Acmena Acuminatissima Research Articles

Analisis Hambatan Perkembangan Stadium Plasmodium Falciparum Terhadap Pemberian Ekstrak Daun Salam Badak (Acmena Acuminatissima) In Vitro

Background: The urgency generated by drug-resistant strains of malaria parasites has accelerated the need to find a new anti-malarial drug. Recent studies have shown that 80% ethanol extract Acmena acuminatissima has suitable antimalarial activities. Aim: To analyze the inhibitory effect of A. acuminatissima extract at the developmental stage of P. falciparum in infected erythrocytes in vitro. Methods: the synchronized culture of P. falciparum was incubated along with A. acuminatissima extract, and compared with negative controls. The effect on parasite growth was determined by observing the level of parasitemia and accumulation of various infective stages seen on thin blood smears after the incubation period of 12, 24, 36, and 48 hours using a light microscope with 1000 times magnification. Results: Within 48 hours of observation the difference was mainly in the proportion of ring-stage which was 2.75% in culture with the test compound and 41.41% in the negative control which showed that ethanol extract of A. acuminatissima inhibited the growth of parasites at the schizont stage into the ring stage. In trophozoite and schizonts stages of culture with test compounds, enlargement of digestive vacuole and vesiculation is obtained. Conclusion: A. acuminatissima inhibits the development of intraerythrocyt parasites at the schizonts stage and induced morphological changes.

Effects of allelopathy and competition for water and nutrients on survival and growth of tree species in Eucalyptus urophylla plantations

Allelopathy and resource competition are considered to be two primary mechanisms responsible for loss of biodiversity in plantations of Eucalyptus species. However, these two processes are usually studied separately, and they have been rarely tested on native woody species. In this study, we used a bioassay to assess sensitivities of twenty broad-leaved tree species on roots, stem growth and seed germination to leaf aqueous extracts of Eucalyptus urophylla S.T. Blake and categorized them into two types: inhibited and uninhibited (including stimulated and unaffected). To compare the relative importance of allelopathy and resource competition, we planted these two species groups into the E. urophylla plantation separately and treated with three gradients of irrigation-nutrients. The results showed that the allelopathic effects of aqueous extract of E. urophylla were species-specific and could be inhibitory, neutral or stimulatory. Compared to the inhibited species, the uninhibited species grew faster and survived better after they were planted in an E. urophylla plantation for approximately 10 years, suggesting that allelopathy from E. urophylla is an important restraining factor on native woody communities. Individuals from both species groups grew faster following higher resource treatment at the early but not the late stage of growth. Saplings did not vary in their survival rates across resource gradients. This indicates that resource competition between E. urophylla and native woody species has only a limited role in reducing the diversity of native species in an E. urophylla plantation. We conclude that allelopathy is more important than resource competition in mediating the reduction in plant biodiversity in E. urophylla plantations. Our study suggests that mixing certain types of species (e.g. Helicia cochinchinensis, Pterospermum lanceaefolium, Cinnamomum burmanni, Machilus chinensis, Acmena acuminatissima and Castanopsis chinensis) in E. urophylla plantations can mitigate against plant diversity loss.

Anthocyanins function as a light attenuator to compensate for insufficient photoprotection mediated by nonphotochemical quenching in young leaves of Acmena acuminatissima in winter

Anthocyanins and nonphotochemical quenching (NPQ) are two important tools that provide photoprotection in plant leaves. In order to understand how plants use these tools for acclimation to changing seasonal conditions, we investigated pigments, antioxidative capacity, and photosynthesis in leaves of an evergreen tree (Acmena acuminatissima) in two contrasting seasons. Young leaves of A. acuminatissima appeared in distinct colors, being light green in summer and red in winter due to the presence of anthocyanins. In the winter young leaves, anthocyanins contributed less than 2% to the antioxidant pool. In the summer, young leaves had higher NPQ than that of mature leaves, but in the winter, they did not derive any NPQ-related advantage over mature leaves. These results suggest that the accumulation of anthocyanins in young leaves in the winter may compensate for the insufficient photoprotection afforded by NPQ and that anthocyanins function as a light attenuator to protect the photochemical apparatus against excess light.

Pigment patterns and photoprotection of anthocyanins in the young leaves of four dominant subtropical forest tree species in two successional stages under contrasting light conditions.

