Pod production, and dasometric variables, of the tree Senna spectabilis (Fabaceae) in a tropical dry forest / Producción de vainas, y variables dasométricas, del árbol Senna spectabilis (Fabaceae) en un bosque seco tropical

Introduction: Senna spectabilis is a multipurpose pantropical tree, used in agroforestry systems. Objective: To determine pod production (Pp) and their relationship with dasometric variables in S. spectabilis in the tropical dry forest. Methods: From August 2016 to February 2017, thirty trees in production stage were randomly selected. The random selection was formed of the more isolated trees from the total dispersion. The trees were monitored at the beginning and end of the study period, to determine dasometric measurements such as total height (Th), height to the first branch (Hb), crown height (Ch), Stem diameter (at 0.2 m height from the ground) (Db), crown diameter (Cd), and crown volume (Cv) measured. Pods were harvested by the researcher with cutting and height cutting tongs when their color began to change. Pearson correlations and univariate and multivariate regression analyses were performed between the dasometric variables and pod production. The potential number of trees/ha (NPa) was calculated by determining the occlusion percentage (Op) and the shadow area/tree (Ca); to estimate the production potential of fruits/ha, the production of fruits/tree was multiplied by (NPa). Results: Th was 6.16 ± 1.23 m, Hb 2.75 ± 0.52 m, Ch 3.41 ± 0.98 m, Db 20.43 ± 4.80 cm, Cd 7.46 ± 1.20 m and Cv 108.43 ± 61.38 m3/tree. There was a significant positive correlation between Hb, Cd, Db, with Pp of 0.592**, 0.592**, and 0.446* respectively. Pp was 32.73 ± 16.13 kg/tree and the dry matter production (MSP) was 17.84 ± 8.80 kg/tree. The result of the multivariate regression indicated that the second-order polynomial model presented best goodness of fit. Op was 73.4 7.92 %, the cup area was 49.3 m2/tree, Ca was 36.2 m2/tree, and NPa was 83 trees. Conclusions: The production of fresh pods/ tree in the S. spectabilis presents a potential in its availability as feed for ruminant or seed production. The potential production of pods in silvopastoral with S. spectabilis could be 2.72 t/ ha, and 1.64 t/ ha of dry pods, this shows the importance of trees and of pods production and nutritional contribution obtained for dry ecosystems.

Introducción: Senna spectabilis es un árbol pantropical multipropósito, utilizado en sistemas agroforestales. Objetivo: Determinar la producción de vainas (Pv) y la relación con las variables dasométricas en S. spectabilis en el bosque seco tropical. El número potencial de árboles/ha (NPa) fue calculado determinando el porcentaje de oclusión (Po) y el área de sombra/árbol (As); para calcular la producción potencial de frutos/ha, la producción de frutos/árbol fue multiplicada por (NPa). Métodos: Desde agosto del 2016 hasta febrero de 2017, treinta árboles en etapa de producción fueron seleccionados al azar, los más aislados del total de árboles dispersos fueron seleccionados, y fueron monitoreados al inicio y al final del período de estudio, para determinar las mediciones dasométricas como la altura total (At), altura a la primera rama (Apr), altura de la copa (Ac), diámetro del tallo (a 0.2 m altura desde el suelo) (Dt), diámetro de la copa (Dc) y volumen de copa (Vc). Las vainas se cosecharon cuando su color comenzó a cambiar. Se realizaron correlaciones de Pearson y análisis de regresión univariada y multivariada entre las variables dasométricas y la producción de vainas. El número potencial de árboles/ha (NPa) se calculó determinando el porcentaje de oclusión (Po) y el área de sombra/árbol (Asa); para estimar el potencial de producción de las vainas/ha, la producción de vainas/árbol se multiplicó por NPa. Resultados: La At fue de 6.16 ± 1.23 m, Apr 2.75 ± 0.52 m, Ac 3.41 ± 0.98 m, Db 20.43 ± 4.80 cm, Dc 7.46 ± 1.20 m y Vc 108.43 ± 61.38 m3/árbol. Existió una correlación positiva significativa entre Apr, Dc, Db, Pv de 0.592**, 0.592 ** y 0.446 * respectivamente. La Pv fue de 32.73 ± 16.13 kg y la producción de materia seca (PMS) fue de 17.84 ± 8.80 kg/árbol. El resultado de la regresión multivariada indicó que el modelo polinomial de segundo orden presentó la mejor bondad de ajuste. El Po de los árboles fue de 73.4 % ± 7.92 %, el área de copa fue de 49.3 m2/árbol, el Asa fue de 36.2 m2/árbol, el NPa fue de 83 árboles. Conclusiones: La producción de vainas frescas/árbol en el S. spectabilis presenta un potencial en la disponibilidad de alimento para los rumiantes o la producción de semillas. El potencial de producción de vainas en u arreglos silvopastoriles podría ser de 2.72 t/ha, y 1.64 t/ha de vainas secas, esto muestra la importancia del árbol de producción de vainas y la contribución nutricional para los ecosistemas secos.

