Small pots limit root and shoot growth in several plant species. In this work, we investigated the effect of pot size (1.7 L and 7 L) on nodulation with Bradyrhizobium japonicum and soybean growth. Small pots restricted the growth of shoots and roots of inoculated and non-inoculated plants and reduced the number of nodules, confirming that pot size interfered with nodule establishment. Plants in small pots had a significant accumulation of calcium (Ca) and boron (B) in the leaves but showed minimal changes in photosynthesis-related parameters. In large pots, inoculated plants showed higher leaf nitrate concentrations and total protein contents, with lower ureide concentrations than plants in small pots. Increased nitrogen use efficiency in plants grown in large pots probably contributed to the higher chlorophyll concentration, leaf area, and pod production when compared to ones in small pots. These findings show that restricting root zone in small pots affects growth and plant nodulation, altering nitrogen metabolism in soybeans. Our results highlight the importance of using large pots in research experiments to mitigate the underestimation of various biochemical responses and better understand the physiological reaction of soybean plants to nodulation. In conclusion, the optimization of pot size in experimental setups is essential for accurately assessing the effects of rhizobial inoculation on soybean performance.

Eucalypts are a diverse group of Myrtaceae native to Australia and adapted to a wide range of edaphoclimatic conditions, including variation in phosphorus (P) soil availability. While Corymbia and Eucalyptus species have evolved in P-poor soils, they still respond to P additions. Nutrient ratios have been used to study nutritional imbalances in plants, as they relate to nutrient homeostasis within cells and ultimately productivity. This study investigated the effects of providing adequate (normal) and high doses of phosphorus (P) on nutrient ratios in leaves and stems of Eucalyptus and Corymbia species. High soil P may happen due to high natural soil concentration and over-fertilization. These species were pre-selected from a 22-eucalypt species screening, based on their responses—either positive, negative, or neutral—to increased dry mass at high soil P compared to normal P. Two species, Corymbia citriodora and C. maculata, which showed increased dry mass under high P levels, exhibited enhanced shoot growth and improvements in parameters related to photosystem efficiency. Except for Zn, which has an antagonistic relationship with P, the concentrations of other nutrients known to exhibit either antagonism or synergism with P were not significantly altered in the leaves and stems. As a result, there were no notable changes in the ratios with high P data compared to those with normal P data. Ratios calculated among K, Ca, Mg, Fe, and Mn data also remained unchanged. However, a principal component analysis, which was performed with all nutrient ratios, effectively separated the normal P and high P treatments and distinguished between species belonging to the genera Corymbia and Eucalyptus. The validity of such nutrient ratios is discussed, and it is suggested that they may not be applicable in studies involving high nutrient doses, which may also be true for other nutrients. Additionally, using ratios under unbalanced field fertilization may lead to an incorrect nutritional interpretation.

Most tropical forests show a low phosphorus (P) concentration in the soil, which limits plant growth and development. Phosphate transporters and regulatory elements, including transcription factors, are involved in the uptake and transport of P from the soil into root cells and other plant organs, and responses to plant P status. To better understand the mechanisms of the root-leaf signalling and remobilisation response to P supply, we applied the split-root technique on two-month-old seedlings of three eucalypt species: Eucalypts grandis, E. globulus, and E. tereticornis. The P treatments were: +P/+P, +P/-P, and -P/-P (+ P and–P indicate P supplementation and P depleted, respectively). P was supplied as 440 µM in the nutrient solution. Eucalypt plants were grown for six weeks and the expression of genes related to P uptake, transport, and utilization in roots and leaves were evaluated by RT-qPCR. The results show that P supply on one side of the root seemed to compensate for the lack of P on the other side in the + P/-P treatment, so the plant did not show a clear P stress response. P remobilization was likely to be the reason for this result. The results revealed significant variations in nutrient concentrations across treatments, with P availability notably impacting the concentrations of B and Cu in leaves. In the root system, variations in P influenced the uptake of other nutrients, such as potassium (K) and magnesium (Mg), in distinct ways among different species. Principal component analysis identified clear patterns of nutrient distribution across treatments and species. Genes related to the Phosphorus Starvation Response were mostly induced when plants were under low P availability, but the expression response was species-dependent. The results demonstrate a complex response of eucalyptus species to uneven P distribution in the root environment, influencing the expression of genes related to P absorption, transport, and metabolism. These findings offer valuable insights into the mechanisms plants employ to adapt to variations in P availability and have important implications for the nutritional management of forest species.

