Tropical Deciduous Tree Research Articles

Nutraceutical potential of Moringa oleifera

Northern India, south of the Himalayas, is inhabited to the largest habitat of M. oleifera, a tropical deciduous tree that belongs to the Moringa family. M. oleifera includes a variety of nutrients, including protein, vitamin A, minerals, essential amino acids, flavonoids, and isothiocyanates. Extracts of M. oleifera have a number of health benefits, including anti-inflammatory, antioxidant, anti-carcinogenic, hepatoprotective, neuroprotective, hypoglycemic, and lipid-lowering properties. The health advantages of M. oleifera are due to its phytochemicals, including flavonoids and isothiocyanates. This article is a review that concluded studies on M. oleifera’s bioactivity and pharmacological processes in the prevention and treatment of chronic illnesses. These disorders include inflammatory diseases, neuro-dysfunctional diseases, diabetes, and cancer. Studies on Moringa oleifera are summarized in this review, focusing on taxonomy, cultivation, nutritional characteristics, medical applications and value-added products.

Water consumption during a leafless period in a dry season in three deciduous tropical timber species

Besides mechanical protection and sugar transport through phloem, barks also transpire some amount of water. Bark transpiration may be a driving force to keep water flux during the leafless period among tropical deciduous trees, but has been hardly investigated. In the current investigation we used the sap flow data to assess the water consumption during leaf loss initiation, total leaf loss period, and leaf flush period in three economically important tropical deciduous timber species i.e, Anogeissus acuminata, Dipterocarpus tuberculatus and Tectona grandis. Eight trees of each species were measured using Granier’s heat dissipation sensors, with the circumference ranging from 59 cm to 172 cm (mean 59.84 cm) across the three species. The phenological observation for canopy leaves was also carried out on weekly basis. During the completely leafless period, a significant amount of water flux was detected in all three species, which was correlated with vapor pressure deficit (VPD), and light intensity. The whole tree daily mean water consumption during this leaf-less, flower-less and fruit-less period, mainly due to bark transpiration was around 8–14 kg across the three species. It was about 7 to 18 % of the mean whole-tree daily transpiration in the fully foliated canopies during a typical wet-season period. This water flux was supported by sufficient soil moisture as indicated by the pre-dawn leaf water potential higher than –0.4 MPa in the three species. Further, a significant and positive relationship (R2 = 0.32, P < 0.005) was found between tree circumference and whole-tree water consumption during the leaf-less period. The total stand-level water consumption during the leaf-less period ranged from 13 mm to 26.8 mm on a 30 days basis across the three species. Such water flux mainly driven by bark transpiration could have a significant role in maintaining the hydraulic integrity of trees in the dry season, although it could reduce xylem water potential to a risky level of hydraulic dysfunction during a prolonged drought or on dry sites. The study is the first report on bark transpiration in intact trees, scaled to the stand-level, which should be included in the modeling of hydraulic function of plant and ecosystem hydrology.

Recent developments in Moringa oleifera Lam. polysaccharides: A review of the relationship between extraction methods, structural characteristics and functional activities.

Moringa oleifera Lam. (M. oleifera Lam) is a perennial tropical deciduous tree that belongs to the Moringaceae family. Polysaccharides are one of the major bioactive compounds in M. oleifera Lam and show immunomodulatory, anticancer, antioxidant, intestinal health protection and antidiabetic activities. At present, the structure and functional activities of M. oleifera Lam polysaccharides (MOPs) have been widespread, but the research data are relatively scattered. Moreover, the relationship between the structure and biological activities of MOPs has not been summarized. In this review, the current research on the extraction, purification, structural characteristics and biological activities of polysaccharides from different sources of M. oleifera Lam were summarized, and the structural characteristics of purified polysaccharides were focused on this review. Meanwhile, the biological activities of MOPs were introduced, and some molecular mechanisms were listed. In addition, the relationship between the structure and biological activities of MOPs was discussed. Furthermore, new perspectives and some future research of M. oleifera Lam polysaccharides were proposed in this review.