The genus Senna Mill. (Leguminosae: Caesalpinioideae) in a fragment of the Ecological Station Raso da Catarina, Bahia, Brazil / O gênero Senna Mill. (Leguminosae: Caesalpinioideae) em um fragmento da Estação Ecológica Raso da Catarina, Bahia, Brasil

Senna comprises about 300 species with circuntropical distribution, widely represented in the Americas, also occurring in Africa, Australia, Asia and Oceania. The Brazil includes 80 species, of which 27 are endemic, 50 reported from Bahia and 22 recorded from the Caatinga. The floristic survey of Senna in the Ecological Station Raso da Catarina included analysis of specimens collected March 2010 to October 2011. The analyses were supplemented with dried collections from the following herbaria: ALCB, EAC, HRB, HUEFS and MBM. Seven taxa were recorded. The most representative taxa in the area were Senna rizzinii H.S.Irwin & Barneby and S. acuruensis (Benth.) H.S.Irwin & Barneby var. acuruensis. The genus can be found in a variety of environments from preserved to degraded areas and in sandy, sandy-clayey or rocky soils. The taxonomic treatment includes anidentification key, descriptions, illustrations, photos, data of the geographical distribution, reproductive phenology and comments about the taxa.(AU)

Senna inclui cerca de 300 espécies com distribuição circuntropical, amplamente representada nas Américas, ocorrendo ainda na África, Austrália, Ásia e Oceania. O Brasil inclui 80 espécies, dentre estas 27 são endêmicas, 50 são registradas para Bahia e 22 para Caatinga. O levantamento florístico de Senna na Estação Ecológica Raso da Catarina incluiu a análise de espécimes coletados de março de 2010 a outubro de 2011. As análises foram complementadas com coleções dos seguintes herbários: ALCB, EAC, HRB, HUEFS e MBM. Sete táxons foram registrados. Os táxons mais representativos na área foram Senna rizzinii H.S.Irwin & Barneby e S. acuruensis (Benth.) H.S.Irwin & Barneby var. acuruensis. O gênero pode ser encontrado em uma variedade de ambientes de preservados até áreas degradadas e em solos arenosos, argilo-arenosos ou rochosos. O tratamento taxonômico inclui uma chave de identificação, descrições, ilustrações, fotografias, dados de distribuição geográfica, fenologia reprodutiva e comentários sobre os táxons.(AU)

Heteranthery as a solution to the demand for pollen as food and for pollination - Legitimate flower visitors reject flowers without feeding anthers.

Heteranthery, the presence of feeding and pollinating anthers in the same flower, seems to mediate the evolutionary dilemma for plants to protect their gametes and yet provide food for pollinators. This study aims to elucidate the role of heteranthery in the buzz-pollinated Senna reniformis. The fecundity of pollen from long-, medium- and short-sized anthers was determined by hand cross-pollination experiments, and the quantity, size, ornamentation and viability of pollen of different anthers were compared. Rates of flower rejection by bees were measured in anther removal experiments to assess the preferences of flower visitors for feeding or pollinating anthers. Large bees, which were the effective pollinators of self-incompatible S. reniformis, avoided flowers without short feeding anthers, but not those without medium or long anthers. Illegitimate small and medium-sized bees were unresponsive to anther exclusion experiments. Long anthers deposited pollen on the back and short anthers on the venter of large bees. Pollen from long anthers had higher in vitro viability and higher fruit and seed set after cross-pollination than pollen from other sized anthers. Short anthers produce feeding pollen to effective pollinators and long anthers are related to pollination of S. reniformis. Bee behaviour and size was found to directly influence the role of anthers in the 'division of labour'. Only large bee pollinators that carry the pollinating pollen from long anthers in 'safe sites' associated short anthers with the presence of food. In the absence of these larger bee pollinators, the role of heteranthery in S. reniformis would be strongly compromised and its function would be lost.

