Is the scaling relationship between carbohydrate storage and leaf biomass in meadow plants affected by the disturbance regime?

BACKGROUND AND AIMS: Below-ground carbohydrate storage is considered an adaptation of plants aimed at regeneration after disturbance. A theoretical model by Iwasa and Kubo was empirically tested which predicted (1) that storage of carbohydrates scales allometrically with leaf biomass and (2) when the disturbance regime is relaxed, the ratio of storage to leaf biomass increases, as carbohydrates are not depleted by disturbance. METHODS: These ideas were tested on nine herbaceous species from a temperate meadow and the disturbance regime was manipulated to create recently abandoned and mown plots. Just before mowing in June and at the end of the season in October, plants with below-ground organs were sampled. The material was used to assess the pool of total non-structural carbohydrates and leaf biomass. KEY RESULTS: In half of the cases, a mostly isometric relationship between below-ground carbohydrate storage and leaf biomass in meadow plants was found. The ratio of below-ground carbohydrate storage to leaf biomass did not change when the disturbance regime was less intensive than that for which the plants were adapted. CONCLUSIONS: These findings (isometric scaling relationship between below-ground carbohydrate storage and leaf biomass; no effect of a relaxed disturbance regime) imply that storage in herbs is probably governed by factors other than just the disturbance regime applied once in a growing season.

A multistressor, multitrait approach to assessing the effects of wind and dust on Eucalyptus tereticornis.

PREMISE OF THE STUDY: Plants are routinely subjected to multiple environmental stressors, and the ability to respond to these stressors determines species survival and ecological breadth. Despite stressors such as wind and dust significantly influencing plant development, morphology, and chemistry, the combined influence of these factors is yet to be investigated. METHODS: We used a manipulative glasshouse approach to compare the morphological, physiological, and biomechanical responses of Eucalyptus tereticornis to the independent and combined effects of wind and dust. KEY RESULTS: Wind decreased both E. tereticornis height and stem flexural stiffness. Additionally, wind had no effect on leaf physiology, nor did dust have any significant effect on any of the traits measured. CONCLUSIONS: Our results suggest that wind and dust in combination may have an additive effect on several plant traits and provide new insight into the effects and importance of studying wind, dust, and different stress combinations.

Diminishing returns: A comparison between fresh mass vs. area and dry mass vs. area in deciduous species.

"Diminishing returns" in leaf economics occurs when increases in lamina mass (M), which can either be represented by lamina dry mass (DM) or fresh mass (FM), fail to produce proportional increases in leaf surface area (A), such that the scaling exponent (α) for the M vs. A scaling relationship exceeds unity (i.e., α > 1.0). Prior studies have shown that FM vs. A is better than DM vs A in assessing diminishing returns in evergreen species. However, the superiority of FM vs. A over DM vs. A has been less well examined for deciduous species. Here, we applied reduced major axis protocols to test whether FM vs. A is better than DM vs. A to describe the M vs. A scaling relationship, using a total of 4271 leaves from ten deciduous and two evergreen tree species in the Fagaceae and Ulmaceae for comparison. The significance of the difference between the scaling exponents of FM vs. A and DM vs. A was tested using the bootstrap percentile method. Further, we tested the non-linearity of the FM (DM) vs. A data on a log-log scale using ordinary least squares. We found that (i) the majority of scaling exponents of FM vs. A and DM vs. A were >1 thereby confirming diminishing returns for all 12 species, (ii) FM vs. A was more robust than DM vs. A to identify the M vs. A scaling relationship, (iii) the non-linearity of the allometric model was significant for both DM vs. A and FM vs. A., and (iv) the evergreen species of Fagaceae had significantly higher DM and FM per unit area than other deciduous species. In summary, FM vs. A is a more reliable measure than DM vs. A when dealing with diminishing returns, and deciduous species tend to invest less biomass in unit leaf light harvesting area than evergreen species.

Nitrogen addition modifies the relative gene expression level and accumulation of carbon-based bioactive substances in Cyclocarya paliurus.