First report of Fusarium oxysporum causing damping-off of tree bean (Parkia timoriana) seedlings in Northeastern India

Tree bean (Parkia timoriana), is an important multipurpose leguminous tropical deciduous tree species widely grown in the Northeastern states of India. The occurrence of the high incidence of damping-off (86.19%) disease was observed in tree bean nursery grown in Umiam, Meghalaya, a state in Northeastern India. Therefore, a systematic study was undertaken to record the symptoms and characterize the morphological features, the taxonomy of pathogen causing damping-off disease of P. timoriana and confirm it by pathogenicity assay. The infected seeds exhibited typical symptoms of covering with whitish mycelium and cotyledons were completely rotten in later stages of infection and emitted foul odour. Infected seedlings exhibited the symptoms of root rot followed by wilting, dried stem, and complete mortality of the seedlings. The pathogen isolated from the rotten seeds and wilted seedlings consistently showed the association of Fusarium oxysporum and its identity was confirmed based on morphological characteristics and sequences of ITS-rDNA and TEF genomic regions. Five representative isolates (TBSR 1 to 5) exhibited high similarity (>98%) to the known authentic gene sequence of F. oxysporum. The pathogenicity test produced similar to natural symptoms of wilt at 30 days after inoculation, confirming the etiological association of Fusarium oxysporum. To the best of our knowledge, this is the first to report on F. oxysporum causing damping-off disease of P. timoriana in India and worldwide.

Projecting the future vegetation–climate system over East Asia and its RCP-dependence

The future vegetation–climate system over East Asia, as well as its dependence on Representative Concentration Pathways (RCPs), is investigated using a regional climate–vegetation model driven with boundary conditions from Flexible Global Ocean–Atmosphere–Land System Model: Grid-point Version 2. Over most of the region, due to the rising CO2 concentration and climate changes, the model projects greater vegetation density (leaf area index) and gradual shifts of vegetation type from bare ground to grass or from grass to trees; the projected spatial extent of the vegetation shift increases from RCP2.6 to RCP8.5. Abrupt shifts are projected under RCP8.5 over northeast China (with grass replacing boreal needleleaf evergreen trees due to heat stress) and India (with tropical deciduous trees replacing grass due to increased water availability). The impact of vegetation feedback on future precipitation is relatively weak, while its impact on temperature is more evident, especially during DJF over northeast China and India with differing mechanisms. In northeast China, the projected forest loss induces a cooling through increased albedo, and daytime high temperature (Tmax) is influenced more than nighttime low temperature (Tmin); in India, increased vegetation cover induces an evaporative cooling that outweighs the warming effect of an albedo decrease in DJF, leading to a weaker impact on Tmax than on Tmin. Based on a single model, the qualitative aspects of these results may hold while quantitative assessment will benefit from a follow-up regional model ensemble study driven by multiple general circulation models.

Effects of herbivory and its timing on reproductive success of a tropical deciduous tree.

The implications of herbivory for plant reproduction have been widely studied; however, the relationship of defoliation and reproductive success is not linear, as there are many interacting factors that may influence reproductive responses to herbivore damage. In this study we aimed to disentangle how the timing of foliar damage impacts both male and female components of fitness, and to assess when it has greater impacts on plant reproductive success. We measured herbivore damage and its effects on floral production, male and female floral attributes as well as fruit yield in three different phenological phases of Casearia nitida (Salicaceae) over the course of two consecutive years. Then we tested two models of multiple causal links among herbivory and reproductive success using piecewise structural equation models. The effects of leaf damage differed between reproductive seasons and between male and female components of fitness. Moreover, the impact of herbivory extended beyond the year when it was exerted. The previous season's cumulated foliar damage had the largest impact on reproductive characters, in particular a negative effect on the numbers of inflorescences, flowers and pollen grains, indirectly affecting the numbers of infructescences and fruits, and a positive one on the amount of foliar damage during flowering. For perennial and proleptic species, the dynamics of resource acquisition and allocation patterns for reproduction promote and extend the effects of herbivore damage to longer periods than a single reproductive event and growing season, through the interactions among different components of female and male fitness.

