Chlorophyll fluorescence parameters in populations of two legume trees: Stryphnodendron adstringens (Mart.) Coville (Mimosoideae) and Cassia ferruginea (Schrad.) Schrad. ex DC. (Caesalpinoideae)

The aim of this study was to investigate the photosynthetic performance in populations of two legume tree species, Stryphnodendron adstringens (Mimosoideae), typical from Cerrado, and Cassia ferruginea (Caesalpinoideae) from the Atlantic Rain Forest. The photosynthetic traits were assessed by measures of chlorophyll fluorescence in progenies of naturally pollinated plants from three populations of S. adstringens and a population of C. ferruginea. Plants of S. adstringens growing under similar conditions of C. ferruginea plants demanded higher light values for photosynthesis saturation, 600 µmol.m-2.s-1 and 350 µmol.m-2.s-1 respectively, and showed higher intrinsic photosynthetic efficiency of photosystem II, Fv/Fm of 0.814 versus 0.783 in C. ferruginea. The highest values of Fv/Fm observed in S. adstringens can explain the highest electron transport rates (ETR) obtained for this species. No significant differences were found among progenies from different C. ferruginea trees nor among populations of S. adstringens, and only in few cases, variation among progenies within populations were found for S. adstringens plants. The fact that fluorescence parameters distinguished species but not populations or most of progenies may be related to low intraspecific genetic variation of these chlorophyll fluorescence traits or due to lack of expression on genetic differences in plants under no stressful conditions.

Dominance of legume trees alters nutrient relations in mixed species forest restoration plantings within seven years

Failures in reforestation are often attributed to nutrient limitation for tree growth. We compared tree performance and nitrogen and phosphorus relations in adjacent mixed-species plantings of contrasting composition, established for forest restoration on Ultisol soil, originally covered by tropical semi-deciduous Atlantic Forest in Southeast Brazil. Nutrient relations of four tree species occurring in both planting mixtures were compared between a legume-dominated, species-poor direct seeding mixture of early-successional species ("legume mixture"), and a species-diverse, legume-poor mixture of all successional groups ("diverse mixture"). After 7 years, the legume mixture had 6-fold higher abundance of N(2)-fixing trees, 177% higher total tree basal area, 22% lower litter C/N, six-fold higher in situ soil resin-nitrate, and 40% lower in situ soil resin-P, compared to the diverse mixture. In the legume mixture, non-N(2)-fixing legume Schizolobium parahyba (Fabaceae-Caesalpinioideae) had significantly lower proportional N resorption, and both naturally regenerating non-legume trees had significantly higher leaf N concentrations, and higher proportional P resorption, than in the diverse mixture. This demonstrate forms of plastic adjustment in all three non-N(2)-fixing species to diverged nutrient relations between mixtures. By contrast, leaf nutrient relations in N(2)-fixing Enterolobium contortisiliquum (Fabaceae-Mimosoideae) did not respond to planting mixtures. Rapid N accumulation in the legume mixture caused excess soil nitrification over nitrate immobilization and tighter P recycling compared with the diverse mixture. The legume mixture succeeded in accelerating tree growth and canopy closure, but may imply periods of N losses and possibly P limitation. Incorporation of species with efficient nitrate uptake and P mobilization from resistant soil pools offers potential to optimize these tradeoffs.

Nitrogen-tixing and vesicular-arbuscular mycorrhizal symbioses in some tropical legume trees of tribe Mimoseae

Response to mineral fertilization and inoculation with rhizobia and/or arbuscular mycorrhiza fungi (AMF) of the Anadenanthera colubrina, Mimosa bimucronata and Parapiptadenia rigida (Leguminosae-Mimosoideae) native trees from Brazilian riparian forests, were studied in nursery conditions. Each species was submitted to seven treatments, varying nitrogen and phosphorous fertilization and inoculation with rhizobia (r), mycorrhiza (m) or both (rm): NP, P, P + r, P + rm, N, N + m and N + rm. Results showed that AMF inoculations did not enhance the mycorrhizal colonization, and P uptake was not sufficient to sustain good growth of plants. The level of P mineral added affected negatively the AMF colonization in A. colubrina and M. bimucronata, but not in P. rigida. Native fungi infected the three legume hosts. The absence of mineral N limited growth of A. colubrina and P. rigida, but in M. bimucronata the lack of N was corrected by biological nitrogen fixation. N mineral added inhibited the nodulation, although spontaneous nodulation had occurred in A. colubrina and M. bimucronata. Rhizobia inoculation enhanced the number of nodules, nitrogenase activity and leghemoglobin content of these two species. Thus, the extent of rhizobial and mycorrhizal symbiosis in these species under nursery conditions can affect growth and consequently the post-planting success. (C) 2004 Elsevier B.V. All rights reserved.

