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Se estudió el efecto de la edad y largo foliar en la calidad de láminas de agropiro alargado (Thinopyrum ponticum cv. Hulk) en un rebrote otoñal de dos alturas. El ensayo se realizó en invernáculo (17± 4 ºC) en un diseño BCA (n=3) de 160 macetas por bloque. Se estudiaron láminas de 3 generaciones sucesivas de hojas en 6 estados ontogénicos (de crecimiento hasta senescencia avanzada). Las láminas se obtuvieron de ~200 macollos vegetativos/cosecha, muestreados a lo largo de 52 días de rebrote, con una frecuencia de 80 GDC (grados día de crecimiento: Σ t1/2- 4,5 ºC). Se midió la vida media foliar (VMF), el intervalo de aparición (IAH), largo de lámina y vaina, contenido de FDN y digestibilidad in vitro de la FDN (DFDN). Se realizaron ajustes lineales entre variables de calidad con edad y largo de hoja y se compararon pendientes y ordenadas al origen (PROC REG de SAS). El resto de las variables se analizaron según BCA con arreglo factorial (2 alturas x 3 generaciones de hoja) utilizando el procedimiento GLM de SAS. Las medias se compararon por el test de Tukey al 5%. La pastura de menor altura (241,8 vs 458,4 mm) tuvo mayor VMF (453,6 vs 337,8 GDC), similar contenido de FDN (52,3%) y mayor DFDN (~10%). En ambas pasturas la DFDN disminuyó linealmente con la edad y el largo foliar, pero la FDN no fue afectada durante la VMF. Se concluye que durante el rebrote la DFDN disminuye con la edad y el aumento del largo foliar entre hojas sucesivas y que la reducción de la altura de la pastura retrasa la senescencia (>VMF), aumenta el número de hojas vivas por macollo y la calidad de las láminas.

Modelling leaf shape is a helpful tool for designing optimal plant shape and visualizing plant growth. The objectives of this study were to characterize the changes in patterns of leaf growth characteristics during plant development, and to model the changes in morphology of the different leaves of the rice (Oryza sativa L.) plant. In four experiments, time course observations were made on length and width of the leaves on the main stem and tillers of rice plants grown under different experimental conditions. Three experiments provided the data for developing a model. The results show that the expansion process of a single leaf on the main stem and tillers against growing degree days (GDD) followed a slow–rapid–slow pattern that was described well by a logistic function. The changes in final length of the regular leaves positioned on the main stem were described by a quadratic function that differed from the function for the flag leaf. Final leaf length on the tillers followed the ratio of the length of the simultaneously expanding leaves on the tiller to the length of the corresponding leaves on the main stem. The changes in leaf width with leaf length in relation to GDD for a single leaf on the main stem and tillers were described by a quadratic function. The general relationships between final leaf length and final leaf width for the first fully expanded leaves and the flag leaves on the main stem and tillers were described by exponential functions, whereas for the other leaves quadratic functions were needed. The effects of nitrogen level and water regime on leaf growth were quantified by using leaf-nitrogen and leaf-water contents. The model, which was validated with the independent data from the fourth experiment, predicted the time course morphological changes of leaves on the main stem and tillers of rice grown with different nitrogen and water levels well. The results of this study can lead to a more accurate description of the rice leaf in a 3D space by integrating the model with the morphogenesis models of sheath, internode and panicle within the framework of plant topology. In addition, the present leaf architecture model may be combined with a leaf emergence model and a leaf curvature model for digital representation of light interception and utilization within the leaf canopy of rice.

