Legume Tree Research Articles

Inga uruguensis response to lead: effects on growth and nitrogenous compounds

Abstract Lead (Pb) is a heavy metal considered one of the major soil pollutants. Phytoremediation is a sustainable and economically viable biological method for reducing Pb content in the environment. Inga uruguensis is a tree legume species that has characteristics favorable to phytoremediation, such as rapid growth and high biomass production. The objective of this work was an initial evaluation of tolerance and phytoremediation potential of I. uruguensis to Pb. The experiment was carried out in a greenhouse. In addition to the control, soil contamination was carried out with the following Pb doses: 100, 200, 300, 400, and 500 mg.dm³, with 5 repetitions in each treatment, totaling 30 vases. We assessed growth, number and mass of nodules, chlorophyll content, ureids, amino acid, protein and soluble carbohydrates in leaves, roots and nodules, tolerance index, dry matter, and tissues Pb content of I. uruguensis. The data were analyzed by the Tukey test using R and SISVAR software. There was no negative effect of Pb in soil on I. uruguensis growth, the symbiotic relationship with rhizobia was kept, even at high Pb content and the tolerance index was not lower than 0.69. Inga uruguensis has initial tolerance and potential to be used as phytoremediation in soils contaminated by Pb.

Browse from Three Tree Legumes Increases Forage Production for Cattle in a Silvopastoral System in the Southwest Amazon.

Assessing the palatability of forage from locally adapted trees could improve the sustainability of livestock production systems. However, grasses continue to dominate livestock feed across the Amazon. We established a silvopastoral cattle farming system in Peru, comparing three different forage tree species with grass monocultures using a randomised block design. Trees were arranged in alleys of 0.5 × 7.5 m, planted alongside grass, and were directly browsed by cattle. Browse removal was estimated by three methods: destructive sampling, canopy measurements and leaf counts. We found that all three tree species were palatable to cattle. Plots containing trees and grass produced more available forage (mean > 2.2 Mg ha-1) for cattle than the grass monocultures (mean = 1.5 Mg ha-1). Destructive sampling below 1.6 m demonstrated that cattle consumed 99% of the available Erythrina berteroana forage, 75% of the available Inga edulis forage and 80% of the available Leucaena leucocephala forage in 8 days. This research demonstrates methodologies to estimate the intake of locally adapted browse species by cattle and highlights the potential benefits of silvopastoral systems in the Amazon. Planting trees could also benefit animal health and provide ecosystem services such as soil regeneration, enhanced nutrient cycling and carbon capture.

Unexpected high retention of 15 N-labeled nitrogen in a tropical legume forest under long-term nitrogen enrichment.

The responses of forests to nitrogen (N) deposition largely depend on the fates of deposited N within the ecosystem. Nitrogen-fixing legume trees widely occur in terrestrial forests, but the fates of deposited N in legume-dominated forests remain unclear, which limit a global evaluation of N deposition impacts and feedbacks on carbon sequestration. Here, we performed the first ecosystem-scale 15 N labeling experiment in a typical legume-dominated forest as well as in a nearby non-legume forest to determine the fates of N deposition between two different forest types and to explore their underlying mechanisms. The 15 N was sprayed bimonthly for 1year to the forest floor in control and N addition (50kgNha-1 year-1 for 10years) plots in both forests. We unexpectedly found a strong capacity of the legume forest to retain deposited N, with 75 ± 5% labeled N recovered in plants and soils, which was higher than that in the non-legume forest (56±4%). The higher 15 N recovery in legume forest was mainly driven by uptake by the legume trees, in which 15 N recovery was approximately 15% more than that in the nearby non-legume trees. This indicates higher N-demand by the legume than non-legume trees. Mineral soil was the major sink for deposited N, with 39±4% and 34±3% labeled N retained in the legume and non-legume forests, respectively. Moreover, N addition did not significantly change the 15 N recovery patterns of both forests. Overall, these findings indicate that legume-dominated forests act as a strong sink for deposited N regardless of high soil N availability under long-term atmospheric N deposition, which suggest a necessity to incorporate legume-dominated forests into N-cycling models of Earth systems to improve the understanding and prediction of terrestrial N budgets and the global N deposition effects.