Light-driven subtropical forest succession is a dynamic process in which mesophytic climax communities replace heliophytic ones. Juvenile leaves (particularly mesophytic ones) are sensitive to high irradiances. To determine the photoprotection strategy that juvenile leaves use during subtropical forest succession, anthocyanin accumulation patterns were investigated in the young leaves of two mid-successional dominant trees (i.e., Schima superba and Castanopsis fissa) and two late-successional dominant trees (i.e., Cryptocarya concinna and Acmena acuminatissima) grown in 100% (FL) and 25% (LL) of full sunlight. All four tree species produced anthocyanins in their juvenile leaves when <50% of chlorophylls and carotenoids had developed. Higher anthocyanin concentrations accumulated in the young leaves grown in FL than in those grown in LL and in late-successional than in mid-successional trees. The juvenile leaves of late-successional trees were subjected to higher light-induced photoinhibition than those of mid-successional trees, despite of the fact that the leaves of late-successional trees showed greater non-photochemical quenching than those of mid-successional trees. Under LL conditions, photosystem II excitation pressure (1 - qP) was significantly higher in the juvenile leaves of late-successional trees than those of mid-successional trees. Under either FL or LL conditions, anthocyanin concentrations in juvenile leaves were negatively related to the light compensation point in mature leaves across species. However, anthocyanin concentrations were positively related to the antioxidant capacity of juvenile leaves. These results indicate that anthocyanin accumulation in the juvenile leaves of subtropical dominant trees during forest community succession is a flexible photoprotective response to ambient irradiances according to leaf sensitivity to light.

Nitrogen and phosphorus productivities of five subtropical tree species in response to elevated CO2 and N addition

The productivities of nitrogen and phosphorus (NP and PP) in plants have been greatly altered by increasing atmospheric carbon dioxide concentrations (CO2) and nitrogen (N) deposition. However, studies on this are quite limited in tropical and subtropical forests. We used open-top chambers to examine the NP and PP of five tree species in response to elevated CO2 and N addition in subtropical forests from 2005 to 2009. The five tree species included the slow-growing species (Acmena acuminatissima and Syzygium hancei) and the fast-growing ones (Castanopsis hystrix, Ormosia pinnata and Schima superba). Elevated CO2 increased the NP and PP of C. hystrix. However, the NP and PP of S. hancei were decreased by elevated CO2, and the PP of A. acuminatissima was lowered by elevated CO2 without N addition. N addition had no significant influence on the NP of all tree species, while it increased the PP of S. superba. The changes in the NP and PP were related to those in plant growth. We concluded that C. hystrix and S. superba would benefit from elevated CO2 and N addition, respectively. The results indicate that plant NP and PP in response to elevated CO2 and N addition are species specific. Our findings could have important implications for better understanding the effects of global change on species composition in subtropical forests.

Photosynthetic characteristics and light energy conversions under different light environments in five tree species occupying dominant status at different stages of subtropical forest succession.

In order to reveal the mechanism of succession in subtropical forest along a light gradient, we investigated photosynthetic physiological responses to three light environments in five tree species including a pioneer species Pinus massoniana Lamb., two mid-successional species Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., and two late-successional species Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry) that were selected from Dinghu Mountain subtropical forest, South China. Results showed that, among the three kinds of species in all light conditions (100%, 30% and 12% of full sunlight), the pioneer species had the highest photosynthetic capacity (Amax), light saturation point (LSP), carboxylation efficiency (CE) and maximum utilisation rate of triose phosphate (TPU) that characterised a strong photosynthetic capacity and high carbon dioxide uptake efficiency. However, a higher light compensation point (LCP) and dark respiration (Rd) as well as lower apparent quantum yield (AQY) indicated that the pioneer specie cannot adapt to low light conditions. Mid-successional species had photosynthetic characteristics in between pioneer and late-successional species, but had the greatest effective quantum yield of PSII (ΦPSII) and light use efficiency (LUE, expressed in terms of photosynthesis). In contrast to pioneer and mid-successional species, late-successional species had lower photosynthetic capacity and carbon uptake efficiency, but higher shade tolerance and high-light heat dissipation capacity, as characterised by higher levels of total xanthophyll cycle pigments (VAZ) and de-epoxidation state of xanthophyll cycle (DEPs). These results indicate that photosynthetic capacity decreases along the successional axis and that late-successional species have more responsive heat dissipation capability to compensate for their inferior photosynthetic capacity.