In the Mediterranean region Cymodocea nodosa is widely distributed throughout shallow sites. Therefore, a correct assessment of the status of its meadows is of great importance for the implementation of the Water Framework Directive (WFD), the Marine Strategy Framework Directive (MSFD), and the Habitat Directive (HD), especially for areas where Posidonia oceanica meadows (the most frequently used indicator in the Mediterranean Sea) are rare or not present. The previously proposed index for the evaluation of the status of C. nodosa meadows (CymoSkew) is based on ln-transformed relative frequencies of photosynthetic leaf lengths, which we believe is statistically questionable. Therefore, we further improved the methodology and developed a new index named MediSkew, where ln-transformation is applied to raw data of leaf lengths. More specifically, the index is a combination of two metrics, both based on C. nodosa leaf length: deviation from the reference median length (Medi-) and skewness of the length frequency distribution (-Skew), though greater importance was assigned to the first. To develop the classification criteria for the assessment of the status, also a Pressure Index for Seagrass Meadows (PISM), for the evaluation of pressureeimpact relationships, was developed. The MediSkew is meant to be a rapid screening method for wide areas, therefore the index should be tested for the assessment of the status of C. nodosa meadows throughout Mediterranean coastal waters.

In grasses, leaf growth is often monitored to gain insights in growth processes, biomass accumulation, regrowth after cutting, etc. To study the growth dynamics of the grass leaf, its length is measured at regular time intervals to derive the leaf elongation rate (LER) profile over time. From the LER profile, parameters such as maximal LER and leaf elongation duration (LED), which are essential for detecting inter-genotype growth differences and/or quantifying plant growth responses to changing environmental conditions, can be determined. As growth is influenced by the circadian clock and, especially in grasses, changes in environmental conditions such as temperature and evaporative demand, the LER profiles show considerable experimental variation and thus often do not follow a smooth curve. Hence it is difficult to quantify the duration and timing of growth. For these reasons, the measured data points should be fitted using a suitable mathematical function, such as the beta sigmoid function for leaf elongation. In the context of high-throughput phenotyping, we implemented the fitting of leaf growth measurements into a user-friendly Microsoft Excel-based macro, a tool called LEAF-E. LEAF-E allows to perform non-linear regression modeling of leaf length measurements suitable for robust and automated extraction of leaf growth parameters such as LER and LED from large datasets. LEAF-E is particularly useful to quantify the timing of leaf growth, which forms an important added value for detecting differences in leaf growth development. We illustrate the broad application range of LEAF-E using published and unpublished data sets of maize, Miscanthus spp. and Brachypodium distachyon, generated in independent experiments and for different purposes. In addition, we show that LEAF-E could also be used to fit datasets of other growth-related processes that follow the sigmoidal profile, such as cell length measurements along the leaf axis. Given its user-friendliness, ability to quantify duration and timing of leaf growth and broad application range, LEAF-E is a tool that could be routinely used to study growth processes following the sigmoidal profile. Electronic supplementary material The online version of this article (doi:10.1186/1746-4811-10-37) contains supplementary material, which is available to authorized users.

Seeds and seedlings of soft wheat (Triticum vulgare Vill.) were used to study seed germination, leaf elongation, and the content of photosynthetic pigments (chlorophylls a, b and carotenoids) as affected by five concentrations of iron-containing nanoparticles (NP): spherical Fe0 NP with the diameter of 80 знак плюс минус 5 nm and the magnetite Fe3O4 NP measuring 50-80 nm in width and 4-10 nm in height.

Leaf area (LA) is a valuable key for evaluating plant growth, therefore accurate, simple, and nondestructive methods for LA determination are important for physiological and agronomic studies. A LA prediction model based on leaf length (L) and width (W) and developed under greenhouse on 14 cultivars of rose (Rosa hybr.*) was validated on a different cultivar of R. hybrida ’Red France’ and on a wild rose species (Rosa sempervirens L.) grown under open-field conditions with two light environments: ambient and 50% shade. Comparisons between measured vs. calculated LA using the following model: LA (cm²) = 0.56 + 0.717 LW, showed a high degree of correlation (R² > 0.95) and provided quantitative evidence of the validity of the LA prediction model. Calculated LA values were very close to the measured values, giving an underestimation of 3.5%, 4.2%, 1.1%, and an overestimation of 1.3% in the prediction for R. hybrida ambient light, R. hybrida 50% shade, R. sempervirens ambient light, R. sempervirens 50% shade, respectively. This model can provide accurate estimations of rose LA independently of the genetic materials and the growing conditions and can be adopted in many experimental comparisons without the use of any expensive instruments.