Promoting Forage Legume–Pollinator Interactions: Integrating Crop Pollination Management, Native Beekeeping and Silvopastoral Systems in Tropical Latin America

Major declines of insect pollinators are a worldwide concern. Such losses threaten human food supplies and ecosystem functions. Monocultures of pastures used to feed cattle are among the drivers of insect pollinator declines in Tropical Latin America. Plants of the legume family (fabaceae) are mostly pollinated by insects, in particular by bees. The inclusion of legumes in pastures (grass-legume system), as forage banks or the development of silvo-pastoral systems (SPS) with tree legumes, has been widely promoted to improve livestock production and soil fertility, but not to enhance ecosystem services from pollinators. Shortages of seed for the establishment of legumes as forage banks or within pastures or SPS remain a bottleneck for the improvement of ecosystem services brought about by pollinators within these systems and beyond. In this perspective paper, we provide an overview of forage legumes, their interplay with pollinators, and the ecological and socio-economic benefits of pollinator–forage legume interactions, at different scales (farm and landscape level). We further discuss the challenges and opportunities of scaling sustainably intensified cattle production systems that integrate legume forage-seed production with principles of pollinator ecology and native beekeeping. Finally, we provide interested stakeholders, policy-and decision-makers with a perspective on how such agroecosystems may be designed and scaled into multifunctional landscapes.

Assessment of Available Feed Resources in Damot Sore Woreda, Wolaita Zone, Southern Ethiopia

This study was conducted in Damot Sore Woreda, Wolaita Zone, Southern Nation Nationalities and People Regional State with the objective of assessing available feed resources in the area. Eighty households, 40 from Woinadega and 40 from Qolla were selected randomly. A semi-structured questionnaire was prepared and an interview was carried out to collect data. The major feed resources available in the study area included; natural pasture, crop residues, agro-industrial by-products and some improved forages like Elephant grass, pigeon pea, Guatemala, (Desho were described. The major feeding systems practiced in the area were free grazing, rotational grazing, zero grazing/cut and carry systems, tethering and herding together. The major feed production constraints forwarded by the farmers include shortage of grazing land lack of improved forage seed and lack of awareness about conservation of feeds during periods of high availability, less extension work on interventions of feed shortage through improved forage development although some efforts were made by the bureau of agriculture and nongovernmental organization. In general feed conservation in the form of silages and hay, supplementations of tree legumes and treatments of crop residues should be practiced to alleviate feed shortage and boost livestock productivity. Keywords: Availability, Damot Sore; Feed resource, Improved Forages. DOI: 10.7176/RHSS/11-17-01 Publication date: September 30 th 2021

Proportion and digestibility of tree legumes in diets of grazing cattle in a tropical silvopastoral system

In Silvopastoral Systems (SPS) the dynamics and complexity of the combination between grasses and legume trees can significantly impact forage intake and digestibility, affecting livestock performance. This research was composed of two parallel studies. The first one consisted of a field trial assessing three grazing systems: signalgrass (Urochloa decumbens Stapf.) monoculture, and two SPS, one composed of signalgrass + gliricidia [Gliricidia sepium (Jacq.) Kunth.], and another by signalgrass + mimosa (Mimosa caesalpiniifolia Benth), in a randomized complete block design with three replications. Yearling crossbred 5/8 (Holstein/Zebu) steers (175 ± 29 kg initial body weight) were used as experimental animals. Response variables included δ13C in diet and the proportion of C3 species in the feces. The second study was an in situ dry matter digestibility (ISDMD) assay using fistulated male buffalos, and it was evaluated the increasing levels of each legume from the SPS (0, 25%, 50%, 75%, and 100%) in replacement to signalgrass, under different incubation period (24, 48, and 96 h). The range of the carbon isotope (δ13C) found in the cattle's feces (-14.2 to -16.4 ‰), in both signalgrass monoculture pastures and SPS, evidenced the preference of the cattle under SPS for consuming grasses (C4) instead of tree legumes (C3), as both were available. The carbon isotope (δ13C) in plants with C4 metabolism ranges between -9 and -16‰, and in C3 from -22 to -34‰. Increases in the intake of legumes during the dry period might have occurred due to lesser herbage mass and nutritive value of the grass. The ISDMD reached its greater values (>80%) in the inclusion levels of 75 and 100% of gliricidia, at 48- and 96-h incubation (P<0.05). Reductions in the ISDMD coefficients were observed increasing the levels of mimosa in the diet (P<0.01). Adding 100% of mimosa led to decreases in the ISDMD of 54.4% (24 h), 56.8% (48 h), and 49.1% (96 h). The species of legume tree can significantly affect the preference, proportion of C3/C4 species, and the digestibility of the diet of grazing animals in SPS. The grazing cattle in SPS showed a preference for consuming grass instead of legume trees, however, gliricidia was preferred compared to mimosa, especially in periods of lesser grass availability.