Water-use efficiency of four native trees under CO2enrichment and N addition in subtropical model forest ecosystems

We aimed to evaluate the changes in water-use efficiency (WUE) in native tree species in forests of subtropical China, and determine how coexisting species would be responding to increases in atmospheric carbon dioxide (CO2) concentrations and nitrogen (N) deposition. We used model forest ecosystems in open-top chambers to study the effects of elevated CO2 (ca. 700 µmol mol−1) alone and together with N addition (NH4NO3 applied at 100kg N ha−1year−1) on WUE of four native tree species (Schima superba, Ormosia pinnata, Castanopsis hystrix and Acmena acuminatissima) from 2006 to 2010. Our result indicated that all species increased their WUE when they were exposed to elevated CO2. Although higher WUE was shown in faster-growing species (S. superba and O. pinnata) than that of slower-growing species (C. hystrix and Acmena acuminatissima), the increased extent of WUE induced by elevated CO2 was higher in the slower-growing species than that of the faster-growing species (P < 0.01). The N treatment decreased WUE of S. superba, while the effects on other species were not significant. The interactions between elevated CO2 and N addition increased intrinsic WUE of S. superba significantly (P < 0.001), however, it did not affect WUE of the other tree species significantly. We conclude that the responses of native tree species to elevated CO2 and N addition are different in subtropical China. The species-specific effects of elevated CO2 and N addition on WUE would have important implications on species composition in China’s subtropics in response to global change.

Allelopathic effects of Eucalyptus on native and introduced tree species

Allelopathy is widely considered to be one of the causes of biodiversity reduction in Eucalyptus plantations. However, most research conducted on the allelopathic effects of Eucalyptus is performed in the laboratory with weeds and crops as receptors, which fail to fully reflect natural ecosystems. In this study, we conducted two field trials and a greenhouse trial to assess the influence of soil allelopathy, allelochemical volatilization, and foliage litter decomposition on seed germination and seedling growth of three native (Acmena acuminatissima, Cryptocarya concinna and Pterospermum lanceaefolium) and one introduced (Albizia lebbeck) tree species in a Eucalyptus urophylla and Pinus elliottii plantation. In order to avoid confounding factors relating to management strategies and environmental influences, only one plantation of each species was used for experimentation. In the allelopathy experiment, the root length of the three native species was significantly inhibited in the E. urophylla plantation compared with that in the P. elliottii plantation. In the volatilization experiments, the seedling survival rate of the three native species was greater in the E. urophylla plantation, but significant differences were found for A. acuminatissima and C. concinna. Root length and dry weight of P. lanceaefolium increased significantly in the E. urophylla plantation, in the foliage litter decomposition experiments. There was no significant difference between the two plantations for A. lebbeck, except that the seedling survival rate was greater in the E. urophylla plantation in the foliage litter decomposition experiment. We concluded that allelopathy in the E. urophylla plantation was selective, which inhibited the growth of the native tree species but had no significant influence on the introduced A. lebbeck species. Allelopathy from volatilization and foliage litter decomposition contributed little to the inhibitory effects. We suggest that the introduced nitrogen-fixing species, A. lebbeck could be a potential choice for the establishment of mixed stands with Eucalyptus.

Utilization of lightflecks by seedlings of five dominant tree species of different subtropical forest successional stages under low-light growth conditions

We selected five typical tree species, including one early-successional species (ES) Pinus massoniana Lamb., two mid-successional species (MS) Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils. and two late-successional species (LS) Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry., which represent the plants at three successional periods in Dinghushan subtropical forest succession of southern China. Potted seedlings of the five species were grown under 12% of full sunlight for 36 months. The ES and MS showed the slowest and fastest responses to lightflecks, respectively, which correlated with the rate of stomatal opening. In contrast to P. massoniana and C. concinna, the other three species exhibited a high induction loss. Early-successional species showed the lowest specific leaf area and chlorophyll content, the highest photosynthetic capacity (A(max)) and respiratory carbon losses (R(d)). Compared with ES and MS, LS showed lower A(max) and R(d). The five tree species showed a similar chlorophyll a/b ratio after long-term low-light adaptations. On the other hand, LS had a relatively higher de-epoxidation state to protect themselves from excess light during lightflecks. Our results indicated that (i) slower responses to lightflecks could partially explain why ES species could not achieve seedling regeneration in low-light conditions; (ii) fast responses to lightflecks could partially explain why MS species could achieve seedling regeneration in low-light conditions; and (iii) smaller respiratory carbon losses might confer on the LS species a competitive advantage in low-light conditions.