(2004). Comparison of Leaf Photosynthesis between Wild and Cultivated Types of Soybean. Plant Production Science: Vol. 7, No. 3, pp. 277-279.

Objetivou-se avaliar as características morfogênicas e estruturais do pasto de Brachiaria decumbens, submetido a intensidades, frequências de corte e adubação nitrogenada. O delineamento experimental foi em blocos casualizados em esquema de parcelas subdivididas, tendo na parcela o arranjo fatorial 2 x 2 referente a combinações entre duas alturas de corte (40 e 50 cm) e duas alturas de resíduo (15 e 25 cm) e nas sub-parcelas a adubação nitrogenada (com ou sem nitrogênio), com quatro repetições. As variáveis analisadas para as características morfogênicas foram: taxa de alongamento foliar (TAlF); taxa de alongamento de colmo (TAlC); taxa de aparecimento foliar (TApF); taxa de senescência foliar (TSF) e filocrono; e para as características estruturais foram: número de perfilhos basais (NPB); número de folhas totais (NFT); número de folhas aparecidas (NFAp); número de folhas mortas (NFM); número de folhas vivas (NFV) e comprimento final da folha (CFF). A utilização de 100 kg/ha de N permitiu aumento (p

Com o objetivo de avaliar a influência de doses e épocas de aplicação de nitrogênio após o corte no fator de correção de área foliar, na taxa de alongamento de folhas e no comprimento e área da lâmina foliar do capim-bermuda tifton 85 (Cynodon spp) foram conduzidos dois experimentos em casa de vegetação. Ambos os experimentos foram estabelecidos em vasos com capacidade para 7 kg de terra, com solo classificado como Neossolo Quartzarênico Órtico típico, em esquema fatorial 4 × 2, para avaliação de quatro doses de nitrogênio (0, 80, 160 e 240 mg kg-1 de solo) e duas épocas de aplicação (imediatamente após o corte e sete dias após o corte das plantas). O delineamento experimental foi em blocos completos ao acaso, com quatro repetições. Com o fornecimento de nitrogênio, observou-se diminuição no fator de correção de área foliar. O nitrogênio proporciona variação positiva no comprimento foliar, na área da lâmina foliar e na taxa de alongamento da folha, variações que ocorreram em maior grandeza entre a não-aplicação de nitrogênio e a dose de 80 mg kg-1 de solo. With the objective of evaluating the influence of nitrogen rates and application time after cutting on correction factor for leaf area, on leaf elongation rate and on blade leaf length and area of tifton 85 bermudagrass (Cynodon spp), two experiments were carried out in a greenhouse. Both experiments were established in pots with capacity for 7 kg of soil classified as Entisol, in a 4 × 2 factorial scheme, for evaluation of four nitrogen rates (0, 80, 160 and 240 mg kg-1 of soil) and two application times (immediately after cutting and seven days after cutting of the plants). It was used a complete randomized block design, with four replications. As nitrogen was supplied, it was observed a decrease in the correction factor for leaf area. There is a predominance of positive effects of nitrogen on leaf length, on leaf blade area and on leaf elongation rate. Great nitrogen effect was observed when comparying no-nitrogen application with the rate of 80 mg kg-1 of soil.

WOS: 000277016300007 The study was aimed to modeling of the individual leaf area and dry weight of oregano ( origanum onites L.) using leaf length, leaf width and SPAD value. Non-destructive approach of modeling can be very useful for plant growth estimation. To predict individual leaf area and dry weight of oregano, models were developed using leaf length, leaf width, SPAD value, and different combinations of these variables. Eight regression equations, commonly used for developing growth models, were compared for accuracy and adaptability. The two nonlinear models developed were as follows: individual leaf area LA = 0.104 + 0.363W + 0.380L(2) - 0.028W(2) (R(2) = 0.973) and dry weight DW = 0.0018 + 0.00102WS + 3.45E(-4) LWS (R(2) = 0.928), where L is the leaf length, W the leaf width, S the SPAD value, and LWS = L x W x S. For validation of the model, estimated values for individual leaf area and dry weight showed strong agreement with the measured values, respectively. Leaf dry weight, especially, was estimated with a higher degree of accuracy through the use of a SPAD value, as well as leaf length and width. Therefore, it is concluded that models presented herein may be useful for the estimation of the individual leaf area and dry weight of oregano with a high degree of accuracy.