Arbuscular mycorrhizal fungi to enhance the growth of tropical endangered species Pterocarpus indicus and Pericopsis mooniana in post gold mine field in Southeast Sulawesi, Indonesia

Abstract. Husna, Tuheteru FD, Arif A. 2021. Arbuscular mycorrhizal fungi to enhance the growth of tropical endangered species Pterocarpus indicus and Pericopsis mooniana in post gold mine field in Southeast Sulawesi, Indonesia. Biodiversitas 22: 3844-3853. Gold mining activities contribute to the national economy, but have a serious impact on forest and environmental degradation and pose a threat to tree species in the tropics. Reforestation of post-gold mining with tropical legume tree species is threatened with extinction. Arbuscular mycorrhizal fungi are effective in conservation of endangered plants and restoration of degraded land. The objective of the study was to evaluate the effect of native AM Fungi inoculation on the growth of Pterocarpus indicus and Pericopsis mooniana in nurseries and post-gold mining fields. P. indicus and P. mooniana seedlings were inoculated with Glomus claroideum Schenk &amp; Smith, Glomus coronatum Giovann., and mixed AMF (G. claroideum, G. coronatum). Uninoculated seedlings were used as control treatment, and they were maintained for 4 months under greenhouse conditions. After 4 months in greenhouse, seedlings were transferred to post-gold mine and planted for 4 months. The percentage of AMF colonization, plant growth, nutrient content and uptake of N, P, K, Fe, Mn were measured after 4 months both in the greenhouse and the field. The percentage of AMF colonization under greenhouse conditions in P. indicus and P. mooniana ranged 5.67-75.3% and 2.2-41.2%. All AMF colonization tended to have higher shoot height, leaf numbers and nodules, plant dry weight and N, P, K content under greenhouse conditions. Shoot height, stem diameter, leaf dry weight, N, P, K, Mn and Fe under field conditions had higher inoculated seedlings than control four months after planting. AMF could be used to conserve endangered tree species in post-gold mining reforestation in the tropics.

Soil Microbial Activity and Biomass in Semiarid Agroforestry Systems Integrating Forage Cactus and Tree Legumes

Vegetation cover affects soil organic matter and activity of soil microorganisms. We investigated the intercropping effect of forage cactus with tree legumes on soil microbial biomass and organic matter in the semi-arid tropic, state of Pernambuco, Brazil. We assessed the following cropping systems: (i) Gliricidia sepium intercropped with cactus cv. IPA-Sertânia; (ii) Leucaena leucocephala intercropped with cactus cv. IPA-Sertânia; and (iii) Cactus cv. IPA-Sertânia in monoculture. Samples were collected during the dry and rainy seasons in the 0- to 0.10- and 0.10- to 0.20-m soil layers at 0, 1.5, 3.0, and 4.5 m in a perpendicular gradient from tree legume rows. The following responses were determined: δ13C and δ15N, C and N, microbial activity and biomass, and metabolic, microbial, and mineralization quotient. δ13C and δ15N varied with the distance from the trees. In the dry season and beginning of the rainy season, the cropping systems showed similar values for C, N, microbial activity, carbon, and nitrogen in the microbial biomass. The presence of tree legumes at the end of the rainy season favored soil microbiota, which showed a reduced loss of C-CO2, with no indication of metabolic stress and greater microbial biomass and microbial quotient in relation to forage cactus in monoculture.