Does proximity to conspecific adults influence the establishment of ectomycorrhizal trees in rain forest?

Three ectomycorrhizal legume trees, Microberlinia bisulcata, Tetraberlinia bifoliolata and T. moreliana, form discrete groves in the southern part of Korup National Park, in southwest Cameroon and contribute c. 45–70% of stand basal area locally in a matrix of otherwise species-rich arbuscular mycorrhizal forest. A transplant experiment was performed to assess the importance of ectomycorrhizal infection associated with proximity to parents in seedling establishment of the grove-forming species. Nonectomycorrhizal seedlings of the three species were transplanted into plots of two forest types, one of high (HEM, within-grove) and one of very low (LEM, outside the grove) abundance of all three species as adult trees. For two species (T. moreliana and M. bisulcata) there was no difference in survival over 16 months, but for the third (T. bifoliolata) survival was best in HEM forest, and correlated with the basal area of adult trees of ectomycorrhizal species. Only one species (T. moreliana) increased in biomass over the experimental period; the others declined. There was no effect of forest type on overall growth of any species, but the survivors of two (T. moreliana and M. bisulcata) had heavier stems in the HEM forest. Differences in survival and growth of transplants between the three species were in accord with the ecology of the species as inferred from the frequency distributions of adult tree size in the forest. Seedlings became infected with ectomycorrhizas in both forest types; where there was a difference in extent of infection (T. moreliana) this was not related to survival or growth; and where there was a difference in survival (T. bifoliolata) this was not related to extent of infection. These results confirm that mycorrhizal inoculum associated with conspecific adults is neither a prerequisite nor a guarantee of seedling establishment, but indicates that in some circumstances there might be benefits of being close to parents. Further research is required to unravel the complexities of ectomycorrhizal community structure in this spatially and temporally heterogeneous forest, and to clarify the extent to which the various hosts share ectomycorrhizal partners.

Morfologia de plântulas de cinco leguminosas genistóides arbóreas do Brasil (Leguminosae-Papilionoideae)

This work aims to describe, illustrate and compare the seedling morphology of five tree species of the genera Bowdichia, Cyclolobium, Diplotropis, Ormosia, and Poecilanthe, which belong to the genistoid clade (Leguminosae Papilionoideae). Phanero-epigeal-foliaceous seedlings are found in Bowdichia virgilioides Kunth, Cyclolobium brasiliense Benth. has phanero-epigeal-reserve seedlings, while Ormosia arborea (Vell.) Harms, Diplotropis martiusii Benth., and Poecilanthe parviflora Benth. possess crypto-hypogeal-reserve seedlings. Some other relevant seedling morphological characters are discussed and compared with those of previously studied species in these genera.

Understanding the Influences of Spatial Patterns on N Availability Within the Brazilian Amazon Forest

Nitrogen variations at different spatial scales and integrated across functional groups were addressed for lowland tropical forests in the Brazilian Amazon as follows: (1) how does N availability vary across the region over different spatial scales (regional x landscape scale); ( 2) how are these variations in N availability integrated across plant functional groups ( legume 9 non-legume trees). Leaf N, P, and Ca concentrations as well the leaf N isotope ratios (delta(15)N) from a large set of legume and non-legume tree species were measured. Legumes had higher foliar N/Ca ratios than non-legumes, consistent with the high energetic costs in plant growth associated with higher foliar P/Ca ratios found in legumes than in non-legumes. At the regional level, foliar delta(15)N decreased with increasing rainfall. At the landscape level, N availability was higher in the forests on clayey soils on the plateau than in forests on sandier soils. The isotope as well as the non-isotope data relationships here documented, explain to a large extent the variation in delta(15)N signatures across gradients of rainfall and soil. Although at the regional level, the precipitation regime is a major determinant of differences in N availability, at the landscape level, under the same precipitation regime, soil type seems to be a major factor influencing the availability of N in the Brazilian Amazon forest.