Ricochet pollination in Senna (Fabaceae) - petals deflect pollen jets and promote division of labour among flower structures.

Naturalists Fritz and Hermann Müller hypothesised that heteranthery often leads to a division of labour into 'feeding' and 'pollinating' stamens; the latter often being as long as the pistil so as to promote successful pollination on the bees' back. In many buzz-pollinated species of Senna, however, the so-called pollinating stamens are short and not level with the stigma, raising the question of how pollen is shed on the bees' back. Here we explore a mechanism called 'ricochet pollination'. We test whether division of labour is achieved through the interaction between short lower stamens and strongly concave 'deflector petals'. We studied the arrangement and morphology of the floral organs involved in the ricochet pollination, functioning of the flowers through artificial sonication and observed the interactions between bees and flowers in the field. The middle stamens are adapted to eject pollen downwards, which can be readily collected on the bee mid legs. Most of the pollen is ejected towards the deflector petal(s). Pollen from this set of stamens is more likely to contribute to pollination. The pollen grains seem to ricochet multiple times against the deflector petals to eventually reach the bee's back. The pollen ricochet mechanism promotes a division of labour by involving additional floral organs, such as petals, reinforcing the Müllers' division-of-labour hypothesis. However, alternative, non-multiexclusive hypotheses could be explored in genus Senna and other angiosperm species.

Avaliação in vitro de propriedades biológicas de Senna occidentalis (L) Link / Evaluation of in vitro biological properties of Senna occidentalis (L) Link

Espécies de Senna são amplamente utilizadas por tribos americanas, africanas e indianas, principalmente para tratar a fraqueza, a constipação, as desordens do fígado e também em preparações tópicas para infecções de pele. A Senna occidentalis (L.) Link é um arbusto perene nativo da América do Sul encontrado em regiões tropicais. Este trabalho avaliou a atividade antimicrobiana de extratos aquosos e hidroalcoólicos de diferentes partes da planta. A atividade antimicrobiana foi estabelecida frente aos microrganismos padrões farmacêuticos por espectrofotometria e técnica de microdiluição. A Escherichia coli apresentou sensibilidade apenas a componentes extraídos das sementes, os quais podem ser de natureza proteica. O espectro mais amplo de atividade antimicrobiana foi obtido com o extrato hidroalcoólico das sementes, principalmente contra Pseudomonas aeruginosa. A toxicidade in vitro utilizando fibroblastos de camundongo indicou que este extrato pode ser um ingrediente biocompatível para formulações de uso tópico. Já o extrato hidroalcoólico de partes aéreas demonstrou ser potencialmente citotóxico.(AU)

Senna species have been widely used by American, African and Indian ethic groups mainly in the treatment of feebleness, constipation, liver disorders and skin infections. Senna occidentalis (L.) Link is a perennial shrub native to South America and indigenous to tropical regions throughout the world. Current study evaluated the antimicrobial activity of aqueous and hydroalcoholic extracts from S. occidentalis prepared from different parts of the plant. Antimicrobial activity was assessed against standard pharmaceutical microorganisms by spectrophotometry and microdilution technique. Escherichia coli was sensitive only to compounds extracted from seeds which may be proteinaceous. A broader antimicrobial spectrum was demonstrated by the hydroalcoholic extract of seeds, mostly against Pseudomonas aeruginosa. The in vitro toxicity using mouse fibroblasts indicated that the extract might be a biocompatible ingredient for topical formulations, while the hydroalcoholic extract of aerial parts demonstrated to be potentially cytotoxic.(AU)

Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae)