Tree Canopy Management Affects Dynamics of Herbaceous Vegetation and Soil Moisture in Silvopasture Systems Using Arboreal Legumes

Understanding ecological interactions between the arboreal and the herbaceous components is key to get the full benefits from silvopastoral systems. The objective of this 2-yr research was to evaluate productivity and nutritive value of signalgrass (Urochloa decumbens (Stapf.) R. Webster) subjected to shading from the tree legumes Gliricidia (Gliricidia sepium (Jacq.) Steud) or Mimosa (Mimosa caesalpiniifolia Benth.) under different tree canopy management. Trees were planted in double rows and were either unharvested or harvested only one row, leaving the other row unharvested. Response variables for the herbaceous vegetation included canopy height, herbage mass (green leaf blade, green stem, senescent leaves, and senescent stem), herbage accumulation rate, canopy bulk density, and soil moisture. Total herbage mass, green herbage mass, and green leaf mass were affected by treatment × month and harvest management × month interactions. Herbage accumulation rate in Gliricidia was greater (55 kg DM ha−1d−1) than Mimosa (32 kg DM ha−1d−1). Soil moisture was lesser at the Mimosa sites (16.2%) compared with the Gliricidia ones (17.2%), and it was greater between tree rows (21.9%) compared with full sun (11.5%), varying across the season. Harvesting management had a short-term transient effect on herbage responses. Tree canopy management can affect forage quantity and quality; however, these effects are transient and vary with tree spacing. Signalgrass grew faster and had better nutritive value when growing with Gliricidia.

Manure Source and Cropping System Affect Nutrient Uptake by Cactus (Nopalea cochenillifera Salm Dyck)

Forage cactus responds positively to organic fertilization. However, little is known about the mineralization dynamics of the various sources of existing organic fertilizers. Thus, the objective was to evaluate the release of nutrients from different manure types and the nutrient accumulation in forage cactus across different cropping systems. Different manure sources (cattle, goat, sheep, and broiler litter) were evaluated for the following cropping systems: (i) Gliricidia sepium intercropped with cactus cv. IPA-Sertânia; (ii) Leucaena leucocephala intercropped with cactus cv. IPA-Sertânia; and (iii) Cactus cv. IPA-Sertânia in monoculture, in the tropical semiarid region of Brazil. The rate of decomposition and release of N, P, and K from manure was determined by incubating a litterbag, evaluated in different periods (0, 4, 8, 16, 32, 64, 128, and 256 days). Broiler litter released the greatest amount of N and P. Sheep manure released the greatest amounts of K. The greatest accumulations of N, P, and K in cactus biomass occurred when broiler litter was applied. Cactus monoculture accumulated less N over 256 days, indicating that the presence of tree legumes favors the accumulation of N in cactus. Broiler litter promoted the best synchronism between N release and N uptake in different cropping systems.

The Nexus between Fire and Soil Bacterial Diversity in the African Miombo Woodlands of Niassa Special Reserve, Mozambique.

(1) Background: the Miombo woodlands comprise the most important vegetation from southern Africa and are dominated by tree legumes with an ecology highly driven by fires. Here, we report on the characterization of bacterial communities from the rhizosphere of Brachystegia boehmii in different soil types from areas subjected to different regimes. (2) Methods: bacterial communities were identified through Illumina MiSeq sequencing (16S rRNA). Vigna unguiculata was used as a trap to capture nitrogen-fixing bacteria and culture-dependent methods in selective media were used to isolate plant growth promoting bacteria (PGPB). PGP traits were analysed and molecular taxonomy of the purified isolates was performed. (3) Results: Bacterial communities in the Miombo rhizosphere are highly diverse and driven by soil type and fire regime. Independent of the soil or fire regime, the functional diversity was high, and the different consortia maintained the general functions. A diverse pool of diazotrophs was isolated, and included symbiotic (e.g., Mesorhizobium sp., Neorhizobium galegae, Rhizobium sp., and Ensifer adhaerens), and non-symbiotic (e.g., Agrobacterium sp., Burkholderia sp., Cohnella sp., Microvirga sp., Pseudomonas sp., and Stenotrophomonas sp.) bacteria. Several isolates presented cumulative PGP traits. (4) Conclusions: Although the dynamics of bacterial communities from the Miombo rhizosphere is driven by fire, the maintenance of high levels of diversity and functions remain unchanged, constituting a source of promising bacteria in terms of plant-beneficial activities such as mobilization and acquisition of nutrients, mitigation of abiotic stress, and modulation of plant hormone levels.