Inflorescence and floral development of Dahlstedtia species (Leguminosae: Papilionoideae: Millettieae)

Inflorescence and floral development of two tropical legume trees, Dahlstedtia pinnata and Dahlstedlia pentaphylla, occurring in the Atlantic Forest of south-eastern and southern Brazil, were investigated and compared with other papilionoids. Few studies have been made of floral development in tribe Millettieae, and this paper is intended to fill that gap in our knowledge. Dahlstedtia species have an unusual inflorescence type among legumes, the pseudoraceme, which comprises axillary units of three or more flowers, each with a subtending bract. Each flower exhibits a pair of opposite bractcoles. The order of flower initiation is acropetal; inception of the floral organs is as follows: sepals (5), petals (5), carpel (1) plus outer stamens (5) and finally inner stamens (5). Organ initiation in sepal, petal and inner stamen whorls is unidirectional; the carpel cleft is adaxial. The vexillum originates from a tubular-shaped primordium in mid-development and is larger than other petals at maturity, covering the keels. The filament tube develops later after initiation of inner-stamen primordia. Floral development in Dahlstedtia is almost always similar to other papilionoids, especially species of Phaseoleae and Sophoreae. But one important difference is the precocious ovule initiation (open carpel with ovules) in Dahlstedtia, the third citation of this phenomenon for papilionoids. No suppression, organ loss or anomalies occur in the order of primordia initiation or structure. Infra-generic differences in the first stages of ontogeny are rare; however, different species of Dahlstedtia are distinguished by the differing distribution pattern of secretory cavities in the flower. (C) 2009 Elsevier GmbH. All rights reserved.

Decomposition of ground biomass of secondary forest and yield of annual crops in no tillage

ABSTRACT The objective of this work was to evaluate the dynamics of decomposition process of chopped secondary forest system, previously enriched with legumes Inga velutina Willd. and Stryphnodendron pulcherrimum (Willd.) Hochr. and the contribution of this process to the nutrient input to the cultivation of corn and bean under no-tillage. The experimental design was a randomized block, split plot with four replications. The plots were two species (I. velutina and S. pulcherrimum) and the subplots were seven times of evaluation (0, 7, 28, 63, 189, 252, 294 days after experiment installation). There was no difference (p ≥ 0.05) between the secondary forest systems enriched and no interaction with times for biomass waste, decomposition constant and half-life time. The waste of S. pulcherrimum trees had higher (p < 0.05) C/N ratio than that I. velutina. However, this one was higher (p < 0.05) in lignin content. Nevertheless, the dynamics of residue decomposition was similar. The corn yield was higher (p < 0.05) in cultivation under I.velutina waste. Meanwhile, the beans planted after corn, shows similar (p > 0.05) yield in both areas, regardless of the waste origin.

Inflorescence and floral development of Dahlstedtia species (Leguminosae: Papilionoideae: Millettieae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dinámica del suelo y estoque de carbono después de diez años de la restauración de tierras degradadas usando especies arbóreas del bosque atlántico

Brazil's Atlantic Forest ecosystem has been greatly affected by land use changes, with only 11.26% of its original vegetation cover remaining. Currently, Atlantic Forest restoration is receiving increasing attention because of its potential for carbon sequestration and the important role of soil carbon in the global carbon balance. Soil organic matter is also essential for physical, chemical and biological components of soil fertility and forest sustainability. This study evaluated the potential for soil recovery in contrasting restoration models using indigenous Atlantic Forest tree species ten years after their establishment. The study site is located in Botucatu municipality, São Paulo State-Brazil, in a loamy dystrophic Red-Yellow Argisol site (Typic Hapludult). Four treatments were compared: i) Control (Spontaneous Restoration); ii) Low Diversity (five fast-growing tree species established by direct seeding); iii) High Diversity (mixed plantings of 41 species established with seedlings) and; iv) Native Forest (well conserved neighboring forest fragment). The following soil properties were evaluated: (1) physical-texture, density and porosity; (2) chemical-C, N, P, S, K, Ca, Mg, Al and pH; (3) biological-microbial biomass. Litter nutrient concentrations (P, S, K, Ca and Mg) and C and N litter stocks were determined. Within ten years the litter C and N stocks of the Low Diversity treatment area were higher than Control and similar to those in both the High Diversity treatment and the Native Forest. Soil C stocks increased through time for both models and in the Control plots, but remained highest in the Native Forest. The methods of restoration were shown to have different effects on soil dynamics, mainly on chemical properties. These results show that, at least in the short-term, changes in soil properties are more rapid in a less complex system like the Low Diversity model than in the a High Species Diversity model. For both mixed plantation systems, carbon soil cycling can be reestablished, resulting in increases in carbon stocks in both soil and litter.