Isolation, identification and quantification of gallic acid (gallotannins) through HPTLC in leaf galls of Madhuca longifolia (Koenig) j.f. Macb

Plant galls (cecidia) are pathologically produced cells, tissues, or organs of plants that have developed by hypertrophy and hyperplasia of plant tissues under the effect of gall causing organisms. Madhuca longifolia (Koenig) j.f Macb. is an economically and medicinally very important plant of the family Sapotaceae. It is a tropical mixed deciduous tree. Various galls due to insect infestation are found on almost all tree species. Leaf galls of Madhuca longifolia induced by insects of order Diptera and Hymenoptera represent a unique pattern of chemical perturbations which normally do not occur in normal leaf. During the present investigation, an accurate, fast and easy HPTLC method was followed for quantification of gallic acid occur in the normal leaf and dried leaf galls of the Madhuca longifolia plant. The protocol followed in this study resulted in an intense peak and was able to give a good resolution of gallic acid from normal leaf and galled tissues of Madhuca longifolia (Koenig) j.f. Macb. Adaxial leaf gall induced by insect Mohwadiplosis Orientalis Rao belonging to Diptera class, Marginal gall induced by another Dipteran and vein gall by chalcidoiid Hymenopteran class of insect. Variation in Gallic acid present in normal leaf and leaf galls of Madhuca longifolia was critically reported. It was found that Gallic acid content increased almost two folds in gall tissues as compared to normal leaf tissue. Galled leaf (Dipteran adaxial gall) had a maximum amount of Gallic acid (344.4 ng) while in normal leaf and another leaf galls had less amount of gallic acid was found (180ng). This study is of practical importance because gallic acid is the most important active phenolic acid, which may be correlated with post-infection biochemical defense. Compound gallic acid has been reported for the first time from leaf galls of Madhuca longifolia (Koenig) j. f. Macb. Plant in the study.

Allometric scaling laws linking biomass and rooting depth vary across ontogeny and functional groups in tropical dry forest lianas and trees

There are two theories about how allocation of metabolic products occurs. The allometric biomass partitioning theory (APT) suggests that all plants follow common allometric scaling rules. The optimal partitioning theory (OPT) predicts that plants allocate more biomass to the organ capturing the most limiting resource. Whole-plant harvests of mature and juvenile tropical deciduous trees, evergreen trees, and lianas and model simulations were used to address the following knowledge gaps: (1) Do mature lianas comply with the APT scaling laws or do they invest less biomass in stems compared to trees? (2) Do juveniles follow the same allocation patterns as mature individuals? (3) Is either leaf phenology or life form a predictor of rooting depth? It was found that: (1) mature lianas followed the same allometric scaling laws as trees; (2) juveniles and mature individuals do not follow the same allocation patterns; and (3) mature lianas had shallowest coarse roots and evergreen trees had the deepest. It was demonstrated that: (1) mature lianas invested proportionally similar biomass to stems as trees and not less, as expected; (2) lianas were not deeper-rooted than trees as had been previously proposed; and (3) evergreen trees had the deepest roots, which is necessary to maintain canopy during simulated dry seasons.

