Herbivory and leaf expansion of Cyathea phalerata Mart. (Cyatheaceae) in subtropical Atlantic Forest, southern Brazil

Herbivory is an interaction with great impact on plant communities since relationships between herbivores and plants are fundamental to the distribution and abundance of species over time and space. The aim of this study was to monitor the rate of leaf expansion in the tree fern Cyathea phalerata and evaluate the damage caused by herbivores to leaves of different ages and whether such damage is related to temperature and precipitation. The study was performed in a subtropical Atlantic Forest fragment located in the municipality of Caraá, in the northeast hillside of Rio Grande do Sul state, in southern Brazil. We monitored 24 mature individuals of C. phalerata with croziers in a population of approximately 50 plants. Leaf expansion rate, percentage of damaged leaves and leaf blade consumption rate by herbivory were calculated. Monthly means for temperature and accumulated rainfall were calculated from daily data. Croziers of C. phalerata were found to expand rapidly during the first and second months after emergence (3.98 cm day-1; 2.91 cm day-1, respectively). Damage caused by herbivory was observed in all of the monitored leaves, but none of the plants experienced complete defoliation. The highest percentage (57%) of damaged leaves was recorded at 60 days of monitoring, and also the highest monthly consumption rate of the blade (6.04%) occurred with young, newly-expanded leaves, while this rate remained between 1.50 and 2.21% for mature leaves. Rates of monthly leaf consumption and damaged leaves showed positive and strong relationship with each other and with temperature. The rapid leaf expansion observed for C. phalerata can be considered a phenological strategy to reduce damage to young leaves by shortening the developmental period and accelerating the increase of defenses in mature leaves.

Diversity of culturable endophytic fungi vary through time in Manihot esculenta Crantz

Endophytic fungi are a ubiquituos group that colonize all plant species on earth. Studies comparing the location of endophytic fungi within the leaves and the sampling time in Manihot esculenta Crantz (cassava) are limited. In this study, mature leaves of M. esculenta from Panama were collected in order to compare the cultivable diversity of endophytic fungi and to determine their distribution within the leaves. A total of one hundred sixty endophytes belonging to 97 species representing 13 genera and 8 morphospecies determined as mycelia sterilia that containing 63 isolates were isolated. Cladosporium, Nigrospora, Periconia, and mycelia sterilia 1 and 3 were the most predominant isolated endophytes. We detected that endophytes varied across the sampling time, but not amongst locations within leaves. The endophytes composition across sampling and the location of endophytes within leaf was similar, except for Periconia and mycelia sterilia 3 and 7. The data generated in this study contribute to the knowledge on the biodiversity of endophytic fungi in Panama, and establish the bases for future research focused on understanding the function of endophytes in M. esculenta crops.

Anatomical adjustment of mature leaves of sycamore maple (Acer pseudoplatanus L.) to increased irradiance

Trees regenerating in the understory respond to increased availability of light caused by gap formation by undergoing a range of morphological and physiological adjustments. These adjustments include the production of thick, sun-type leaves containing thicker mesophyll and longer palisade cells than in shade-type leaves. We asked whether in the shade-regenerating tree Acer pseudoplatanus, the increase in leaf thickness and expansion of leaf tissues are possible also in leaves that had been fully formed prior to the increase in irradiance, a response reported so far only for a handful of species. We acclimated potted seedlings to eight levels (from 1 to 100%) of solar irradiance and, in late summer, transferred a subset of them to full sunlight. Within 30 days, the shaded leaves increased leaf mass per area and became thicker mostly due to elongation of palisade cells, except for the most shaded individuals which suffered irreversible photo-oxidative damage. This anatomical acclimation was accompanied by partial degradation of chlorophyll and a transient decline in photosynthetic efficiency of PSII (Fv/FM). These effects were related to the degree of pre-shading. The Fv/FM recovered substantially within the re-acclimation period. However, leaves of transferred plants were shed significantly earlier in the fall, indicating that the acclimation was not fully effective. These results show that A. pseudoplatanus is one of the few known species in which mature leaves may re-acclimate anatomically to increased irradiance. This may be a potentially important mechanism enhancing utilization of gaps created during the growing season.