This study is the first to investigate the speciation and spatial distribution patterns of manganese (Mn) accumulated at elevated concentrations in Eucalyptus leaves by X-ray fluorescence (µ-XRF) and absorption near-edge spectroscopy (µ-XANES). Eucalyptus tereticornis is a tree species with great economic value and potential to accumulate and tolerate high Mn despite not being considered a hyperaccumulator. Seedlings grown under glasshouse conditions were irrigated with two Mn treatments: control Mn (9 µM) and high Mn solution (1000 µM). Biomass and total nutrient concentrations were assessed in roots, stems and leaves. Manganese, calcium (Ca) and potassium (K) spatial patterns were imaged by µ-SXRF in different foliar structures, and Mn speciation was conducted in these compartments by µ-XANES. Under high supply, Mn was distributed across the leaf mesophyll suggesting vacuolar sequestration in these cells. High Mn decreased cytosolic Ca by almost 50% in mesophyll cells, but K remained unaltered. Speciation suggests that a majority of the Mn fraction was complexed by organic ligands modeled as Mn-bound malate and citrate, instead of as free aqueous Mn2+ or oxidised forms. These two detoxification mechanisms: effective vacuolar sequestration and organic acid complexation, may be responsible for the impressively high Mn tolerance found in eucalypts.

The coffee sector is estimated to have a retail market value in excess of USD 83 billion, and over 125 million jobs have been created in the global coffee chain. The coffee specialty market has recently increased significantly, generating opportunities to certify coffee beans produced by sustainable practices. This avoids practices potentially harmful to the environment. Agroforestry, organic farming, intercropping, and soil conservation strategies are examples of sustainable alternatives in the production of coffee. In this review, we focus on practices for the sustainable management of coffee plantations that can help farmers fight problems caused by global warming. More specifically, we address soil organic matter and microbiota, the use of Urochloa grass as intercrop in coffee plantations, shading systems (including agroforestry), and organic coffee production. We concluded that from the agronomic viewpoint, we already have production techniques that can replace traditional ones with significant advantages accruing to the quality of coffee orchard ecosystems. Nevertheless, we need scientific research efforts to deal with the existing gaps and the engagement of the whole coffee chain as a means of guaranteeing an adequate profit to those smallholders who adopt and maintain sustainable practice and are capable of bringing several positive changes to the coffee crop, including the use of microbia-based commercial products and new organic sources of nutrients to complement chemical fertilizers and improve coffee quality.

Summary Plant-derived products rely heavily on the availability of phosphorus (P) in the soil. With reserves of P-rocks being limited, there is a growing demand to enhance the efficiency of P utilization by crops. Eucalypts, an important economic crop in many countries, is a source of timber, coal, essence oils, and cellulose. After identifying low P tolerant and susceptible species in a previous study, we explored the various physiological and biochemical responses of these same species to low P availability. The aim was to expand our understanding of how different P-nutrition responses might impact eucalypt wood production and traits related to its quality. Our results indicate that low soil P minimally affects physiological wood parameters in the young trees of Eucalyptus acmenoides, Corymbia maculata, E. grandis, E. globulus, and E. tereticornis. Decreases in cellulose contents and increases in lignin content and syringyl and guaiacyl (S/G) ratios were observed under low P and only in E. acmenoides plants. Wood density remained unaffected in all species. Additionally, bark, stem, and root P concentrations increased under sufficient P conditions in E. globulus, E. grandis, and E. tereticornis. These findings suggest that these plant parts may act as reserve pools of this nutrient.