Assessment of anti-oxidant activity of Ficus benghalensis leaves: an In-vitro design

Background: Medicinal plants represent a rich source of natural anti-oxidants. The traditional medicine involves the use of different plant extracts of bioactive constituents. Ficus benghalensis is a large evergreen tree found throughout India. It is commonly called Banyan tree. It is used in traditional system of medicine like Ayurveda and homoeopathy. Ficus is a huge tropical deciduous or evergreen tree with more than 800 species.&#x0D; Objective: Anti-oxidant effect of ethnomedicinal important plant species Ficus benghalensis (Family-Moraceae) was screened. The aim of this study was to assess the in-vitro potential of methanolic extract of Ficus benghalensis leaves as a natural anti-oxidant.&#x0D; Method: Assessment of in vitro anti-oxidant activity of methanolic leaves extract of Ficus benghalensis was determined by DPPH free radical scavenging assay.&#x0D; Results: The methanolic extract of Ficus benghalensis leaves demonstrates a remarkable amount of phenolic content (54 μg/ml of GAE/100gm of extract) by using Folin-ciocalteu reagent. In-vitro anti-oxidant activity of methanolic leaves extract of Ficus benghalensis was determined by DPPH free radical scavenging assay, which showed significant anti-oxidant activity compared to standard anti-oxidant (ascorbic acid). A direct correlation between total phenol and anti-oxidant activity indicates polyphenols are the main anti-oxidants.&#x0D; Conclusion: These findings suggest the excellent medicinal bio-activity of Ficus benghalensis and explain the popularity of this plant in the folk medicine as a remedy for different disorders, thus supporting its folklore application as preventive remedy as an anti-oxidant. The present study shows that Ficus benghalensis leaves have radical scavenging activity and can be considered as good sources of natural anti-oxidants for medicinal and commercial uses.&#x0D; Keywords: Ficus benghalensis, anti-oxidant, DPPH scavenging activity, Folin-ciocalteu reagent.

Moringa oleifera Leaf Petroleum Ether Extract Inhibits Lipogenesis by Activating the AMPK Signaling Pathway.

In recent years, obesity has become a key factor affecting human health. Moringa oleifera Lam. is a perennial tropical deciduous tree, which is widely used in human medicine due to its nutritional and unique medicinal value. It has a cholesterol-lowering effect, but its mechanism of action is unclear. In this study, we elucidated the inhibitory effect of M. oleifera leaf petroleum ether extract (MOPEE) on lipid accumulation by in vitro and in vivo experiments, and we described its mechanism of action. MOPEE suppressed adipogenesis in 3T3-L1 adipocytes in a dose-dependent manner and had no effect on cell viability at doses up to 400 μg/ml. Furthermore, MOPEE (400 μg/ml) significantly downregulated the expression of adipogenesis-associated proteins [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding proteins α and β (C/EBPα and C/EBPβ), and fatty acid synthase (FAS)] and upregulated the expression of a lipolysis-associated protein [hormone-sensitive lipase (HSL)] in 3T3-L1 adipocytes. Additionally, MOPEE (400 μg/ml) significantly increased the degree of phosphorylation of AMP-activated protein kinase α (AMPKα) and acetyl-CoA carboxylase (ACC). An AMPK inhibitor reversed the MOPEE-induced activation of AMPKα and ACC in 3T3-L1 adipocytes. Animal experiments showed that, in high-fat diet (HFD) mice, MOPEE [0.5 g/kg body weight (BW)] effectively decreased BW; relative epididymal, perirenal, and mesenteric fat weight and fat tissue size; and hepatic fat accumulation. Furthermore, MOPEE markedly reduced the serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and aspartate aminotransferase (AST). Moreover, MOPEE significantly downregulated the expression of adipogenesis-associated proteins (PPARγ and FAS) and upregulated the expression of a lipolysis-associated protein [adipose triglyceride lipase (ATGL)] in HFD mice hepatic and epididymal fat tissue. Additionally, MOPEE markedly increased the degree of phosphorylation of AMPKα and ACC in HFD mice hepatic and epididymal fat tissue. Following ultrahigh-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) analysis, three phytocompounds (isoquercitrin, chrysin-7-glucoside, and quercitrin) were identified as compounds with relatively high levels in MOPEE. Among them, quercitrin showed excellent fat accumulation inhibitory activity, and the three compounds had synergistic effects in inhibiting adipogenesis. Taken together, MOPEE inhibits fat accumulation by inhibiting the adipogenesis and promoting the lipolysis, and this process is related to AMPK activation.