Regulation of Leaf Angle Protects Photosystem I under Fluctuating Light in Tobacco Young Leaves

Fluctuating light is a typical light condition in nature and can cause selective photodamage to photosystem I (PSI). The sensitivity of PSI to fluctuating light is influenced by the amplitude of low/high light intensity. Tobacco mature leaves are tended to be horizontal to maximize the light absorption and photosynthesis, but young leaves are usually vertical to diminish the light absorption. Therefore, we tested the hypothesis that such regulation of the leaf angle in young leaves might protect PSI against photoinhibition under fluctuating light. We found that, upon a sudden increase in illumination, PSI was over-reduced in extreme young leaves but was oxidized in mature leaves. After fluctuating light treatment, such PSI over-reduction aggravated PSI photoinhibition in young leaves. Furthermore, the leaf angle was tightly correlated to the extent of PSI photoinhibition induced by fluctuating light. Therefore, vertical young leaves are more susceptible to PSI photoinhibition than horizontal mature leaves when exposed to the same fluctuating light. In young leaves, the vertical leaf angle decreased the light absorption and thus lowered the amplitude of low/high light intensity. Therefore, the regulation of the leaf angle was found for the first time as an important strategy used by young leaves to protect PSI against photoinhibition under fluctuating light. To our knowledge, we show here new insight into the photoprotection for PSI under fluctuating light in nature.

Review on Ethnobotany and Phytopharmacology on Mesua ferrea Linn

This work was performed to study the ethnobotany and phytopharmacological properties of M. ferrea L. It is widely distributed in the tropical areas of the world, especially in the Asian countries and is traditionally used by the local peoples for curing diseases ranging from head ache to cancer. Mesua ferrea is cultivated as an ornamental plant and young leaves are reddish yellow in color while mature leaves are blue grey to dark green in appearance with fragrant white flowers. This study reveals that almost all part of the plant have high medicinal property against different ailments. M. ferrea Linn being used for its anticancer, antineoplastic, disinfectant, anti oxidant, hepato-protective, anti arthritic, diuretic, analgesic etc. properties. The phytochemical screening confirms the presence of phenyl coumarins, xanthones, triterpenoids, tannin and saponin as main constituents responsible for its biological activity. It is also used in the cosmetics. This can be used as remedial agents for various health issues. This review reveals the phyto-pharmacological role of this medicinal plant.

The Evolution of Leaf Function during Development Is Reflected in Profound Changes in the Metabolic Composition of the Vacuole

During its development, the leaf undergoes profound metabolic changes to ensure, among other things, its growth. The subcellular metabolome of tomato leaves was studied at four stages of leaf development, with a particular emphasis on the composition of the vacuole, a major actor of cell growth. For this, leaves were collected at different positions of the plant, corresponding to different developmental stages. Coupling cytology approaches to non-aqueous cell fractionation allowed to estimate the subcellular concentrations of major compounds in the leaves. The results showed major changes in the composition of the vacuole across leaf development. Thus, sucrose underwent a strong allocation, being mostly located in the vacuole at the beginning of development and in the cytosol at maturity. Furthermore, these analyses revealed that the vacuole, rather rich in secondary metabolites and sugars in the growth phases, accumulated organic acids thereafter. This result suggests that the maintenance of the osmolarity of the vacuole of mature leaves would largely involve inorganic molecules.

Thermo Condition Determines the Uptake of Autumn and Winter Applied Nitrogen and Subsequent Utilization in Spring Tea (Camellia sinensis L.)