In a sward, the quantity and quality of light are modified by the canopy, with in particular a decrease of red – far red ratio and a decrease of blue light. Plants react to these modifications by altering their shoot morphogenesis. In particular, in grasses, modification of light composition induces leaf growth changes. The objective of this study was to evaluate the effect of light quality and quantity on leaf growth in a set of perennial ryegrass genotypes. Ten clones of ten perennial genotypes highly variable in leaf length were used. Four light treatments were applied: a standard treatment (transparent filter), decreased PAR (neutral filter decreasing all the wavelengths similarly), low red – far red ratio associated with low blue (green filter, simulating the effect of a canopy), and low blue (red filter). After a growing period of three weeks, plants were defoliated and the light treatments were applied. Leaves three and four following defoliation were measured in order to obtain leaf elongation rate (LER), leaf elongation duration (LED) and adult leaf length. Strong genotype and light effects were observed on all traits. The low blue treatment had a particularly large effect, increasing adult leaf length by increasing both LER and LED. The differences in adult leaf length between genotypes were explained by both LER and LED. The genotypic × treatment interaction was significant but low in comparison to the principal effects.

S.L Torri , C. Descalzi, and E. Frusso. 2009. Estimation of leaf area in pecan cultivars (Carya illinoinensis). Cien. Inv. Agr. 36(1): 53-58. Nondestructive and mathematical approaches of modeling can be very convenient and useful for plant growth estimation. The objective of this research was to develop a simple, accurate and nondestructive predictive model for leaf area (LA) estimation in different pecan cultivars (Carya illinoinensis) commonly found in Argentina. Linear and exponential regression equations were fitted and evaluated for pecan cultivars 'Desirable', 'Harry Super', 'Kernodle', 'Mahan', 'Mahan-Stuart', 'Shoshoni', 'Stuart' and 'Success' (grafted on seedling pecan rootstocks, 24 years old, planted at 15 x 15 m) using length (L) and width (W) alternatively or both L and W in a stepwise analysis as non-forced independent variables. Stepwise regression analysis using L and W variables for each cultivar fitted the data better than L or W alone. A general equation for all cultivars showed high accuracy (R² = 0.93, p

International audience; In an agroforestry context, the knowledge of leaf area is an important parameter to take into consideration because tree foliage shades the intercrop. Single leaf measurement (for example leaf length and width) is a widely used method to estimate leaf area in a rapid non-destructive way. In this study, the objectives were to estimate the leaf area of different leaf sizes and shapes for Acacia mangium Willd. (Mimosaceae), Tectona grandis L. (Verbenaceae), Hevea brasiliensis Muell.-Arg. (Euphorbiaceae), and Swietenia macrophylla King. (Meliaceae) Indonesian agroforestry trees. In order to characterise leaf area in field conditions a digital photograph method was used. Leaf length was measured in order to build relationships between leaf length versus actual leaf area. Additional measurements obtained from the digital pictures such as lamina width, number of leaflets, leaflet length and width were recorded in order to test the benefit regarding leaf area estimation based only on the leaf length model. The combination of these different linear leaf measurements led to various degrees of precision of leaf area estimation. The different models can then be chosen according to a compromise between the accuracy of leaf area estimation and the time allocated to field measurements.