The genus Senna (K.Bahuin) Miller (Cassieae) is represented in Argentina by 35 species and several varieties distributed in temperate, tropical and subtropical regions, and presents a high degree of endemism. Some taxa are used for medicine, animal foraging and ornamental purposes. Floral morphology, phases, rewards, attractants, visitors, pollen, reproductive system, P/O ratio, OCI and ISI indexes of enantiostylous Senna corymbosa were analyzed for morphological androecial differentiation and possible related functional differences between stamens groups. The study was carried out over three consecutive flowering seasons in March of 1999, 2000 and 2001, in two populations near the city of Buenos Aires, Argentina. The species has a buzz-pollination syndrome. The pollinators are Bombus atratus that vibrate the stamens, leading to nothotribic or sternotribic deposition of pollen. P/O ratio and pollen production were high thanks to the precise pollinating mechanism that needs a large delivery of pollen to ensure effective pollen deposition. P/O ratio also indicates that the species is xenogamous, although geitonogamy and autogamy (only induced, not spontaneous)were also recorded. The species is self-compatible. There were differences in hand-pollination treatments between long and medium stamens in fruit set, as well as in vitro differential fertility between their pollen grains. Hence, there are morphological and functional androecium differences: the medium stamens play a nutritional role while the long ones play a reproductive one. These differences are reflected in the breeding system. Moreover, differential fertility and enantiostyly may diminish the effects of self-compatibility by partially reducing the contribution of geitonogamy to selfing

Se analizaron la morfología y fases florales, recompensa, atractivos, visitantes, polen, sistema reproductivo, índices OCI e ISI y relación polen/óvulo de la especie enantiostílica Senna corymbosa. El objetivo fue estudiar su biología floral y determinar la posible presencia de diferenciación morfológica en el androceo. Era importante saber si las diferencias morfológicas reflejaban diferencias funcionales entre los grupos de estambres. El estudio se llevó a cabo durante tres estaciones de floración consecutivas en marzo de 1999,2000 y 2001,sobre dos poblaciones presentes en zonas protegidas de la ciudad de Buenos Aires, Argentina. La especie presenta un síndrome de polinización vibrátil (buzz-pollination).Los polinizadores son individuos de Bombus atratus, capaces de vibrar los estambres y extraer polen, el que se deposita nototríbica y/o esternotríbicamente. La relación P/O fue extremadamente elevada, así como la producción de polen. Esto se relaciona con el comportamiento de los visitantes y con la alta precisión del mecanismo de polinización, que requiere una gran cantidad de polen para asegurar su efectiva deposición en el cuerpo del insecto. La relación P/O indica que la especie es xenógama, aunque se registraron también geitonogamia y autogamia inducidas. La especie, por lo tanto, es autocompatible. Se encontraron diferencias en los tratamientos de polinización manual entre estambres largos y medianos en cuanto al establecimiento de frutos, así como una fertilidad diferencial in vitro entre sus tipos polínicos. Existen, así, diferencias morfológicas y funcionales en el androceo: los estambres medianos tienen un papel nutricional mientras que los largos cumplen un papel reproductivo. Estas diferencias se reflejan en el sistema de cruzamiento. Más aún, la fertilidad diferencial y la enantiostilia disminuyen los efectos de la autocompatibilidad reduciendo parcialmente la contribución de la geitonogamia a la endogamia

Floral biology and reproductive system of enantiostylous Senna corymbosa (Caesalpiniaceae).

The genus Senna (K. Bahuin) Miller (Cassieae) is represented in Argentina by 35 species and several varieties distributed in temperate, tropical and subtropical regions, and presents a high degree of endemism. Some taxa are used for medicine, animal foraging and ornamental purposes. Floral morphology, phases, rewards, attractants, visitors, pollen, reproductive system, P/O ratio. OCI and ISI indexes of enantiostylous Senna corymbosa were analyzed for morphological androecial differentiation and possible related functional differences between stamens groups. The study was carried out over three consecutive flowering seasons in March of 1999, 2000 and 2001, in two populations near the city of Buenos Aires, Argentina. The species has a buzz-pollination syndrome. The pollinators are Bombus atratus that vibrate the stamens, leading to nothotribic or stemotribic deposition of pollen. P/O ratio and pollen production were high thanks to the precise pollinating mechanism that needs a large delivery of pollen to ensure effective pollen deposition. P/O ratio also indicates that the species is xenogamous, although geitonogamy and autogamy (only induced, not spontaneous) were also recorded. The species is self-compatible. There were differences in hand-pollination treatments between long and medium stamens in fruit set, as well as in vitro differential fertility between their pollen grains. Hence, there are morphological and functional androecium differences: the medium stamens play a nutritional role while the long ones play a reproductive one. These differences are reflected in the breeding system. Moreover, differential fertility and enantiostyly may diminish the effects of self-compatibility by partially reducing the contribution of geitonogamy to selfing.