Plants can modify soil properties over time through interactions with soil microorganisms, creating a legacy that may influence subsequent plant growth. This study investigates how soil vegetation covers affect growth and nutrient uptake and phosphorus (P) and nitrogen (N)use efficiencies in two eucalypt species, and the impact of new plant cultivation on soil microbial traits. Using a greenhouse microcosm experiment, we compared soils from a 20-year eucalypt plantation (Euc) and secondary vegetation (Sec) covers, cultivated for five months with Eucalyptus grandis, E. globulus, or left uncultivated. We measured plant growth, P and N concentrations, root and soil enzyme potential activities, and soil properties. Results showed that E. globulus plants in Euc soil had 23

In regions of low soil phosphorus (P) availability, such as many tropical and subtropical regions, the cultivation of eucalypts is common due to their adaptation to P-constrained soils. As in other trees, the molecular mechanisms underlying the phosphate starvation response (PSR) in eucalypts remain poorly understood. This study aimed to elucidate the molecular responses associated with PSR and assess the efficiency of P acquisition in five eucalypt species: Eucalyptus acmenoides, E. grandis, E. globulus, E. tereticornis, and Corymbia maculata. A greenhouse experiment was carried out in soil/substrate with low resin-extractable P (4.5 mg kg−1, Low P) and sufficient P (10.8 mg kg−1, Sufficient P) availability. After nine months growing in such conditions, various parameters were assessed, such as biomass production, P concentrations, P uptake efficiency (PUpE), and the expression of PSR-related genes. Overall, eucalypt plants exhibited a relatively weak response to low P availability, with slight variations in biomass production, P concentration, and PSR gene expression. C. maculata plants exhibited the highest PUpE under low P, while E. globulus exhibited the lowest. Among PSR-related genes, LPR1/2 in the roots of E. grandis, PDR2 in the roots of C. maculata, and phosphate transporters PHT1;6 and PHT1;8 in the roots of E. globulus, along with PHT1;12 in the roots of E. tereticornis, were induced under low P availability. Elevated PHT1 transcripts in the roots under sufficient P conditions, despite adequate leaf P concentrations, suggest potential interactions with other nutrient availability such as nitrogen, magnesium, and calcium, as well as symbiotic associations. Additionally, the upregulation SQD1 gene involved in membrane lipid remodeling in leaves of E. tereticornis, E. acmenoides, and C. maculata under low P suggests an improved P utilization efficiency. This study reveals the intricate and multifaceted nature of eucalypt responses to soil P availability. Despite the low P concentrations, eucalypt plants maintained foliar concentrations similar to those in the P-sufficient treatment suggesting a complex interplay of factors influencing PSR including nutrient balance.

Understanding how phosphorus (P) deficiency during the reproductive phase of soybean [Glycine max (L.) Merril] affects nitrogen (N) acquisition via biological N fixation (BNF), and seed yield per unit of the accumulated nutrient remains incomplete. Soybean plants were fertigated with a sufficient concentration of P in the nutrient solution (500 µmol L-1 P) until flowering. Subsequently, plants were maintained under this condition or subjected to nutrient deficiencies (20 or 100 µmol L-1 P), resulting in three regimes of P supply during the reproductive phase. At the onset of maximum grain-filling rate and physiological harvest, various parameters were assessed, including nodulation traits, plant nutritional status and biomass production, accumulation, partitioning, and utilization efficiency of P and N. P deficiency after flowering negatively impacted soybean yield and dry mass production, as well as the concentration of P and N in plant organs, their total shoot content, and partitioning to grains. The poor BNF performance was associated with a reduction in the number and dry mass of nodules, triggered by a decrease in plant’s N demand. Nevertheless, low-P stress did not affect seed yield per unit of acquired nutrient, which was related to the fact that the decline in N partitioning to grains was accompanied by a proportional decreasing in their N concentration. The down-regulation of BNF, rather than an impaired N utilization efficiency, contributes to explaining reduced yield of soybean plants facing post-flowering P deficiency. Therefore, the development of precise P fertilization management approaches to maximize BNF and crop yield should prioritize strategies that ensure adequate P supply across the reproductive phase of soybean.