In China, lots of Cyclocarya paliurus plantations have been established for tea and functional food production on nitrogen (N)-limited land. The optimum N levels require for biosynthesis and accumulation of carbon-based bioactive substances vary among plant species. This study integrated field trial with hydroponic culture to assess impact of nitrogen addition on accumulation and relative gene expression level of carbon-based secondary metabolites in C. paliurus. N addition significantly influenced not only contents of polyphenols, flavonoids and triterpenoids and relative gene expression levels of their biosynthetic pathway in C. paliurus leaves but also leaf biomass production and the bioactive substance accumulations. An intermediate N addition induced the highest contents of polyphenols, flavonoids and triterpenoids in leaves, but the optimized accumulation of these bioactive substances in the leaves was the trade-off between their contents and leaf biomass production. Correlation analysis showed that related gene expression levels were closely correlated with contents of their leaf corresponding secondary metabolites. Compared with ratios of carbon/N (C/N) and carbon/phosphorus (C/P) in the soil, ratios of C/N and C/P in the leaves were more strongly related to the contents and accumulations of polyphenols, flavonoids and triterpenoids. To obtain higher yields of targeted phytochemicals, the threshold ratios of C/N and C/P in the leaves are recommended for N and P fertilization at similar sites. Overall, our findings would provide the theoretical basis and technical support for manipulating N fertilization in C. paliurus plantations to obtain higher accumulations of targeted bioactive substances.

Plant traits and environment: floating leaf blade production and turnover of Nymphoides peltata (S.G. Gmel.) O. Kuntze (Menyanthaceae).

Background: Nymphaeid macrophytes, rooting in the sediment of water bodies and characterized by floating leaves, play an important role in wetland ecosystems. The present research deals with the effects of limited space, limited nutrient availability, water temperature and an unexpected inundation on the production, turnover and plasticity of floating leaves of the globally widespread species Nymphoides peltata (Fringed waterlily). Methods: The effects of these environmental conditions were studied in two plots in outdoor concrete tanks (CT1, CT2, mesocosms simulating occurrence in small ponds) and in two plots in the floodplain oxbow lake Bemmelse Strang (BS1, BS2). Plot CT1 was situated in a stand coexisting with helophytes, plot CT2 in a monospecific stand, plot BS1 in the center and plot BS2 at the open water border of a monospecific stand. All floating leaf blades within the plots were marked at appearance at the water surface and subsequently length, width and damage of each leaf and maximum and minimum water temperatures were measured bi-weekly. Area and biomass of leaf blades were calculated based on leaf length and width and were used to calculate turnover rates and production. Results: The growth period started in May and ended mid-October with continuous production of floating leaves during nearly the whole vegetation period. In the tanks the water level was very stable, but the lake underwent an inundation by river water, causing a sudden loss of existing leaves. Considering environmental conditions and based on the assumed ranking from low to high nutrient availability, the ranking of the plots was CT1, CT2, BS1, BS2. This order was found for maximum leaf life span and maximum leaf length, and the reverse order was found for number of leaves, new leaves per day and duration of the vegetation period. Turnover rates appeared to be relatively similar for plots CT1, CT2 and BS1, but for the deeper border plot BS2 lower ratios were found. These results indicate that increased enclosure with expected nutrient limitation causes (1) the production of high numbers of small leaves with larger totals for leaf area and biomass, (2) a shift towards increased sexual reproduction by the production of more flowering stem leaves.

Effects of biotic and abiotic factors on forest biomass fractions.

The extent to which key factors at the global scale influence plant biomass allocation patterns remains unclear. Here, we provide a theory about how biotic and abiotic factors influence plant biomass allocation and evaluate its predictions using a large global database for forested communities. Our analyses confirm theoretical predictions that temperature, precipitation, and plant height and density jointly regulate the quotient of leaf biomass and total biomass, and that they have a much weaker effect on shoot (leaf plus stem) biomass fractions at a global scale. Moreover, biotic factors have larger effects than abiotic factors. Climatic variables act equally on shoot and root growth, and differences in plant body size and age, as well as community species composition, which vary with climate in ways that drown out the variations in biomass fractions. The theory and data presented here provide mechanistic explanations of why climate has little effect on biomass fractions.