Characterization of a novel polysaccharide isolated from Phyllanthus emblica L. and analysis of its antioxidant activities.

Phyllanthus emblica L. is a tropical deciduous tree producing edible berries with potential medicinal value. In this study, a novel water-soluble phyllanthus emblica polysaccharide (PEP) from the berries was isolated by precipitation and purification, and analyzed for its structure features. The results showed that PEP was a α-pyran acidic heteropolysaccharide with a molecular weight of 1.31 × 105Da, which included galacturonic acid, galactose, rhamnose, and arabinose with a molar ratio of 3.21:6.59:1:0.23. Furthermore, the antioxidant activities of PEP were determined and showed remarkable antioxidant capacities in DPPH, superoxide anion- and hydroxyl-radical scavenging, ferric-reducing antioxidant power, and lipid peroxidation inhibition. This work indicated that PEP as a natural antioxidant agent from the berries of Phyllanthus emblica L. had potential application for developing valuable nutraceutical in food industry.

Seed dispersal of a tropical deciduous Mahua tree, Madhuca latifolia (Sapotaceae) exhibiting bat-fruit syndrome by pteropodid bats

Pollination and seed dispersal are two important phases of the reproductive cycle in plants and are usually performed by different groups of animal taxa in tropics. However, in Mahua tree, Madhuca latifolia (Sapotaceae) both pollination and seed dispersal are predominantly performed by pteropodid bats. We report the foraging and seed dispersal strategies of three sympatric pteropodid bats, Cynopterus sphinx, Rousettus leschenaultii and Pteropus giganteus, during two successive fruiting seasons of M. latifolia. These sympatric fruit bats exhibited spatio-temporal variation while foraging and consumed fleshy mesocarp of fruits and discarded the seeds. Fruit processing time corresponded to the size of the bat species (P. giganteus > R. leschenaultii > C. sphinx); the larger the bat, the more number of fruits they consumed. P. giganteus predominantly consumed the fruits in situ (87% of the times). However, during peak foraging hours, when intraspecific aggressive interactions were high, these bats flew away with fruits from the parent tree (13%), and transported seeds to longer distances (at a time, which they carried = 7.2 km). On the contrary, R. leschenaultii and C. sphinx plucked one fruit at a time and carried to their feeding roosts for consumption. The feeding roosts of medium-sized fruit bat R. leschenaultii were located farther than that of the small-sized C. sphinx, i.e., 52.81 m and 34.18 m, respectively. Comparison of seed germination rates showed no significant variation between bat-dispersed seeds (R. leschenaultii: 95% and C. sphinx: 90%) and control seeds (manually extracted: 90%). As intact fruits did not germinate, mesocarp removal and mobility of seeds away from the parent tree were the main advantages gained by M. latifolia from the foraging bats suggesting the existence of a resource−service mutualism between the fruit bats and bat fruits.

Leaf size and specific leaf area of tropical deciduous trees increase with elevation in soil moisture content

A functional trait ndash based approach provides insight into the functional variations between and within tropical deciduous forests across large gradients of SMC To test this hypothesis we selected nine forest fragment sites in the tropical deciduous forests of India which exhibited significant variations in SMC At all nine sites we measured leaf area LA and specific leaf area SLA of the four deciduous tree species viz Buchanania cochinchinensis Diospyros melanoxylon Lagerstroemia parviflora and Terminalia tomentosa commonly observed in the forest region We recorded significant differences for LA and SLA for the four deciduous tree species across the nine study sites in a gradient of SMC The inter species and within species differences were also significant LA and SLA of the four tree species exhibited strong positive linear relationships with SMC across the nine sites These variations in functional traits were mainly controlled by SMC We suggest that LA and SLA are important functional traits for detecting the effects of variations in SMC on the physiology and distribution of trees in tropical deciduous forests LA and SLA are the key functional traits which are linked with major ecosystem processes and proper research on these traits of the deciduous trees could help in categorizing tree communities for the sustainable development of the tropical deciduous forest ecosystems

Polyphenolics from Albizia harveyi Exhibit Antioxidant Activities and Counteract Oxidative Damage and Ultra-Structural Changes of Cryopreserved Bull Semen.