Arbuscular Mycorrhizal Colonization in Five Tropical Forest Tree Legumes of Chittagong University Campus in Bangladesh

Arbuscular mycorrhizal (AM) colonization in five tropical forest tree legumes (Gliricidia sepium, Dalbergia sissoo, Indigofera tysmanii, Delonix regia and Samanea saman) was investigated in Chittagong University (CU) campus. The results of the present study clearly suggests that, Vesicular AM fungi (VAM) are common in all the studied forest tree species, and that the studied forest tree species differ in their rates of AM formation. The intensity of colonization is maximum (98%) in I. tysmonii followed by D. sissoo (95%), D. regia (63%), S. saman (59%) and G. sepium (52%). Coiled structures of hyphae were recorded in D. regia. Arbuscule formation was recorded in D. sissooand in I. tysmonii. Mycorrhizal spores were found in rhizosphere soils of all the sites. Glomus, Acaulospora, Entrophospora and Gigaspora spores were identified in all the hosts. Forest plants differ in their rates of AM formation. Edhapic conditions like moisture content, soil pH also influence the extent of root colonization.Keyword: Mycorrhizae, Legume, Colonization, Edhapic condition, Rhizosphere, Underground networking.

Grazing patterns affecting browse availability and sustainable management

Ecological biodiversity in Sudan needs a lot of focused work and research to enrich knowledge. Knowledge is of a vital importance for a better use of the vegetation cover to reach sustainable management systems. Browse systems in arid zones seek scientific management since it is strongly bound to activities practiced by people. This study was carried out in an arid area to serve as an example for other similar places. The objectives meant to be studied include the assessment of, first, the browse availability of the most dominant trees, second, to study the ground vegetation cover in terms of density, frequency, forage biomass cover and biodiversity and third, to study the socioeconomic aspects related to browse utilization. Three sites were chosen randomly for the study. Samples of 250m x 250m were selected. Tree species in each sample were identified and tree density was determined by a direct count of the number of trees found. A major founding was the preference of Acacia trees as fodder trees. They provide both fodder for animals and used as a legume tree for soil fertility increase and soil conservation. Trees as legume plants also add nutrients which contribute to soil improvement. The tree density was found reasonable throughout the area whereas the natural regeneration found to be diminishing. Acacia tortilis was the most favorable fodder tree. Water source was the main factor that determines the utilization of browse resources during summertime. Tree density was decreasing due to over grazing, non-tree reseeding together with the drastic climate changes. The study recommended that conservation of plant cover is importantly needed through management and well-planned programs to keep the density of vegetation cover to be within the ecological sustainable balance. A well-designed extension messages were needed to serve maintaining the desired management. Soil conservation programs should be planned in close relation with income generating activities practiced by the poor people in the area. Different bodies that involved in the browse utilization must participate in the management process.

Contrasting genetic signal of recolonization after rainforest fragmentation in African trees with different dispersal abilities

Although today the forest cover is continuous in Central Africa, this may have not always been the case, as the scarce fossil record in this region suggests that arid conditions might have significantly reduced tree density during the ice ages. Our aim was to investigate whether the dry ice age periods left a genetic signature on tree species that can be used to infer the date of the past fragmentation of the rainforest. We sequenced reduced representation libraries of 182 samples representing five widespread legume trees and seven outgroups. Phylogenetic analyses identified an early divergent lineage for all species in West Africa (Upper Guinea) and two clades in Central Africa: Lower Guinea-North and Lower Guinea-South. As the structure separating the Northern and Southern clades-congruent across species-cannot be explained by geographic barriers, we tested other hypotheses with demographic model testing using δαδι. The best estimates indicate that the two clades split between the Upper Pliocene and the Pleistocene, a date compatible with forest fragmentation driven by ice age climatic oscillations. Furthermore, we found remarkably older split dates for the shade-tolerant tree species with nonassisted seed dispersal than for light-demanding species with long-distance wind-dispersed seeds. Different recolonization abilities after recurrent cycles of forest fragmentation seem to explain why species with long-distance dispersal show more recent genetic admixture between the two clades than species with limited seed dispersal. Despite their old history, our results depict the African rainforests as a dynamic biome where tree species have expanded relatively recently after the last glaciation.