Potential of Mulberry Leaf Biomass and Its Flavonoids to Improve Production and Health in Ruminants: Mechanistic Insights and Prospects.

Leaf biomass from the mulberry plant (genus Morus and family Moraceae) is considered a potential resource for livestock feeding. Mulberry leaves (MLs) contain high protein (14.0-34.2%) and metabolizable energy (1130-2240 kcal/kg) with high dry matter (DM) digestibility (75-85%) and palatability. Flavonoid contents of MLs confer unique antioxidant properties and can potentially help alleviate oxidative stress in animals during stressful periods, such as neonatal, weaning, and periparturient periods. In addition, mulberry leaf flavonoids (MLFs) possess antimicrobial properties and can effectively decrease the population of ruminal methanogens and protozoa to reduce enteric methane (CH4) production. Owing to its rich flavonoid content, feeding MLs increases fiber digestion and utilization leading to enhanced milk production in ruminants. Dietary supplementation with MLFs alters ruminal fermentation kinetics by increasing total volatile fatty acids, propionate, and ammonia concentrations. Furthermore, they can substantially increase the population of specific cellulolytic bacteria in the rumen. Owing to their structural homology with steroid hormones, the MLFs can potentially modulate different metabolic pathways particularly those linked with energy homeostasis. This review aims to highlight the potential of ML and its flavonoids to modulate the ruminal microbiome, fermentation, and metabolic status to enhance productive performance and health in ruminants while reducing CH4 emission.

[Effects of the current-year shoot stem configuration on leaf biomass in different canopy heights of woody plants in evergreen broad-leaved forest in Jiangxi Province, China.] / æ±Ÿè¥¿å¸¸ç»¿é˜”å¶æž—æœ¨æœ¬æ¤ç‰©ä¸åŒå† å±‚é«˜åº¦å½“å¹´ç”Ÿå°æžèŒŽæž„åž‹å¯¹å¶ç”Ÿç‰©é‡çš„å½±å“.

To investigate the effects of stem configuration on leaf biomass allocation in different organs of the current-year shoots at different canopy heights, relationships of biomass in different organs (i.e., leaves, stems, and twigs) and stem configuration (i.e., stem diameter, length, width/length, stem volume and stem density) were analyzed using the data of 69 woody species from the Yangjifeng Natural Reserve, Jiangxi Provence. Standardized major axis (SMA) was used to explore the regression between biomass and stem configuration. The results showed that there was no significant difference in leaf biomass, stem biomass, twig biomass, stem diameter, stem length, stem width/length and stem volume of current year shoots from upper and lower canopy heights and life forms (i.e., evergreen and deciduous woody plants). Stem density differed significantly in the current year shoots at different heights for both evergreen and deciduous woody species. There were isometric relationships among leaf, stem and total biomass of shoots in different canopy heights and in different life forms. Leaf biomass scaled allometrically with stem diameter and volume, with the scaling exponents being not different significantly among different canopy heights. With respect to the stem configuration of the twigs, stem length, stem width/length and stem density contributed less than 24% to the leaf biomass variation in the current-year shoots. On the contrary, stem diameter and volume had greater effects on leaf biomass of the current-year shoots than stem length, stem width/length and stem density. Canopy heights did not significantly affect the allometric scaling relationships between the stem configuration and leaf biomass of the current-year shoots.

Light quality affects flavonoid production and related gene expression in Cyclocarya paliurus.