Caracterização morfológica, bioquímica e molecular de rizóbios recomendados para inoculação de leguminosas arbóreas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tree size and fecundity influence ballistic seed dispersal of two dominant mast-fruiting species in a tropical rain forest

Seed production, seed dispersal, and seedling recruitment are integral to forest dynamics, especially in masting species. Often these are studied separately, yet scarcely ever for species with ballistic dispersal even though this mode of dispersal is common in legume trees of tropical African rain forests. Here, we studied two dominant main-canopy tree species, Microberlinia bisulcata and Tetraberlinia bifoliolata (Caesalpinioideae), in 25 ha of primary rain forest at Korup, Cameroon, during two successive masting events (2007/2010). In the vicinity of c. 100 and 130 trees of each species, 476/580 traps caught dispersed seeds and beneath their crowns c. 57,000 pod valves per species were inspected to estimate tree-level fecundity. Seed production of trees increased non-linearly and asymptotically with increasing stem diameters. It was unequal within the two species’ populations, and differed strongly between years to foster both spatial and temporal patchiness in seed rain. The M. bisulcata trees could begin seeding at 42–44 cm diameter: at a much larger size than could T. bifoliolata (25 cm). Nevertheless, per capita life-time reproductive capacity was c. five times greater in M. bisulcata than T. bifoliolata owing to former’s larger adult stature, lower mortality rate (despite a shorter life-time) and smaller seed mass. The two species displayed strong differences in their dispersal capabilities. Inverse modelling (IM) revealed that dispersal of M. bisulcata was best described by a lognormal kernel. Most seeds landed at 10–15 m from stems, with 1% of them going beyond 80 m (<100 m). The direct estimates of fecundity significantly improved the models fitted. The lognormal also described well the seedling recruitment distribution of this species in 121 ground plots. By contrast, the lower intensity of masting and more limited dispersal of the heavier-seeded T. bifoliolata prevented reliable IM. For this species, seed density as function of distance to traps suggested a maximum dispersal distance of 40–50 m, and a correspondingly more aggregated seedling recruitment pattern ensued than for M. bisulcata. From this integrated field study, we conclude that the reproductive traits of M. bisulcata give it a considerable advantage over T. bifoliolata by better dispersing more seeds per capita to reach more suitable establishment sites, and combined with other key traits they explain its local dominance in the forest. Understanding the linkages between size at onset of maturity, individual fecundity, and dispersal capability can better inform the life-history strategies, and hence management, of co-occurring tree species in tropical forests.

Soil mineral N dynamics beneath mixtures of leaves from legume and fruit trees in Central Amazonian multi-strata agroforests

Long term applications of leguminous green mulch could increase mineralizable nitrogen (N) beneath cupuaçu trees produced on the infertile acidic Ultisols and Oxisols of the Amazon Basin. However, low quality standing cupuaçu litter could interfere with green mulch N release and soil N mineralization. This study compared mineral N, total N, and microbial biomass N beneath cupuaçu trees grown in two different agroforestry systems, north of Manaus, Brazil, following seven years of different green mulch application rates. To test for net interactions between green mulch and cupuaçu litter, dried gliricidia and inga leaves were mixed with senescent cupuaçu leaves, surface applied to an Oxisol soil, and incubated in a greenhouse for 162 days. Leaf decomposition, N release and soil N mineralization were periodically measured in the mixed species litter treatments and compared to single species applications. The effect of legume biomass and cupuaçu litter on soil mineral N was additive implying that recommendations for green mulch applications to cupuaçu trees can be based on N dynamics of individual green mulch species. Results demonstrated that residue quality, not quantity, was the dominant factor affecting the rate of N release from leaves and soil N mineralization in a controlled environment. In the field, complex N cycling and other factors, including soil fauna, roots, and microclimatic effects, had a stronger influence on available soil N than residue quality.

The pgip family in soybean and three other legume species: evidence for a birth-and-death model of evolution

Background Polygalacturonase-inhibiting proteins (PGIPs) are leucine-rich repeat (LRR) plant cell wall glycoproteins involved in plant immunity. They are typically encoded by gene families with a small number of gene copies whose evolutionary origin has been poorly investigated. Here we report the complete characterization of the full complement of the pgip family in soybean (Glycine max [L.] Merr.) and the characterization of the genomic region surrounding the pgip family in four legume species. Results BAC clone and genome sequence analyses showed that the soybean genome contains two pgip loci. Each locus is composed of three clustered genes that are induced following infection with the fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary, and remnant sequences of pgip genes. The analyzed homeologous soybean genomic regions (about 126 Kb) that include the pgip loci are strongly conserved and this conservation extends also to the genomes of the legume species Phaseolus vulgaris L., Medicago truncatula Gaertn. and Cicer arietinum L., each containing a single pgip locus. Maximum likelihood-based gene trees suggest that the genes within the pgip clusters have independently undergone tandem duplication in each species. Conclusions The paleopolyploid soybean genome contains two pgip loci comprised in large and highly conserved duplicated regions, which are also conserved in bean, M. truncatula and C. arietinum. The genomic features of these legume pgip families suggest that the forces driving the evolution of pgip genes follow the birth-and-death model, similar to that proposed for the evolution of resistance (R) genes of NBS-LRR-type.