Albizia harveyi is a tropical deciduous tree, found across South and Eastern Africa and widely used in traditional medicine. The leaf extract ameliorated the damaging effects of the frozen-thawing process in cryopreserved bull semen. In a dose-dependent pattern, sperm motility, viability, and membrane integrity were improved compared to the untreated control. Furthermore, the extract increased the percentage of viable sperm cells and reduced the percentages of early apoptotic and apoptotic sperm cells as well as the damage in sperm ultra-structure. These activities are in agreement with the robust antioxidant properties in vitro and in the seminal fluid as observed in the total antioxidant capacity and the lipid peroxidation parameter malondialdehyde. LC-MS yielded 35 compounds. The extract was dominated by quercetin-O-galloyl-hexoside and quercetin-O-pentoside, along with other flavonoid glycosides. The polyphenols are probably responsible for the observed activities. In conclusion, the current findings show that A. harveyi leaves are rich in bioactive polyphenols with functional properties, validating its traditional use.

More sensitive response of crown conductance to VPD and larger water consumption in tropical evergreen than in deciduous broadleaf timber trees

The differences in crown conductance sensitivity (m) to vapor pressure deficit (VPD) and water consumption between tropical evergreen and deciduous tree are not well-understood despite the importance of such information for the development of plantation and water-resource management strategies in regions that experience seasonal drought and increasing water deficits. To this end, during the wet season we measured sap flow in 60 individual trees representing 21 tropical angiosperm broadleaf timber species (11 evergreen and 10 deciduous) growing in plantations in a marginal tropical area of southwestern China. The results showed that m was strongly correlated with reference crown conductance (Gcref) at 1kPa VPD across all species, with a slope value of 0.46, which was significantly different from the proposed theoretical value of 0.6, suggesting the study species as anisohydric. The m was positively correlated with tree diameter at the height of 1.3m (diameter at breast height, DBH) but for a given DBH, m was significantly higher in evergreens than in deciduous trees. Further, whole-tree mean daily water consumption was strongly and positively correlated with DBH, but at a given DBH, evergreen species exhibited larger water consumption than deciduous species. Vessel diameter (related to xylem hydraulic conductance) and sapwood area were also positively correlated with DBH, and evergreen species had significantly larger sapwood area than deciduous species at a given DBH. In conclusion, we found that 1) crown conductance of evergreen trees is more sensitive to VPD compared to deciduous species and 2) evergreen trees consume more water than deciduous trees, partly because of having higher peak transpiration rate and, larger sapwood area (i.e., larger xylem area for water transport and storage). Therefore, we suggest that in tropical regions associated with seasonal drought timber plantations with more deciduous species could potentially be considered as a management possibility for achieving a balance between timber production and water conservation, even in the wet season, which needs to be tested at the plantation level.

Using satellite data to improve the leaf phenology of a global terrestrial biosphere model