Understanding the responses of plant growth and secondary metabolites to differential light conditions is very important to optimize cultivation conditions of medicinal woody plants. As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. In this study, LED-based light including white light (WL), blue light (BL), red light (RL), and green light (GL) were used to affect leaf biomass production, flavonoid accumulation and related gene expression of one-year C. paliurus seedlings in controlled environments. After the treatments of 60 days, the highest leaf biomass appeared in the treatment of WL, while the lowest leaf biomass was found under GL. Compared to WL, the total flavonoid contents of C. paliurus leaves were significantly higher in BL, RL, and GL, but the highest values of selected flavonoids (kaempferol, isoquercitrin and quercetin) were observed under BL. Furthermore, the greatest yields of total and selected flavonoids in C. paliurus leaves per seedling were also achieved under BL, indicating that blue light was effective for inducing the production of flavonoids in C. paliurus leaves. Pearson's correlation analysis showed that there were significantly positive correlations between leaf flavonoid content and relative gene expression of key enzymes (phenylalanine ammonia lyase, PAL; 4-coumaroyl CoA-ligase, 4CL; and chalcone synthase, CHS) in the upstream, which converting phenylalanine into the flavonoid skeleton of tetrahydroxy chalcone. It is concluded that manipulating light quality may be potential mean to achieve the highest yields of flavonoids in C. paliurus cultivation, however this needs to be further verified by more field trials.

Hyperspectral Estimation of Canopy Leaf Biomass Phenotype per Ground Area Using a Continuous Wavelet Analysis in Wheat.

To extend agricultural productivity by knowledge-based breeding and tailoring varieties to adapt to specific environmental conditions, it is imperative to improve our ability to acquire the dynamic changes of the crop's phenotype under field conditions. Canopy leaf biomass (CLB) per ground area is one of the key crop phenotypic parameters in plant breeding. The most promising technique for effectively monitoring CLB is the hyperspectral vegetation index (VI). However, VI-based empirical models are limited by their poor stability and extrapolation difficulties when used to assess complex dynamic environments with different varieties, growth stages, and sites. It has been proven difficult to calibrate and validate some VI-based models. To address this problem, eight field experiments using eight wheat varieties were conducted during the period of 2003-2011 at four sites, and continuous wavelet transform (CWT) was applied to estimate CLB from large number of field experimental data. The analysis of 108 wavelet functions from all 15 wavelet families revealed that the best wavelet features for CLB in terms of wavelength (W) and scale (S) were observed in the near-infrared region and at high scales (7 and 8). The best wavelet-based model was derived from the Daubechies family (db), and was named db7 (W1197 nm, S8). The new model was more accurate ( R v 2 = 0.67 and RRMSE = 27.26%) than a model obtained using the best existing VI ( R v 2 = 0.54 and RRMSE = 34.71%). Furthermore, the stable performance of the optimal db7 wavelet feature was confirmed by its limited variation among the different varieties, growth stages, and sites, which confirmed the high stability of the CWT to estimate CLB with hyperspectral data. This study highlighted the potential of precision phenotyping to assess the dynamic genetics of complex traits, especially those not amenable to traditional phenotyping.

Is leaf area of Norway spruce (Picea abies L. Karst.) and European larch (Larix decidua Mill.) affected by mixture proportion and stand density?

KEY MESSAGE: Trees with otherwise equal dimensions have different leaf areas if they are located in different stand types. While leaf area of European larch is affected by mixture proportion, leaf area of Norway spruce is affected by stand density. CONTEXT: Leaf area is a key parameter for evaluating growth efficiency of trees, and therefore needs to be measured as consistently and accurately as possible. This is even more important when comparing monospecific and mixed stands. AIMS: The aim of the study is to find combinations of parameters and allometric relationships that can be used to estimate accurately the leaf area of individual trees. METHODS: Allometries of the measured leaf area of 194 trees in 12 stands were analysed in order to find variables affecting leaf area. Existing functions from the literature were validated. Finally, models were fitted to find the most appropriate method for estimating leaf area of mixed and monospecific stands of Norway spruce and European larch. RESULTS: Allometric relationships of leaf area to other measurable characteristics of trees vary in different stand types. Besides individual tree dimensions such as diameter and crown surface area, leaf area of Norway spruce is related to stand density, whereas the leaf area of European larch is dependent on the admixture of Norway spruce in the stand. CONCLUSION: In contrast to models for estimating individual tree leaf area of Norway spruce, models for leaf area of European larch have to consider mixture proportions in order to correctly interpret the growth efficiency of mixed stands.

Effect of light regime and provenance on leaf characteristics, growth and flavonoid accumulation in Cyclocarya paliurus (Batal) Iljinskaja coppices.