Changes in leaf nutrient traits and photosynthesis of four tree species: effects of elevated [CO2], N fertilization and canopy positions

Aims Leaf traits of trees exposed to elevated [CO2] in association with other environmental factors are poorly understood in tropical and subtropical regions. Our goal was to investigate the impacts of elevated [CO2] and N fertilization on leaf traits in southern China. Methods Four tree species, Schima superba Gardn. et Champ. (S. superba), Ormosia pinnata (Lour.) Merr (O. pinnata), Castanopsis hystrix AC. DC. (C. hystrix) and Acmena acuminatissima (Blume) Merr. et Perry (A. acuminatissima) were studied in a factorial combination of atmospheric [CO2] (ambient at ;390 lmol mol 1 and elevated [CO2 ]a t;700 lmol mol 1 ) and N fertilization (ambient and ambient + 100 kg N ha 1 year 1 ) in open-top chambers in southern China for 5 years. Leaf mass per unit leaf area (LMA), leaf nutrient concentration and photosynthesis (Asat) were measured. Important Findings Results indicated that leaf traits and photosynthesis were affected differently by elevated [CO2] and N fertilization among species. Elevated [CO2] decreased LMA in all species, while N fertilization did not affect LMA. Leaf mass-based N concentration (NM) was significantly greater in O. pinnata and C. hystrix grown in elevated [CO2] but was lower in S. superba. Leaf mass-based P concentration (PM) was significantly greater in C. hystrix and A. acuminatissima exposed to elevated [CO2] but was lower in S. superba. N fertilization significantly increased PM in O. pinnata but decreased PM in S. superba. Photosynthetic stimulation in O. pinnata, C. hystrix and A. acuminatissima was sustained after 5 years of CO2 fumigation. N fertilization did not modify the effects of elevated [CO2] on photosynthesis. Leaf traits (NM ,N A ,P M ,P A) and light-saturated photosynthesis were decreased from the upper to lower canopy. Canopy position did not alter the responses of leaf traits and photosynthesis to elevated [CO2]. Results suggest that photosynthetic stimulation by elevated [CO2] in native species in subtropical regions may be sustained in the long term.

Light acclimation and HSO3 − damage on photosynthetic apparatus of three subtropical forest species

The effects of long-term (33 months) sun/shade acclimation and short-term (within 10 h) HSO(3) (-) treatment on leaf photosynthetic apparatus were investigated in three subtropical forest plants, Pinus massoniana, Schima superba, and Acmena acuminatissima. After 33 months' growth in two light environments (100 and 12% sunlight), rapid light curves (RLC), chlorophyll fluorescence imaging and chloroplast ultrastructures of three tested species were changed to different degrees. When leaf sections were immersed in 50 mM NaHSO(3) for 10 h, all the RLCs were lowered; chlorophyll fluorescence imaging was inclined to present warmer colors and imaging areas were decreased. However, changes in chloroplast ultrastructures differed from three species. Our results showed that the photosynthetic apparatus of a dominant species, A. acuminatissima, in the late succession stage of a subtropical forest in South China, was less sensitive to NaHSO(3) under both growing light intensities. Conversely, the chloroplasts of P. massoniana, the pioneer heliophyte species, were most susceptible to NaHSO(3). It is deduced that, SO(2) pollution may become as a factor to accelerate the succession of subtropical forest.

Effects of elevated CO2 and N deposition on plant biomass accumulation and allocation in subtropical forest ecosystems: a mesocosm study.

Aims Interactive effects of elevated atmospheric CO2 concentration (CO2) and nitrogen (N) deposition on terrestrial ecosystems play an important role in global carbon cycling. Ecosystems in subtropical and tropical areas occupy a large percent of the global biomass, but few studies have been done in these areas. Therefore, our objective was to conduct an experiment to improve our understand- ing of atmospheric (CO2) enrichment and N deposition effects on biomass accumulation and allocation in subtropical and tropical forests. Methods A model forest ecosystem was constructed of five tree species native to South China: Schima superba, Castanopsis hystrix, Ormosia pinnata, Acmena acuminatissima and Syzygium hancei. The species were exposed to a factorial combination of elevated CO2 and high N deposition in open-top chambers beginning March 2005. There are four experimental treatments, including CN (elevated (CO2) of (700±20) μmol⋅mol -1 and high N of 100 kg N⋅hm -2 ⋅a -1 ), C+ (elevated (CO2) of (700±20) μmol⋅mol -1 and ambient N), N+ (ambient (CO2) and high N of 100 kg N⋅hm -2 ⋅a -1 ) and CK (ambient (CO2) and am-