Abstract. Correct representation of seasonal leaf dynamics is crucial for terrestrial biosphere models (TBMs), but many such models cannot accurately reproduce observations of leaf onset and senescence. Here we optimised the phenology-related parameters of the ORCHIDEE TBM using satellite-derived Normalized Difference Vegetation Index data (MODIS NDVI v5) that are linearly related to the model fAPAR. We found the misfit between the observations and the model decreased after optimisation for all boreal and temperate deciduous plant functional types, primarily due to an earlier onset of leaf senescence. The model bias was only partially reduced for tropical deciduous trees and no improvement was seen for natural C4 grasses. Spatial validation demonstrated the generality of the posterior parameters for use in global simulations, with an increase in global median correlation of 0.56 to 0.67. The simulated global mean annual gross primary productivity (GPP) decreased by ~ 10 PgC yr−1 over the 1990–2010 period due to the substantially shortened growing season length (GSL – by up to 30 days in the Northern Hemisphere), thus reducing the positive bias and improving the seasonal dynamics of ORCHIDEE compared to independent data-based estimates. Finally, the optimisations led to changes in the strength and location of the trends in the simulated vegetation productivity as represented by the GSL and mean annual fraction of absorbed photosynthetically active radiation (fAPAR), suggesting care should be taken when using un-calibrated models in attribution studies. We suggest that the framework presented here can be applied for improving the phenology of all global TBMs.

Ethnobotanical value of dry, fallen ovaries of Bombax ceiba L. (Bombacaceae: Malvales)

In the tropics, the traditional ecological knowledge regarding utilization of diverse Non Timber Forest Products (NTFPs) available with different human communities remains under-explored. Though not on an organized scale, the collection and sale of various NTFPs, help the members of tropical rural communities to sustain themselves. Bombax ceiba, a tropical moist deciduous tree has various ethnobotanical values. Semul gum is edible and possesses medicinal value. Immature fruits of this tree have value as an expectorant, stimulant and diuretic. Extracts of young roots are used for treating dysentery. Now the dry, fallen ovaries of this tree species have a new commercial value, and are being widely collected and traded by some local herbalists in Thrissur District of Kerala.

Micropropagation of Anacardiaceae species of economic importance: advances and future prospects

The Anacardiaceae family comprises tropical and subtropical deciduous trees with growing economic potential namely, Pistacia vera L. (pistachio), Mangifera indica L. (mango), Anacardium occidentale L. (cashew), and Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro (marula). The rich gene pool offered by their respective wide genetic diversity as well as the greater adaptation to semi-arid environments makes these species ideal candidates for the development of future commercial cultivars. Some notable achievements have been recorded in the micropropagation of these Anacardiaceae species in the order M. indica > P. vera > A. occidentale > S. birrea subsp. caffra. This review highlights advances, challenges, and future prospects in micropropagation research of these Anacardiaceae family members for the past three decades. In addition, the review discusses the potential of liquid cultures and synthetic seed encapsulation technologies in the development of future research strategies.

The Population Ecology of Two Tropical Trees, Brachychiton diversifolius (Malvaceae) and Bombax ceiba (Bombaceae), Harvested by Indigenous Woodcarvers in Arnhem Land, Australia

We describe the population ecology of two tropical deciduous trees, Bombax ceiba leiocarpum A. Robyns and Brachychiton diversifolius R. Br., which are in high demand for Indigenous sculpture production in Arnhem Land, Australia. We monitored tagged populations of both species at two locations for 2years to examine their reproduction, growth, and survival rates and their response to harvest. Both species have similar life histories: they reproduce during the dry season (June-November) producing a high seed load, seed predation was high, seeds did not survive in the soil past the following wet season to form a seed bank, and germination rates were low and variable for both species. Average annual circumference growth rates were 1.07cmyear(-1) for B. ceiba and 0.98cmyear(-1) for B. diversifolius, with most of the growth occurring during the early wet season. Most (65-88%) of the harvested B. ceiba and B. diversifolius stems coppiced. Coppice and stem size class were the main factors influencing tree growth rates with coppice stems growing up to six times faster than similar sized non-coppice stems. The survival of B. ceiba and B. diversifolius stems was size class dependent and affected by local site factors (e.g. fire and other disturbances) so that the smaller size classes had a low probability of survival. Given the resprouting potential of both species, their wild harvest is likely to have only minimal local impact on wild populations. However, further population modelling is required to determine whether the small and disjunct B. ceiba populations can sustain harvesting at current levels.

Traits with ecological functions

Traits with ecological functions