Abstract Phosphorus (P) often limits plant growth and development because its availability in most soils is low, mainly in tropical soils. Various phosphate transporters and regulatory elements, including transcription factors, are involved in the uptake and transport of P from the soil into root cells and to other plant organs. The split-root technique was applied to three eucalypt species to understand better the mechanisms of the root-leaf signaling and remobilization response to P supply. Two-month-old seedlings of Eucalypts grandis, E. globulus, and E. tereticornis were used, with each half of the split root system placed in pots. The P treatments were: +P/+P, +P/-P, and-P/-P (+P = P supplementation and –P = P depleted). P was supplied as 440 μM nutrient solution. Eucalypts plants were grown for six weeks and RT-qPCR evaluated the expression of genes related to P uptake, transport, and utilization in roots and leaves. P supply on one side of the root seemed to compensate for the lack of P on the other side in the +P/-P treatment, so the plant did not show P stress responses, and root-to-root signaling and remobilization in this treatment differed depending on the species. The genes analyzed were mostly induced when plants were under P deprivation, and the expression response was species-dependent. Therefore, this indicates that different mechanisms may be involved in plant response to low P and that signaling control may also be linked to the adaptation of eucalypts species to low soil P.

Extreme temperatures and CO 2 level increments are the two most important effects of global warming and climate change. Because forests have a major impact on the carbon cycle and local climate, it is imperative to understand how tree metabolism copes with temperature and CO 2 alterations. Due to their economic importance, Eucalyptus , Pinus , Populus , and Quercus are the most studied genera regarding wood formation. Primary and secondary metabolism are affected by abiotic stress, and even though trees can adapt to stress, the metabolic consequences imposed by climate change are still rather unknown. In this chapter, we discuss metabolomics studies on the impact of temperature stress and high CO 2 levels and their combined effect on tree metabolism.

Wood formation is a complex process. The cell wall is formed by a number of polymers whose biosynthesis is controlled by several genes. These polymers crosslink to each other to give strength to the cell wall. Additionally, apoptosis takes place for xylem formation. As woody plants are exposed to seasonal variations, meaning that water, light, and temperature change over the year, wood formation is a dynamic process as well. Natural and planted forests are also exposed to nutrient deficiency. While in natural forests nutrients can be recycled, in planted forests a large amount of nutrients is removed with the harvested wood and must be replaced by fertilization. Several works showed that nutrient deficiency can affect wood formation and yield. Despite that, only a limited number of studies have explored the impact of nutrient deficiency on the genetic control of wood formation, and even fewer have examined the alterations in the metabolome and their influence on the formation of the secondary cell wall. In this chapter, we first discuss the literature available on macro and micronutrient deficiencies and wood production. Second, we grouped the works on metabolomics and wood formation, including the few where the interaction between nutrient deficiency and metabolome was the main focus. We concluded that very little is known about the effects that nutrients can have on the wood formation and the particular changes that may occur to alter wood yield and quality.

Tropical soils often present two issues that can hinder plant growth: low phosphorus (P) and high manganese (Mn) availability. Eucalyptus tereticornis is frequently cultivated in such soils. We investigated the effects of Mn in E. tereticornis under contrasting soil P availability and hypothesized that arbuscular mycorrhizal (AM) symbiosis could alleviate Mn toxicity by improving P nutrition and altering the expression of Mn transporter genes. Inoculated (AM) and non-inoculated (NM) seedlings grew for seven months in a soil with low or sufficient P availability, under three Mn doses: control, 75 and 150 mg kg−1 Mn. We assessed growth, AM colonization, nutrient concentrations, and the expression of eight genes related to Mn transport and homeostasis in roots. Mn distribution at one-leaf level was determined by μ-XRF. Low P exacerbated Mn toxicity and hindered plant growth. Mycorrhizal symbiosis did not influence Mn accumulation, but improved growth and Mn tolerance at low P, partly by improving P nutrition. At sufficient P, foliar Mn reached 3500 mg kg−1, and μ-XRF patterns suggest preferential accumulation in the leaf lamina compared to margins or midribs. In NM plants, the vacuolar transporters EtVIT1 and EtMTP8 and the Mn-nicotianamine influx transporter EtYSL6 were the most responsive genes to Mn, while in AM roots most were downregulated. Vacuolar sequestration and transport of complexed Mn are important mechanisms behind Mn tolerance in E. tereticornis. We propose that Mn is transported via the mycorrhizal pathway, explaining why it does not elicit the same molecular response observed in NM roots.

