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The characteristic traits of maize (Zea mays L.) leaves affect light interception and photosynthesis. Measurement or estimation of individual leaf area has been described using discontinuous equations or bell-shaped functions. However, new maize hybrids show different canopy architecture, such as leaf angle in modern maize which is more upright and ear leaf and adjacent leaves which are longer than older hybrids. The original equations and their parameters, which have been used for older maize hybrids and grown at low plant densities, will not accurately represent modern hybrids. Therefore, the aim of this paper was to develop a new empirical equation that captures vertical leaf distribution. To characterize the vertical leaf profile, we conducted a field experiment in Jilin province, Northeast China from 2015 to 2018. Our new equation for the vertical distribution of leaf profile describes leaf length, width or leaf area as a function of leaf rank, using parameters for the maximum value for leaf length, width or area, the leaf rank at which the maximum value is obtained, and the width of the curve. It thus involves one parameter less than the previously used equations. By analysing the characteristics of this new equation, we identified four key leaf ranks (4, 8, 14 and 20) for which leaf parameter values need to be quantified in order to have a good estimation of leaf length, width and area. Together, the method of leaf area estimation proposed here adds versatility for use in modern maize hybrids and simplifies the field measurements by using the four key leaf ranks to estimate vertical leaf distribution in maize canopy instead of all leaf ranks.

Цель статьи – исследование особенностей морфометрических параметров и зольности листовой пластинки наиболее распространенных представителей древесных растений и зольности травянистых растений, произрастающих на территориях Гомельского региона с различным уровнем техногенного влияния, для выявления адаптационной стратегии растений в условиях техногенного воздействия. = The research purpose is the study of leaf plate morphometric parameters and ash-content features of the most widespread representatives of woody plants and grassy plants ash-content growing in Gomel Region territories with technogenic influence of various levels for plants adaptation strategy identification in the technogenic impact conditions.

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<0.0001). However, for certain cultivars, the general equation provided lower precision than the model for each cultivar. Therefore, we conclude that LA can be estimated through the general or individual model for each cultivar., El conocimiento del area foliar (AF) es esencial para evaluar el crecimiento vegetal y estimar el potencial productivo de los cultivos. El objetivo de este trabajo fue desarrollar un modelo predictivo simple, preciso, no destructivo y rápido, para estimar el AF de distintos cultivares de pecan (Carya illinoinensis) en plena producción en Argentina basado en el largo (L) y ancho (A) de los folíolos. Se estudiaron ocho cultivares 'Desirable' 'Harry Super', 'Kernodle', 'Mahan', 'Mahan-Stuart' 'Shoshoni', 'Stuart' y 'Success', injertados sobre un patrón franco de pecan, de 24 años de edad, plantados a 15 x 15 m. Se obtuvo una significativa correlación entre el L o A y el AF de los folíolos. Las mejores correlaciones para cada cultivar se obtuvieron a partir de un análisis discriminante, considerando como variables independientes no forzadas el L y A de cada foliólo. Se propone una ecuación general para el cálculo del AF de todos los cultivares. Sin embargo, para ciertos cultivares la ecuación general permitió un menor ajuste que la presentada para el respectivo cultivar. Se concluye que, según la precisión deseada, puede adoptarse la ecuación general para todos los cultivares o la ecuación particular para cada cultivar.

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<0.0001). However, for certain cultivars, the general equation provided lower precision than the model for each cultivar. Therefore, we conclude that LA can be estimated through the general or individual model for each cultivar., El conocimiento del area foliar (AF) es esencial para evaluar el crecimiento vegetal y estimar el potencial productivo de los cultivos. El objetivo de este trabajo fue desarrollar un modelo predictivo simple, preciso, no destructivo y rápido, para estimar el AF de distintos cultivares de pecan (Carya illinoinensis) en plena producción en Argentina basado en el largo (L) y ancho (A) de los folíolos. Se estudiaron ocho cultivares 'Desirable' 'Harry Super', 'Kernodle', 'Mahan', 'Mahan-Stuart' 'Shoshoni', 'Stuart' y 'Success', injertados sobre un patrón franco de pecan, de 24 años de edad, plantados a 15 x 15 m. Se obtuvo una significativa correlación entre el L o A y el AF de los folíolos. Las mejores correlaciones para cada cultivar se obtuvieron a partir de un análisis discriminante, considerando como variables independientes no forzadas el L y A de cada foliólo. Se propone una ecuación general para el cálculo del AF de todos los cultivares. Sin embargo, para ciertos cultivares la ecuación general permitió un menor ajuste que la presentada para el respectivo cultivar. Se concluye que, según la precisión deseada, puede adoptarse la ecuación general para todos los cultivares o la ecuación particular para cada cultivar.

To increase understanding of the mechanisms involved in leaf-area expansion in the Poaceae, effects of environmental factors on leaf growth of the non-tillering species maize (Zea mays L.) were analysed quantitatively. A growth chamber experiment was carried out with maize cv. Luna including different combinations of temperature (day/night temperatures 13/8, 18/13, 23/18 and 28/23°C) and photosynthetic-photon-flux density (PPFD) (104, 185 and 277 micro mol m-2 s-1). At 13/8°C, a large proportion of the plants died due to prolonged exposure to cold stress. Both high temperatures and high PPFDs increased leaf-appearance rate. Maximum leaf width was highest at intermediate temperatures and high PPFDs, and was strongly related to specific-leaf weight (R²adj=0.88). Leaf-elongation rate increased and leaf-elongation duration decreased with temperature, the resultant being a maximum final leaf length at 23/18°C. Leaf length decreased slightly with PPFD, caused by a shorter leaf-elongation duration. Leaf shape has been described with a new function and was different for Leaves 1 and 2 than for higher-positioned leaves. Leaf width was closely associated with specific leaf weight. The observed relationships can be used in dynamic simulation of leaf area based on plant morphology.

Marine ecosystems are under increasing human pressure and therefore in need of effective management. Marine protected areas (MPAs) can reduce the effects of local disturbances on habitat-forming benthic organisms like corals and seagrasses and are well-known to affect species composition. However, we know considerably less about their effects on organisms’ traits (physiological, morphological, and/or behavioural characteristics), which in turn dictate how organisms respond to stressors and influence ecosystem processes and services. We conducted a field survey along the Kenyan coast to assess the effects of MPAs on species and trait composition of seagrass assemblages; an important group of habitat-forming plants in shallow coastal areas that form the basis for multiple ecosystem services. We measured five morphological traits (shoot density, leaf length and width, number of leaves per shoot, and above:below-ground biomass ratio) on multispecies seagrass assemblages within government MPAs, community MPAs, and fished areas in three habitat zones (shallow, mid-lagoon and, reef). Using causal modelling (path analysis) of multivariate data, we found that MPAs influence seagrass species composition and, indirectly, trait composition in mid-lagoon areas. Meanwhile, there were no MPA effects in the shallow intertidal (potentially because of impacts from MPA-related tourism), and weak effects in the reef zone, presumably due to competition from corals. Finally, most of the MPA effects on overall seagrass trait composition were explained by species turnover, rather than phenotypic plasticity. In conclusion, MPAs appear to be an effective conservation tool for seagrass assemblages by reducing local disturbances and favouring seagrass species with certain traits, primarily in mid-lagoon areas. However, the lack of MPA effect in intertidal areas highlights the need for management approaches that regulate human impacts across the whole tropical coastal zone.