The effect of thermal condition on the uptake of autumn and winter applied N and its subsequent utilization in spring tea (Camellia sinensis) was investigated by applying 15N enriched urea as single or split applications between October and February in two commercial plantations at Xingyang of Henan province and Yongchuan of Chongqing with different thermal conditions. The proportion of N derived from 15N-labeled urea (Ndff%) in fibrous root and mature leaves 15 days after application at Xingyang and the Ndff% of mature leaves on the day of the first spring tea harvest at both sites were the highest in the single October application. The Ndff% of the following spring tea was also the highest in the single October application at both sites. The results showed that application of N fertilizer in October relative to other later months most significantly improves the accumulation of plant N reserves and consequently contributes more significantly to the early spring tea. Such timing effect was related to the thermal condition, i.e., the growing degree days (°C•d, T > 8 °C) between the dates of fertilization and harvest of young shoots, which represents the combining effect of the temperature and the residence time of N fertilizer in the soil.

Oviposition Preferences of Oriental Fruit Moth Grapholita Molesta (Lepidoptera: Tortricidae) To Pear HIPVs

Herbivore-induced plant volatiles (HIPVs) are regarded as an indirect plant defense against herbivores, since they attract natural enemies to the infested plant. On the other hand, HIPVs also affect behavioral responses of herbivores. In a previous study, Lytopylus rufipes, a parasitoid of the oriental fruit moth (Grapholita molesta), showed positive responses to pear HIPVs, but the influence of pear HIPVs on G. molesta is still unclear. To better understand these responses, we first tested oviposition preferences of G. molesta to uninfested and infested pear shoots (US and IS, respectively) and uninfested mature leaves (ML) in dual-choice bioassays with a cylindrical tube. Then, preferences to volatile components were also assessed. Results show that G. molesta females preferred US-, IS-, and ML-treated areas compared to the control area (no leaves), respectively. Subsequently, G. molesta females preferred IS over US, and US more than ML when comparing pear tissues. Furthermore, G. molesta females didn’t show any significant preference to individual volatile components, but more eggs were laid in the area treated with a synthetic pear HIPV blend, compared to the hexane-treated area (control). These results indicate that G. molesta females do not avoid infested pear shoots nor HIPVs. Moreover, HIPVs may recruit not only natural enemies, but herbivores to the release point of HIPVs. Thus, it is important to examine the responses of G. molesta females to HIPVs in the field before employing them for pest management.

Accumulation of Amino Acids and Flavonoids in Young Tea Shoots Is Highly Correlated With Carbon and Nitrogen Metabolism in Roots and Mature Leaves

The quality of tea product and the metabolism of quality-related compounds in young shoots are significantly affected by the nitrogen(N) supply. However, little is known of the metabolic changes that take place in tea roots and mature leaves under different supplies, which has a large effect on the accumulation of quality-related compounds in young shoots. In this study, young shoots, mature leaves, and roots under different N conditions were subjected to metabolite profiling using gas chromatography and ultraperformance liquid chromatography, coupled with quadrupole time-of-flight mass spectrometry. The contents of free amino acids (e.g., theanine and glutamate) involved in N metabolism were significantly greater under high N than under low N, while a high N supply reduced soluble sugars (e.g., glucose) in all three tissues. Organic acids (e.g., malate, fumarate, α-ketoglutatare, and succinate) involved in tricarboxylic acid cycle remarkably increased as the nitrogen supply increased, which confirms that carbon (C) allocation was restricted by increasing the nitrogen supply, especially in mature leaves. RT-PCR results indicated that gene expression related to nitrogen assimilation significantly increased in roots with increasing nitrogen supply, which had a significant positive relationship with the level of free amino acids in young shoots. In addition, the expression of most genes involved in flavonoid synthesis was significantly upregulated under conditions of low nitrogen supply relative to high nitrogen supply in young shoot and roots. These data suggest that enhanced assimilation of N in tea roots and the coordinated regulation of C (sugars, organic acids, and flavonoids) and N(amino acids) in mature leaves can lead to a high accumulation of amino acids in young shoots. Furthermore, as the N supply increased, more C was partitioned into compounds containing N in mature leaves and roots, resulting in a decrease in flavonoids in young shoots. In conclusion, the accumulation of amino acids and flavonoids in young tea shoots is highly correlated with carbon and nitrogen metabolism in roots and mature leaves.