Leaf area measurement can be a time consuming process and requires sophisticated electronic instruments. The objective of this research was to develop a simple, accurate, non-destructive and time saving predictive model for leaf area (LA) estimation in sweet cherry trees. Linear regression equations were fitted and evaluated for three cultivars and two training systems using alternatively the length (L), the width (W) and their product (L*W) as independent variables. Regression using L*W variable fitted the data better (R2 = 0.994) than L or W (R2 = 0.863 and 0.787, respectively). The slopes using L*W as the explanatory variable were between 0.6776 and 0.6442 for different combinations of cultivar and training system. Combinations of cultivar training system showed different slopes (P

Bromus setifolius Presl., a native perennial grass, is widely spread in the harsh environment of Patagonia, Argentina. This grass can be associated with Neotyphodium Glenn, Bacon et Hanlin endophytes which are related to aerial tissues of these plants and never show external signs of infection. Endophyte presence of certain grasses improves abiotic and biotic stress resistance, productivity or reproduction in their hosts. To compare and contrast natural populations of B. setifolius differing in endophyte infection diaspore weight of seven populations was registered. In addition, emergence and growth parameters of seedlings, dry weight, leaf length and mortality rate were measured. For this purpose, two independents assays were conducted under controlled environmental conditions, using an infected (E+) and an uninfected (E–) population in each one. Most of the analysed parameters differed between E+ and E– populations, being significantly greater in E+ populations. Populations with percentage of endophyte infection between 0% and 100% presented intermediate mean diaspore weight. These results could suggest an adaptive advantage of infected plants as a consequence of endophyte presence. Fil: Novas, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentina Fil: Gentile, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentina Fil: Cabral, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; Argentina

Se estudiaron las variaciones en el área, la longitud y la relación entre longitud y ancho máximo de las hojas de Nothofagus pumilio a lo largo de los brotes y entre brotes de diferente tamaño. En tres poblaciones se registraron tendencias semejantes en cuanto al tamaño y la forma de las láminas a lo largo de brotes de tamaño similar. En los brotes cortos, de tres nomofilos, el tamaño de la lámina se incrementó desde el nomofilo más proximal hasta el más distal. En brotes con mayor número de hojas, el tamaño de la lámina aumentó desde la hoja más proximal a la hoja en posición 4 ó 5 y tendió a disminuir desde ésta hacia hojas más distales. Los brotes cortos, que se desarrollan hacia el centro de la copa del árbol (presumiblemente más sombreado), tienden a presentar láminas más pequeñas que los brotes de mayor tamaño, cuya posición en el árbol es más periférica (y menos sombreada). Dado el reducido tamaño de las hojas más distales de los brotes de tamaño intermedio y largo, la capacidad de aprovechamiento fotosintético del espacio alcanzado por esos brotes sería, en el corto plazo, limitada. Variations in the area, length and length/width ratio of Nothofagus pumilio leaves along shoots and among shoots of different size were studied. For three populations of trees, similar tendencies in leaf size and form were found for shoots of similar size. In short shoots, those with three green leaves, the size of the lamina tended to increase from the proximal to the distal leaf. In shoots with more leaves, the size of the lamina increased from the most proximal leaf to the fourth or fifth leaf and decreased from these leaves to the most distal ones. Short shoots, which were found close to the centre of the crown (in presumably more shaded conditions) tended to have smaller leaves than longer shoots, which developed in more peripheral (and less shaded) placements. Since distal leaves of shoots of intermediate and large length tend to be relatively small, the capacity of these shoots to take photosynthetic advantage of their size would be limited in the short term.

Populus euramericana (Dode) Guinier cv. Robusta plants were cultivated at irradiances of 7.5, 15 and 30 W m−2 (32.5, 65 and 130 μmol m2 s−1), 400–700 nm at 22°C and a relative humidity between 40 and 60% on a gravel culture subirrigated with Hoagland's nutrient solution. The basal diameter of the growing shoot, a measure of the number of apical cells participating in growth, increased proportionally to irradiance and was correlated with mature leaf length. The development of the length of the growing shoot (Lgs) depended also on the nutritional status of the (young) shoot. Lgs was strongly correlated with the rate of height growth.