Forage tree legumes and sustainable upland farming in Timor Island – Indonesia

Upland farmers in semi-arid region of Timor Island have frequently facing low and uncertain food crops production and chronic forage shortage during long dry season limiting livestock (cattle) production. This study explores forage development, particularly Leucaena and the dynamics of upland farming management among farmer groups in West Timor – Indonesia. The study mostly use forage data of ACIAR and AIAT-ENT collaboration research on forage development, particularly Leucaena conducted in ENT. The data were mostly analysed descriptively. The study showed that adoption of forage legume innovation, particularly Leucaena by upland farmers have solved forage shortage problem during long dry season in semi-arid region of Timor Island, it allowed farmers to do cattle fattening/shortening fattening period and improving crops (maize) production. Drawing on information regarding traditional farming (mixed-cropping) practices for food crops production and traditional local agro-forestry (Mamar) for perennial crops production, the research suggested that incorporated forage tree legume of Leucaena into both traditional farming system can improve/sustain crops and cattle production as well as environment.

Determination of use value and informant consensus factor on ethnobotanic knowledge about wild legumes used by natives of Wayanad district, Kerala

The present work is aimed to document the traditional knowledge about the various usages of leguminous plants (Fabaceae), by tribals of Wayanad district and its nearer places such as Vanimel and Vilangad villages of Kozhikkode district, Kerala. Ethnobotanical surveys/ interviews/ discossions were carried out in few randomly selected tribal hamlets for the data collection. Among these visits the plants used by tribal communities Paniya and Kattunaikka were focused for documentation. This study reports the data of 80 plants from the family Fabaceae. This report also observed that the tribal communities were deeply depending on various wild legumes for making infrastructures, agricultural utilities, making food/ fuel/ timber/ manure and they solve their health issues to a large extent also by using some wild legume species. Among the eighty species, fifty were used in various medicinal preparations and thirty species were used for dietary needs in combination or alone. At the same time major group of plants are unable to demarcate between food and medicine. Use Value analysis shows that the tree legume species Tamarindus indica is relatively more important with 64 use reports (UV 0.98). Analysis of Informant consensus factor reveals that the homogeneity of knowledge is more for the plants with medicinal properties ( F ic 0.97); whereas maximum heterogeneity ( F ic 0.92) was found about agricultural utilities of plants. According to the results of DMR analysis Dalbergia latifolia ranked first, so that this species is getting more exploited, because it is highly preferable for all five categories studied under DMR analysis. Moreover the present documentation of ethnic knowledge about wild legumes is an attempt to serve as indigenous information for future sustainable utilization and conservation.

Bauhinia purpurea L. leaves meal as goat feed

Legume tree forages are generally a source of better feed quality, as a supplement to increase the productivity of ruminant that fed low-quality feed, especially during the dry season. Butterfly leaves (Bauhinia purpurea L.) is a leguminous tree with potential as a fodder source in the dry season because its leaves contain more crude protein than white kabesak Acacia leucophoela Roxb. Legume trees may complement a grass-based diet by providing protein during the dry season. This research aimed to evaluate the effect of Bauhinia purpurea L. leaves meal in complete feed on daily dry matter intake, dry matter digestibility, and average daily body weight gain of goats. The experiment design was a completely randomized block design with 4-four treatments and 4-four groups, using 16 local male goats aged 1–1.5 years and weighed 12.5±0.8 kg. Treatments consisted of four complete feeds containing different levels of Bauhinia purpurea leaves meal (0%, 5%, 10%, and 15%, respectively) in concentrate. Feeds were set up to 9.90±0.5% CP and 69.76±0.5% TDN. Analysis of data utilizes an analysis of variance (ANOVA) and Duncan Multiple Range Test. The results showed that 5– 10% Bauhinia purpurea L. leaves meal in concentrate has no significant effect on daily dry matter intake but significantly decreased dry matter digestibility and increased average daily body weight gain. It can be concluded that Bauhinia purpurea L. leaves meal has the potential to be goat feed.