BACKGROUND: As a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. However, limited information is available on its genotype selection and cultivation for growth and phytochemicals. Responses of growth and secondary metabolites to light regimes and genotypes are useful information to determine suitable habitat conditions for the cultivation of medicinal plants. RESULTS: Both light regime and provenance significantly affected the leaf characteristics, leaf flavonoid contents, biomass production and flavonoid accumulation per plant. Leaf thickness, length of palisade cells and chlorophyll a/b decreased significantly under shading conditions, while leaf areas and total chlorophyll content increased obviously. In the full light condition, leaf flavonoid contents showed a bimodal temporal variation pattern with the maximum observed in August and the second peak in October, while shading treatment not only reduced the leaf content of flavonoids but also delayed the peak appearing of the flavonoid contents in the leaves of C. paliurus. Strong correlations were found between leaf thickness, palisade length, monthly light intensity and measured flavonoid contents in the leaves of C. paliurus. Muchuan provenance with full light achieved the highest leaf biomass and flavonoid accumulation per plant. CONCLUSIONS: Cyclocarya paliurus genotypes show diverse responses to different light regimes in leaf characteristics, biomass production and flavonoid accumulation, highlighting the opportunity for extensive selection in the leaf flavonoid production.

Biomass components and structure of massai grass fertilized with nitrogen and grazed by sheep / Componentes da biomassa e estrutura do capim-massai adubado com nitrogênio e pastejado por ovinos

To evaluate the biomass components of massai grass subjected to nitrogen (N) fertilization levels (control - 0; 400; 800 and 1200 kg ha-1 year-1 of N) and under rotational stocking with sheep, this study was undertaken using a completely randomized design with measurements repeated in time. A quadratic response was observed reaching maximum values as the levels of nitrogen fertilization increased for green forage biomass, green leaf biomass, green stem biomass (5,172.9; 4,146.3; 1,033.9 kg ha-1 cycle-1, respectively), forage total density (179.1 kg ha-1 cm-1), canopy height (36.8 cm) and live material/dead material ratio (4.0) at levels 896; 934; 797; 879.2; 751.4 and 1,161 kg ha-1 year-1 of N, respectively. For all variables, oscillation was observed between the grazing cycles studied. Nitrogen fertilization has a positive response on the biomass components and canopy structure of massai grass.(AU)

Objetivou-se avaliar os componentes da biomassa do capim-massai sob lotação rotativa com ovinos e adubado com doses de nitrogênio (controle - 0; 400; 800 e 1200 kg de N ha -1 ano -1 ), em delineamento inteiramente ao acaso, com medidas repetidas no tempo. Constatou-se resposta quadrática, alcançando valores máximos com o incremento das doses de nitrogênio para as produções de biomassa de forragem verde, de lâmina foliar verde, de colmo verde (5172,9; 4146,3; 1033,9 kg ha -1 ciclo -1 , respectivamente) e para a densidade total de forragem (179,1 kg ha -1 cm -1 ), altura do dossel (36,8 cm) e relação material vivo/material morto (4,0) nas doses 896; 934; 797; 879,2; 751,4 e 1161 kg ha -1 ano -1 de N, respectivamente. Para todas as variáveis, verificou-se oscilação entre os ciclos de pastejo estudados. A adubação nitrogenada exerce respostas positivas sobre os componentes da biomassa e a estrutura do dossel do capim-massai.(AU)

Spatio-temporal variation of biogenic volatile organic compounds emissions in China.

Aiming to reduce the large uncertainties of biogenic volatile organic compounds (BVOCs) emissions estimation, the emission inventory of BVOCs in China at a high spatial and temporal resolution of 36 km × 36 km and 1 h was established using MEGANv2.1 with MM5 providing high-resolution meteorological data, based on the most detailed and latest vegetation investigations. BVOC emissions from 82 plant functional types in China were computed firstly. More local species-specific emission rates were developed combining statistical analysis and category classification, and the leaf biomass was estimated based on vegetation volume and production with biomass-apportion models. The total annual BVOC emissions in 2003 were 42.5 Tg, including isoprene 23.4 Tg, monoterpene 5.6 Tg, sesquiterpene 1.0 Tg, and other VOCs (OVOCs) 12.5 Tg. Subtropical and tropical evergreen and deciduous broadleaf shrubs, Quercus, and bamboo contributed more than 45% to the total BVOC emissions. The highest biogenic emissions were found over northeastern, southeastern, and southwestern China. Strong seasonal pattern was observed with the highest BVOC emissions in July and the lowest in January and December, with daily emission peaked at approximately 13:00 or 14:00 local time.

