg stress. These findings establish a link between plant nutrients and hydraulic processes in a unique Karst ecosystem, further facilitating studies of the nutrient-water cycling system in the ecosystem.

Water balance affects foliar and soil nutrients differently.

Water balance influences soil development, and consequently plant communities, by driving weathering of soil minerals and leaching of plant nutrients from the soil. Along gradients in water balance, soils exhibit process domains where chemical properties are relatively stable punctuated by pedogenic thresholds where soil chemical properties change rapidly with little additional change in water balance. We ask if plant macronutrient concentrations in leaves also exhibit non-linear trends along water balance gradients, and if so, how these non-linearities relate to those in soils. We analyze foliar nutrient concentrations and foliar N:P ratios from eight species that span a range of growth forms along three water balance gradients (three of the species are found on multiple gradients). The gradients are located on basaltic substrate of different ages and have previously been characterized by studies on soil development. We find that maximum concentrations of foliar macronutrients occur at an intermediate water balance. As with soil nutrients, time mediates the effect of water balance on foliar nutrients, such that plants on older soils attain maximum nutrient concentrations at a lower water balance. On both a young, 20 ky and an old, 4100 ky water balance gradient, foliar nutrients reach peak concentrations at a water balance greater than the threshold for depletion of rock-derived nutrients in surface soils. Our findings suggest that plant acquisition of essential nutrients is imperfectly predicted by overall soil nutrient availability because the regulation of internal nutrient pools by plants makes nutrient pools within leaves partially independent of soil nutrient availability.

Rhodotorula mucilaginosa CAM4 improved selenium uptake in Spinacia oleracea L. and soil enzymatic activities under abiotic stresses.

This study aimed to examine selenium (Se) acquisition by spinach (Spinacia oleracea L.) plants growing under salinity and drought stress through the inoculation of Rhodotorula mucilaginosa strain CAM4. Under abiotic stress conditions, strain CAM4 with Se inoculation increased the shoot length, root length, shoot dry weight and root dry weight by 75.8-93.7%, 47.7-80.9%, 101.9-109.8% and 130.5-270.2%, respectively compared to uninoculated Se-treated plants grown under the same conditions. Under abiotic stresses, the Se-treated CAM4 inoculated plants showed a significant increase in Se concentration in the edible leaves of spinach, which was 227.3-234.5% higher than uninoculated Se-treated control plants. Likewise, strain CAM4 treatment significantly enhanced the plant nutrition of both micro and macro-nutrients. Under normal and abiotic stresses, CAM4 inoculation enhanced soil activities of acid phosphatase, alkaline phosphatase, dehydrogenase, ß-glucosidase and urease in the post harvested soil up to 28-47.5%, 62.6-121.8%, 69-177.1%, 16.2-37.9% and 19.8-41.2%, respectively over corresponding uninoculated soil.