Seedling Emergence of the Tree Legume Clathrotropis brunnea Amshoff, Endemic from a Colombian Tropical Rainforest

Abstract Seedling emergence is the main propagation method of forest species. Thus, we aimed to evaluate emergence aspects of the tree legume Clathrotropis brunnea Amshoff (sapán or blackheart sapán), a Fabaceae of high economic value endemic to the Colombian rainforest. We characterized the biometry of legumes and seeds and assessed seedling emergence in three experiments: (1) effect of fruit color and substrate, (2) seed conservation in storage, and (3) presoaking and seed position. Our results showed that seeds of green-yellow fruits have greater length and weight and a water content of up to 53%. Seedling emergence did not differ between green-yellow and dark-brown fruits but did differ with substrate type; nearly 80% of seedlings emerged in the sand substrate (S1), but only 62% emerged in the mixed substrate (S3). Fresh sapán seeds are nondormant, showing a recalcitrant behavior in which seedling emergence decreased after storage in all tested conditions. Both seed-sowing positions allowed an emergence of &amp;gt;80% with a small benefit of the hilum downward, regardless of presoaking treatments. However, these differences did not affect seedling height or biomass after emergence. Our results provide basic knowledge on production of tropical seedlings, seeking species conservation, and use in restoration projects.

Fertilization and seasonality influence on the photochemical performance of tree legumes in forest plantation for area recovery in the Amazon.

N-fixing leguminous species can reach atmospheric dinitrogen gas (N2), having an advantage under N-limited degraded environments. These N-fixers are constantly used as facilitative species. Chlorophyll a fluorescence (ChF) acknowledges how different species take up and use light energy during photosynthesis. These techniques assess stress and performance responses to photosynthesis and are used for the selection of species with potential for reforestation. Six Fabaceae species were selected for this study: three nonfixing species (Cenostigma tocantinum, Senna reticulata and Dipteryx odorata) and three N-fixing species (Clitoria fairchildiana, Inga edulis and Acacia spp.). Variations in chlorophyll fluorescence under high vs. low water and nutrient conditions were studied. Multivariate analysis was performed to detect the effects of seasonality and fertilization on dark-adapted ChF two years after the experiment was established. The correlation among ChF variables and growth, photosynthesis and foliar nutrient concentrations was evaluated. Under high water- and nutrient-availability conditions, plants exhibited an enhanced performance index on absorption basis values correlated with electron transport fluxes. Under drought and nutrient-poor conditions, most species exhibit increased energy dissipation as photoprotection. High interspecific variation was found; therefore, species-specific responses should be considered in future ChF studies. Corroborating the ability to colonize high-light environments, N-fixers showed an increased performance index correlated with electron transport and Zn and N foliar concentrations. Negative correlations were found between photosynthesis and trapped fluxes. Diameter growth was positively correlated with electron transport fluxes. Given the different responses among species, ChF is an effective technique to screen for seasonality, fertilization and species effects and should be considered for use during forest restoration. Finally, the addition of fertilization treatments may facilitate tropical forest restoration due to the importance of nutrients in physiological processes. N-fixers showed high photochemical performance and tolerance to abiotic stress in degraded areas and therefore should be included to support ecosystem biomass restoration.

Coordinated adjustments of carbohydrates and growth of tree legumes under different fertilization regimes in degraded areas in Amazonia

Soil fertility management and N-fixing species can support the ecosystem-level restoration of disrupted biogeochemical cycles in tropical degraded environments. However, the effectiveness of N-fixers during tropical forest restoration remains unclear. We hypothesized that tree legumes adjust growth, nonstructural carbohydrate allocation and foliar nutrients under different fertilization regimes. We compared the following six tree legume species: three native nonfixers (Cenostigma, Senna and Dipteryx), two native N-fixers (Clitoria and Inga) and an introduced N-fixer (Acacia). Twenty-four months after the experiment was established, fertilized plants increased growth rates and starch allocation to leaves, whereas unfertilized plants primarily increased their biomass and starch allocation to roots. The greater tolerance to nutrient deficiency of the Acacia than other native tree legumes was due to Acacia’s ability to adjust carbohydrate pools. N-fixers adjusted the shoot-to-root ratio and soluble sugar allocation to leaves, increasing biomass growth. The three N-fixing species were especially suitable for restoration because Acacia had tolerance of nutrient deficiencies, Clitoria and Inga had fast growth and biomass production. Hence, fertilization management and N-fixing species may have a considerable impact on C stocks in different plant compartments. Overall non-structural carbohydrate adjustments influence growth responses of species, especially the ratio between leaf and root tissues. Our findings suggest that this aspect should be considered as a tree species selection criterion for forest restoration programs in the Amazon region.