Genotypic value in hybrid progenies of Panicum maximum Jacq / Valor genotípico de progênies híbridas de Panicum maximum Jacq

ABSTRACT: Genetic breeding of forage plants has increasingly contributed to the release of more productive plants. In this regard, evaluating the genotypic value is essential when aiming to rank genotypes based on the mean free of environmental factors. Therefore, this study aimed to predict the genotypic value of agronomic and nutritive value characters of three progenies of Panicum maximum. Hybrids were evaluated in a clonal test in an incomplete-randomized design with three treatments (progenies 1, 2, and 3) and two replications (clones). Six harvests were performed at 25cm from the ground level throughout one year. Progeny 2 provided better results for total and leaf dry mass yield, regrowth, and height, and lower incidence of leaf spot. Progenies 1 and 3 had a better response for qualitative characters such as higher crude protein and digestibility and lower lignin and fiber content. Hybrid progenies of P. maximum have forage characters of interest for breeding, and when using 'Mombaça' grass as parents, the progeny stands out for leaf production and resistance to leaf spot and for 'Tanzania' grass as parent has resulted in better forage quality.

RESUMO: O lançamento de forrageiras resultantes de programas de melhoramento genético tem sido importante fonte de liberação de novas forrageiras mais adaptadas e competitivas. Nessas situações, a avaliação do valor genético é essencial quando se objetiva ranquear os genótipos com base no valor genotípico, isento dos efeitos ambientais. O objetivo com este trabalho foi estimar e avaliar o valor genotípico de características agronômicas e de valor nutritivo de três progênies de P. maximum, resultantes do cruzamento entre duas progenitoras sexuais e as cultivares 'Mombaça' e 'Tanzânia'. O experimento foi implantado em teste clonal no delineamento em blocos incompletos com três tratamentos (progênies 1, 2 e 3) com duas repetições (clones). Os híbridos foram manejados por meio de cortes na altura de 25cm do nível do solo por um ano, realizando seis cortes. A progênie 2 proporcionou melhores resultados para produção de folhas, rebrota, altura de planta e baixa incidência de mancha foliar causada por Bipolaris maydis. As progênies 1 e 3 apresentaram, em média, melhores resultados para características qualitativas como proteína bruta e digestibilidade e menor teor de lignina. As progênies híbridas de P. maximum apresentam características forrageiras de interesse para o melhoramento, sendo que a utilização do capim-mombaça como parental proporciona maior produção de folhas e resistência à mancha foliar, ao passo que o capim-tanzânia como parental proporciona melhoria da qualidade da forragem.

Variabilidad ambiental y respuestas fisiológicas de Polylepis cuadrijuga (Rosaceae) en un ambiente fragmentado en el Páramo de la Rusia (Colombia) / Environmental variability and physiological responses from Polylepis cuadrijuga (Rosaceae) in a fragmented environment in the Páramo de la Rusia (Colombia)