Background and aim We aimed to contribute with the foundation to adopt foliar P fertilization on soybean. Methods Treatments were a combination of contrasting postflowering root P supply versus foliar application of phosphate (Pi) or phosphite (Phi). Results Pi improved grain yield of P-limited plants, while Phi was detrimental because of negative effects on grain weight. Conclusions Thus, cautions should be taken with foliar application of Phi during the generative phase of soybean under low-P stress, as Phi impairs grain filling process.

Global air temperature is rising and resulting in higher frequency and intensity of extreme climatic events. This scenario threatens food security, requiring measures to mitigate the harmful effects of heat stress on agricultural production. Therefore, our study focused on understanding how phosphorus (P) availability during the reproductive period affects seed weight responses of soybean to terminal heat stress. The experiment was carried out in a complete 3 x 2 factorial design, with varying post-flowering P supply (severe deficiency: 20 mu mol P L-1; mild deficiency: 100 mu mol P L-1; sufficiency: 500 mu mol P L-1) and thermal regimes imposed during the seed filling phase (control: 28.0/18.0 degrees C; heat stress: 42.0/28.5 degrees C). Our results revealed that seed weight and yield were unaffected by heat stress in the plants grown under P sufficiency, whereas a detrimental effect of warming on these traits was found in the plants facing post-flowering P deficiency. Sufficient post-flowering P supply alleviated also the harmful effects of heat stress on the integrity of the photosynthetic apparatus, which contributed to improve biomass partitioning to the harvestable organs by extending seed filling duration. Moreover, heat stress disturbed sink metabolism and caused reduction in the concentration of oil and starch solely in the seeds of the plants exposed to P limitation. In conclusion, maintaining adequate post-flowering P supply proves critical in enhancing soybean's tolerance to terminal heat stress by supporting essential processes involved in effective seed filling. Consequently, implementing precise P nutritional management during the reproductive period of soybean might be a promising approach to improve crop yield stability in challenging environmental conditions.

Coffee seedlings are commonly produced on substrate composed of a mixture of soil and cattle manure, supplemented with chemical fertilizers. Alternatives to reduce production costs and produce seedlings of greater quality and health include the use of commercial organic substrates, which require less handling. The use of beneficial microorganisms such as arbuscular mycorrhizal fungi (AMF) can be considered a good alternative for production of more vigorous coffee seedlings. The main goal of this study was to evaluate the effect of the inoculation of AMF isolates on coffee seedlings development in a commercial organic substrate (based on coconut fiber) and conventional substrate (mixture composed of soil and cattle manure compost). Ten AMF were tested: Rhizophagus irregularis, Glomus macrocarpum, Claroideoglomus etunicatum, Rhizophagus clarus, Glomus spp., Gigaspora margarita, Acaulospora morrowiae, Acaulospora scrobiculata, Acaulospora spp., and Dentiscutata heterogamma. Plant growth, shoot P content, mycorrhizal colonization, extraradical mycelium length, phosphatase activity, and photosynthetic pigments were evaluated. The effects of mycorrhization depended on both the inoculated fungal species and the substrate for seedling cultivation. Inoculation of G. margarita, Acaulospora spp., and Glomus spp. in the conventional substrate conferred the best growth plant responses, increasing shoot biomass by 160 to 320%. In the commercial substrate, the most efficient AMF were R. clarus, Glomus spp, A. morrowiae and A. scrobiculata, with up to 149% of shoot biomass increase. The commercial organic substrate and the inoculation of some of the AMF isolates were highly beneficial to coffee seedlings development and can replace the use of the conventional substrate. These results open new opportunities for the use of AMF as an inoculant to improve coffee seedling production in commercial organic substrates.

A significant proportion of the carbon fixed by plants is transported to the roots and exuded to the rhizosphere. Exudates may have important roles in the rhizosphere, such as desorbing labile phosphorus (P) or mobilizing manganese (Mn) and other metal cations. This study evaluated the root exudation profiles of seedlings of 15 eucalypt species in response to a P shortage and if the ability to exude organic compounds was related to P and Mn accumulation in the shoots. The plants were grown on sand and were irrigated with nutrient solutions containing either sufficient P (500 µM) or low P (25 µM). Organic acids (OA), amino acids/polyamines, and phenolics were analyzed in the root exudates by UPLC-MS/MS. Plants with a low P level had low leaf P contents and growth reduction. A P shortage induced the exudation of the three groups of metabolites analyzed at higher levels than sufficient P availability. Despite that, the composition pattern of root exudates was similar among species under low or sufficient P concentrations. Citric and isocitric acids were the major OAs found in the exudates, followed by oxalic, malic, and succinic acids. Among the amino acids/polyamines identified, putrescine was the most abundant in all species, followed by glycine. Cinnamic acid was the predominant phenolic in the root exudates. Our results indicate that P limitation induces a conserved response genetic mechanism in eucalypts. Such results can be further investigated to adapt commercial clones to soils with low P availability.