Food selection by the northern yellow-cheeked crested gibbons (Nomascus annamensis), northern Cambodia

<p>Tropical regions have extremely high plant diversity, which in turn supports a high diversity of animals. However, not all plant species are selected by animals as food sources, with some herbivores selecting only specific plants as food as not all plants have the same nutrient make up. Animals must select which food items to include in their diets, as the amount and type of nutrients in their diet can affect lifespan, health, fitness, and reproduction. Gibbon populations have declined significantly in recent years due to habitat destruction and hunting. Northern yellow-cheeked crested gibbon (Nomascus annamensis) is a newly described species, and has a limited distribution restricted to Cambodia, Laos and Vietnam. The northern yellow-cheeked crested gibbons play an important role in seed dispersal, yet little is currently known about this species, including its food selection and nutritional needs. However, data on food selection and nutritional composition of selected food items would greatly inform the conservation of both wild and captive populations of this species. This study aims to quantify food selection by the northern yellow-cheeked crested gibbons by investigating the main plant species consumed and the influence of the availability of food items on their selection. The study also explores the nutritional composition of food items consumed by this gibbon species and identifying key plant species that provide these significant nutrients. A habituated group of the northern yellow-cheeked crested gibbons with five members located in northern Cambodia was studied for 12 weeks during the dry season, and focal animal sampling was used to observe individual feeding behaviours. Four main activity categories were recorded including resting, feeding, travelling and socializing. Phenological data was recorded from transect lines, and plant densities from 20 vegetation plots inside the home range of this group of gibbons were also measured. Seventy-four plant samples from 20 tree and liana species that were consumed by this group of gibbons were collected for nutritional analyses. These samples were initially dried in sunlight, and then oven dried before levels of protein, total non-structural carbohydrates, lipids, fibres and condensed tannins were measured at the Nutritional Ecology Lab at Hunter College of the City University of New York, New York. The northern yellow-cheeked crested gibbon individuals spent most of the time resting, followed by feeding, travelling and socializing. Their main diet was fruit, supplemented with young leaves, flowers, mature leaves, and occasionally insects. Individuals selected food from 37 plant species, but predominately fed on just 16 of these species. The three most-consumed species were fruit from Ilex umbellulata (tree), Ficus. sp (liana), and young leaves from Lithocarpus elegans (tree). There was a significant relationship between feeding time and the availability of flowers, indicating that flowers were actively selected for when present. However, there was no significant relationship between feeding time and the availability of fruit or young leaves. Only a small number of plants bore fruit, with very low densities in the home range of this gibbon study group, but these plants produced a large abundance of fruit. These findings clearly indicate that fruit is the main diet for northern yellow-cheeked crested gibbons in the dry season, with young leaves, flowers, mature leaves and insects acting as secondary food sources. The northern yellow-cheeked crested gibbons selected only a small number of specific plants in their territory for food sources, indicating that any selective logging targeting these plant species would reduce food availability, and restrict the diet of these animals. Fruits consumed by the northern yellow-cheeked crested gibbons were rich in carbohydrates and lipids, while young leaves were richest concentration of protein. Mature leaves had a high moisture content, whereas flowers contained condensed tannins more often than other plant tissues. All plant tissues consumed had similar amount of fibres. Generally, the food items consumed had higher concentrations of carbohydrate than protein or lipids. The overall diet of this group of gibbons was low in lipids. These results indicate that northern yellow-cheeked crested gibbon consumed food items with high concentrations of carbohydrate, and only selected a few food sources with high level of protein. Overall, these findings have contributed important knowledge that can be used for long-term conservation of this gibbon species. There are a small number of key food species in the home range which need special protection. The northern yellow-cheeked crested gibbons consumed food items from different plant species, and as a consequence, all plant species selected play an important role for nutritional requirements by this gibbon species. When considering feeding requirement by the northern yellow-cheeked crested gibbons for captive breeding programs, diets should include fruit, which is rich in carbohydrates, and young leaves, which have high levels of protein.</p>