Polylepis cuadrijuga is an endemic woody species from the Colombian Eastern range, being the only tree species with capacity to live on mountainous environments beyond 4 000m of altitude. Grazing and agriculture have transformed at least 30% of the Guantiva-La Rusia region, turning continuous extensions of high Andean forest in a fragmented landscape, and P. cuadrijuga remnants have become smaller and more isolated. The aim of this study was to establish the environmental differences between a matrix of grazing pastures and the interior of fragments, to evaluate the physiological responses of P. cuadrijuga and determining the edge effect. Air temperature and humidity, soil water holding capacity and photosynthetic active radiation, were measured along two 50X2m transects from the matrix toward the center of fragment. Six trees inside the transects were chosen in each one of three sites (matrix, edge and interior) to measure the index chlorophyll content and to sample leaves to assess the leaf area, leaf biomass, specific leaf area, anatomy, health condition and pubescence. Results showed significantly differences between the matrix and the interior and intermediate conditions in the edge. Radiation, temperature and air desiccation were higher in the matrix than in the interior, submitting P. cuadrijuga trees to a stressing environment, where they presented stratification of epidermis and palisade parenchyma, and a higher leaf area, leaf thickness, chlorophyll content and pubescence than in the interior of fragments. All these physiological traits allow avoiding the photoxidation and damages by freezing or desiccation to which trees are exposed in a grazing pasture matrix. Nevertheless, there was a higher frequency of healthy leaves in the interior of fragments, showing that high irradiations and extreme air temperature and humidity reach adversely affect to P. cuadrijuga. Individuals in the edge had ecophysiological traits similar to the matrix ones, which confirm an edge effect that could penetrate 17m inside the fragments. We conclude that P. cuadrijuga is a plastic species, able to overcome the stress conditions from anthropogenic transformations, species able to be used in high Andean forest restoration programs.

Polylepis cuadrijuga es una especie leñosa endémica de la cordillera oriental de Colombia, donde la agricultura y el pastoreo han generado la fragmentación de sus bosques. Para determinar si existe un efecto borde en fragmentos ubicados en el Páramo de la Rusia, se establecieron diferencias ambientales y se evaluó las respuestas ecofisiológicas de P. cuadrijuga entre matriz de pastura, borde e interior de los fragmentos, a través de la medición de temperatura ambiental, humedad relativa, capacidad de retención de agua del suelo y radiación fotosintéticamente activa, a lo largo de dos transectos de 50m desde la matriz hacia el interior. En cada sitio se escogieron seis árboles para evaluar el contenido de clorofila, área foliar, biomasa foliar, área foliar específica, anatomía foliar, sanidad y pubescencia. En matriz fue mayor la temperatura y la radiación, condiciones relacionadas con la disminución del AFE y el aumento del contenido de clorofilas, evidenciado por la presencia de un parénquima en empalizada biestratificado. Características ecofisiológicas similares a las expuestas en borde, confirman un efecto de borde que podría penetra unos 17m en el interior de los fragmentos. Se concluye que P. cuadrijuga es una especie plástica, capaz de enfrentar condiciones de estrés generadas por actividades antropogénicas.

Rapid multiplication and in vitro production of leaf biomass in Kaempferia galanga through tissue culture

An efficient protocol has been established for rapid multiplication and in vitro production of leaf biomass in Kaempferia galanga L, a rare medicinal plant. Different plant growth regulators like Benzyladenine (BA), Indoleacetic acid (IAA), Indolebutyric acid (IBA), Napthaleneacetic acid (NAA) and adenine sulphates (Ads) have been tried for induction of multiple shoots using lateral bud of rhizome as explants. The highest rate of shoot multiplication (11.5 +/- 0.6) shoot/explant as well as leaf biomass production (7.4 +/- 0.3) gram/explant was observed on Murashige and Skoog medium supplemented with Benzyladenine (1 mg/l) and Indoleacetic acid (0.5 mg/l). Data of shoot multiplication and leaf biomass production were statistically analysed. Upon excission of leaves after 2 months of culture under sterile condition, the base of each plantlet was transferred to fresh media which could produce the same leaf biomass within another 2 months in a 50 ml culture tube containing 20 ml and 250 ml conical flasks containing 30 ml Murashige and Skoog medium. The rate of multiplication and leaf biomass production remained unchanged in subsequent subcultures. The regenerated plantlets were acclimatized in greenhouse and subsequently transferred to the field. Survival rate of the plantlets under ex vitro condition was 95 percent. Genetic fidelity of the regenerants was confirmed using random amplified polymorphic DNA (RAPD) marker. The protocol could be commercially utilized for large scale production of true-to-type plantlets and as an alternative method of leaf biomass production in Kaempferia galanga.