Cadmium (Cd) can accumulate in vegetables and enter the food chain. The production of vegetables usually uses excessive amounts of fertilizers which bring environmental and health damages. The authors investigate the relationship between fertilization with nitrogen (N), phosphorus (P), and potassium (K) and the accumulation of Cd and nitrate in lettuce of the tropicalized variety "Gloriosa." The experiment is under greenhouse conditions in a 2x2 factorial design, with the addition or not of 10 mg kg(-1) Cd to the soil, and the use of one and three times the recommended rate of N, P, and K for lettuce crop. The higher fertilization rate is related to the increase of Cd in the shoots. Gloriosa lettuce shows high Cd-accumulation capacity, especially in the shoots, evidencing great Cd-translocation. Fresh leaves reach up to 8 mg kg(-1) Cd, higher than permissible limits, but high Cd-tolerance and no visual symptoms of toxicity or reduction in biomass production. In plants grown with three times the recommended rates of N, nitrate concentrations are within the permissible limits for leafy vegetables. To avoid Cd-accumulation, besides monitoring soil Cd, it would be necessary to establish safe rates of fertilization for the cultivation of tropicalized lettuce varieties.

Phosphorus (P) is a vital nutrient for plant growth. P availability is generally low in soils, and plant responses to low P availability need to be better understood. In a previous study, we studied the growth and physiological responses of 24 species to low P availability in the soil and verified of eucalypts, five (Eucalyptus acmenoides, E. grandis, E. globulus, E. tereticornis, and Corymbia maculata) contrasted regarding their efficiency and responsiveness to soil P availability. Here, we obtained the metabolomic and lipidomic profile of leaves, stems, and roots from these species growing under low (4.5 mg dm–3) and sufficient (10.8 mg dm–3) P in the soil. Disregarding the level of P in the soils, P allocation was always higher in the stems. However, when grown in the P-sufficient soil, the stems steadily were the largest compartment of the total plant P. Under low P, the relative contents of primary metabolites, such as amino acids, TCA cycle intermediates, organic acids and carbohydrates, changed differently depending on the species. Additionally, phosphorylated metabolites showed enhanced turnover or reductions. While photosynthetic efficiencies were not related to higher biomass production, A/Ci curves showed that reduced P availability increased the eucalypt species’ Vcmax, Jmax and photosynthetic P-use efficiency. Plants of E. acmenoides increased galactolipids and sulfolipids in leaves more than other eucalypt species, suggesting that lipid remodelling can be a strategy to cope with the P shortage in this species. Our findings offer insights to understand genotypic efficiency among eucalypt species to accommodate primary metabolism under low soil P availability and eventually be used as biochemical markers for breeding programs.

used simple sequence repeat (SSR) markers to assess the genetic diversity of wild and cultivated populations of Arabica coffee from the Boma Plateau in South Sudan, which has been suggested as a centre of origin of Coffea arabica species, in addition to Ethiopia. Comparing these populations with accessions from Ethiopia, Yemen, and global cultivars, they confirmed their hypothesis and showed that the wild population analyzed was genetically distinct from Ethiopian Arabica. Because Arabica coffee is an autogamous species, thus with low genetic variability, South Sudan coffee population can be a rich material to be explored in breeding programs.In another paper, Dullo et al. ( 2021) evaluated the genetic accessions found in the coffee germplasm of CATIE International Coffee Collection (CICC) in Turrialba, Costa Rica, which has genotypes from all over the world, including from missions organized by several organizations to collected wild genetic material in Ethiopia. The methodological approach they created for an in-depth assessment of the collection can be used for other collections and help breeding programs.To