A revision of the genus Sindora (Fabaceae, Detarioideae) in Peninsular Malaysia and Singapore

Sindora Miq. is a genus of large legume trees found mainly in tropical and subtropical forests from southern China, continental Southeast Asia, and West and Central Malesia. A revision of Sindora in Peninsular Malaysia and Singapore is presented with updated descriptions and distributions. The data are derived from a comprehensive study of herbarium specimens from Peninsular Malaysia and Singapore, together with field observations of individuals growing in natural populations in Singapore. Five species are recorded from Peninsular Malaysia. Four species are recorded from Singapore, all of which also occur in Peninsular Malaysia. Sindora velutina Baker, only recently recorded for Singapore but at the same time noted to be presumed nationally extinct, is reported here as rediscovered. Lectotypes of Sindora siamensis Teijsm. ex Miq. and Sindora velutina are designated here. A second step lectotype is designated for Sindora wallichii Benth. New global-level conservation assessments are proposed for Sindora echinocalyx Prain, Sindora siamensis and Sindora wallichii Benth., while provisional national-level conservation assessments for each species are also reported. Four species of Sindora in Peninsular Malaysia are reported as Least Concern both globally and within Peninsular Malaysia; Sindora siamensis is reported as Least Concern globally but is presumed Nationally Extinct in Peninsular Malaysia. In Singapore all four species of Sindora are reported as Critically Endangered.

Diversity of Rhizobia and Importance of Their Interactions with Legume Trees for Feasibility and Sustainability of the Tropical Agrosystems

Symbiotic biological nitrogen fixation (BNF) is a complex process that involves rhizobia, a diverse group of α and β-proteobacteria bacteria, and legume species. Benefits provided by BNF associated with legume trees in tropical environments include improvements to efficiency of nitrogen (N) use, increase of soil carbon sequestration, stabilization of soil organic matter, decrease of soil penetration resistance, and improvement of soil fertility. All these benefits make BNF a crucial ecosystem service to the sustainability of tropical agriculture. Due to the importance of this ecological process and the high diversity of rhizobia, these bacteria have been extensively characterized worldwide. Currently, over 400 species of rhizobia are known, distributed into seven families. In the humid tropics, Leucaena leucocephala, Acacia mangium, Gliricidia sepium, and Clitoria fairchildiana are four of the most common species used by family farmers to create sustainable agricultural systems. These four legumes perform symbiosis with different groups of rhizobia. Exploring BNF could help to enable sustainable intensification of agriculture in the humid tropics, mainly because it can increase N use efficiency in an environment where N is a limiting factor to plant growth.

Evaluating Soil Organic Carbon Sequestration Potential of Tree Species in Subtropical and Humid forest of Brahmaputra Valley, Assam

Soil organic carbon sequestration potential of different tree was analyzed in every year. Five years after plantation average soil organic carbon was recorded highest under fast growing non legume trees (1.82 %) followed by medium growing (1.72 %) and then slow growing (1.60 %). SOC sequestration potential of legume tree species was significantly lower. It was 1.80 % under fast growing legumes, 1.58 % in medium growing and 1.55 % in slow growing legume trees. On individual comparison of non legume trees, Anthocephalus chinensis found to sequester more (1.98%) carbon as soil organic carbon followed by Trewia nudiflora (1.66%), Alstonia scholaris (1.62%) and Lagerstroemia.speciosa (1.57%). Lowest soil organic carbon sequestration was found under Chukrasia. tabularis (1.26%). No significant difference was observed in SOC sequestration potential between Dipterocarpus retusus, Artocarpus chaplasha, Ficus hispida, Mallotus albus, Litsea nitida, Castanopsis indica, Taphrosia candida, Albizzia procera and A. lebbek.

CARBON STOCKS IN MINED AREA RECLAIMED BY LEGUMINOUS TREES AND SLUDGE

ABSTRACT Few studies have been carried out on aboveground (or belowground) and soil/substrate C accumulation in severely degraded areas, such as mined areas. The present study was developed in order to find a recovery strategy for a mined area and characterize its potential for C sequestration by planting two nitrogen-fixing Brazilian tree species (Mimosa caesalpiniifolia Benth and M. bimucronata (DC.) O. Kuntze). Sewage sludge was included in the experimental design. An experiment under randomized block condition and 2 x 5 factorial design with four replications were defined and carried out, in Rio de Janeiro State, Brazil. The treatments consisted of a combination of both tree species and five sewage sludge doses (0, 2.85; 5.70; 11.40 and 22.80 Mg ha-1). M. caesalpiniifolia grows better (p<0.05) in reclaimed areas than M. bimucronata, even though neither the height nor the basal area of both species responded to the sludge application. Carbon stock in the tree trunks differ between species (27.3 and 14.3 Mg ha-1, for M. caesalpinifolia and M. bimucronata, respectively), and was influenced by the doses of sewage sludge, whereas the soil carbon stock (0-10 cm) did not differ between species and doses (12.0 and 12.2 Mg ha-1, for M. caesalpiniifolia and M. bimucronata, respectively). Soil fertility in the degraded site was found to be improved by legume trees six years after planting, with a small influence of the sewage sludge level. Mined areas recovered with legume trees can sequestrate significant amounts of C both in aboveground biomass and soil in a short period of time.

Desarrollo arquitectónico de tres especies de Acacia

Studies about the vegetative development of Legume trees are relatively rare. In order to infer about the evolution of different development patterns a study of taxonomically related species is requiered. We analyzed three species of Acacia (A . collinsii, A. cedilloi and A. dolichoslachya) which according to preliminary observations show branching patterns as defined in the architectural model of Troll or Champagnat in order to answer the question which is the evolutionary relation between these models. We describe the development pattern of these species and found that a combination of architectural models is needed to do so. We found that mixed plagiotropic axes in A. collinsii are relayed by orthotropic axes during development and open a discussion to the evolutionary origen of the mixed axis.