Effect of Simulated Acid Rain on Potential Carbon and Nitrogen Mineralization in Forest Soils

Acid rain is a serious environmental problem worldwide. In this study, a pot experiment using forest soils planted with the seedlings of four woody species was performed with weekly treatments of pH 4.40, 4.00, 3.52, and 3.05 simulated acid rain (SAR) for 42 months compared to a control of pH 5.00 lake water. The cumulative amounts of C and N mineralization in the five treated soils were determined after incubation at 25 °C for 65 d to examine the effects of SAR treatments. For all five treatments, cumulative CO 2-C production ranged from 20.24 to 27.81 mg kg −1 dry soil, net production of available N from 17.37 to 48.95 mg kg −1 dry soil, and net production of NO −-N from 9.09 to 46.23 mg kg −1 dry soil. SAR treatments generally enhanced the emission of CO 2-C from the soils; however, SAR with pH 3.05 inhibited the emission. SAR treatments decreased the net production of available N and NO3-N. The cumulative CH 4 and N 2O productions from the soils increased with increasing amount of simulated acid rain. The cumulative CO2-C production and the net production of available N of the soil under Acmena acuminatissima were significantly higher (P ≤ 0.05) than those under Schima superba and Cryptocarya concinna. The mineralization of soil organic C was related to the contents of soil organic C and N, but was not related to soil pH. However, the overall effect of acid rain on the storage of soil organic matter and the cycling of important nutrients depended on the amount of acid deposition and the types of forests.

Regulation of Light Energy Utilization and Distribution of Photosynthesis in Five Subtropical Woody Plants

AbstractThe adaptations and responses of photosynthesis to long‐ and short‐term growth light gradient treatments were investigated in five subtropical forest plants, namely Pinus massoniana Lamb., Schima superba Gardn. et Champ., Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., Acmena acuminatissima (BI.) Merr et Perry, and Cryptocarya concinna Hance. With diurnal changes in sunlight and air temperature, the de‐epoxidation state and lutein content in the five woody plants under three light intensities first increased and then decreased during the day. However, maximal photochemical efficiency (Fv/Fm; where Fm is the maximum fluorescence yield and Fv is variable fluorescence) and the photochemical quantum yields of photosystem (PS) II (ΦPSII) of the species examined changed in the opposite manner, with those in plants grown under 100% natural light changing the most. After long‐term treatment (21 months), anti‐oxidant capacity (1, 1‐diphenyl‐2‐picrylhydrazyl radical (DPPH·)‐scavenging capacity) and utilization of excitation energy showed differences in modulation by different light intensities. It was shown that A. acuminatissima and C. concinna, as dominant species in the late succession stage of a subtropical forest in Dinghu mountain, South China, were better able to adapt to different light environments. However, P. massoniana, the pioneer species of this forest, exhibited less adaptation to low light intensity and was definitely eliminated by the forest succession process.

Changes in Photosystem II Activity and Leaf Reflectance Features of Several Subtropical Woody Plants Under Simulated SO2Treatment

The effects of simulated SO2 treatment on the photosynthetic apparatus were investigated in five subtropical forest plants, namely Pinus massoniana Lamb., Schima superba Gardn. et Champ., Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., Acmena acuminatissima (Bl.) Merr et Perry, and Cryptocarya concinna Hance. After leaf sections had been immersed in 0, 20, 50, and 100 mmol/L NaHSO3 for 20 h, total chlorophyll (Chl) content, Chl a/b, maximal photochemical efficiency, and the photochemical quantum yields of photo-system II of all five woody plants were reduced to different degrees, whereas lutein content (Chl base) was increased. Two protective mechanisms, namely the xanthophyll cycle (deepoxidation) and an anti-oxidant system (1,1-diphenyl-2-picrylhydrazyl radical-scavenging capacity), showed differences in the degree of modulation under simulated SO2 treatment. Compared with control (distilled water treatment), the revised normalized difference vegetation index, a leaf reflectance index, was lowered with increasing concentrations of NaHSO3. Cryptocarya concinna, a dominant species in the late succession stage of subtropical forests in South China, exhibited less sensitivity to NaHSO3. Conversely, Pinus massoniana, the pioneer heliophyte species, was most susceptible to NaHSO3 treatment. It is suggested that SO2 pollution may accelerate the succession of subtropical forest. (Managing editor: Ping He)