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Phalaenopsis orchids are highly economical ornamental potted plants. Controlling their production schedule requires information on the leaf development characteristics of the orchids. Phalaenopsis leaves affect the plant's photosynthesis, respiration, and transpiration. The leaf growth conditions can serve as a development index for greenhouse management. The use of the growth characteristics of Phalaenopsis leaves as the basis for greenhouse cultivation and management needs to be studied. The allometry of Phalaenopsis leaves is worth studying. The goal of this research was to investigate the allometry of Phalaenopsis leaves and develop prediction models of the total leaf area. Then, these total leaf area models were developed and validated. In this study, five Phalaenopsis varieties (amabilis, Sin-Yuan beauty, Ruey Lish beauty, Ishin KHM1095, and Sogo F1091) were selected. Each sample had five mature leaves. The lengths, widths, and areas of the sequential leaves were measured, and then the length ratios, width ratios, and area ratios were calculated. The top and bottom models were used to calculate the total leaf areas. The results indicate that no significant differences could be found in the length ratios, width ratios, and area ratios of the sequential leaves from the same variety. However, significant differences were found in these leaf characteristics between different varieties. The observation of leaf growth characteristics can be used to provide useful information for Phalaenopsis management. Comparing the predictive criteria of the two models, the top model had a better predictive ability than the bottom model. From a practical viewpoint, measuring the top leaf area is easier than measuring the bottom leaf area in a greenhouse operation. Comparing the effects of the sample numbers on the predictive ability of the model, the sample number of 30 was sufficient to ensure the accuracy of the total leaf area measurements. We provide an easy and accurate method to measure the total leaf area of Phalaenopsis. The calculated values of total leaf areas can be incorporated into decision models for smart management. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Leaf photosynthesis is pivotal for the synthesis of carbohydrates; however, the growth and development of horticultural crops are more closely related to canopy photosynthetic capacity. Measurements of canopy photosynthesis allow a better evaluation of the fruit tree performance at the canopy scale. Therefore, an open chamber system to determine instantaneous canopy apparent photosynthesis (CAPi) was investigated. CAPi slightly overestimated the biomass accumulation by 5.9%, which revealed that the CAPi method is valuable for quantifying canopy photosynthesis. Further, many woody horticultural plants are usually grafted for propagation, such as apples, whereas the rootstocks always influence the canopy size and photosynthesis. In this study, the effect of dwarfing, semi-dwarfing, and vigorous apple rootstocks on canopy photosynthesis was studied. Compared to vigorous rootstock, dwarfing rootstock significantly reduced the leaf net photosynthetic rate and total leaf area by 20.8% and 53.1%, respectively, and resulted in a 59.7% reduction in CAPi. Throughout the study, CAPi was an effective method that should be considered for canopy photosynthesis measurement of horticultural crops in the future. [ABSTRACT FROM AUTHOR]

Phalaenopsis orchids are highly economical ornamental potted plants. Controlling their production schedule requires information on the leaf development characteristics of the orchids. Phalaenopsis leaves affect the plant’s photosynthesis, respiration, and transpiration. The leaf growth conditions can serve as a development index for greenhouse management. The use of the growth characteristics of Phalaenopsis leaves as the basis for greenhouse cultivation and management needs to be studied. The allometry of Phalaenopsis leaves is worth studying. The goal of this research was to investigate the allometry of Phalaenopsis leaves and develop prediction models of the total leaf area. Then, these total leaf area models were developed and validated. In this study, five Phalaenopsis varieties (amabilis, Sin-Yuan beauty, Ruey Lish beauty, Ishin KHM1095, and Sogo F1091) were selected. Each sample had five mature leaves. The lengths, widths, and areas of the sequential leaves were measured, and then the length ratios, width ratios, and area ratios were calculated. The top and bottom models were used to calculate the total leaf areas. The results indicate that no significant differences could be found in the length ratios, width ratios, and area ratios of the sequential leaves from the same variety. However, significant differences were found in these leaf characteristics between different varieties. The observation of leaf growth characteristics can be used to provide useful information for Phalaenopsis management. Comparing the predictive criteria of the two models, the top model had a better predictive ability than the bottom model. From a practical viewpoint, measuring the top leaf area is easier than measuring the bottom leaf area in a greenhouse operation. Comparing the effects of the sample numbers on the predictive ability of the model, the sample number of 30 was sufficient to ensure the accuracy of the total leaf area measurements. We provide an easy and accurate method to measure the total leaf area of Phalaenopsis. The calculated values of total leaf areas can be incorporated into decision models for smart management.

Leaf photosynthesis is pivotal for the synthesis of carbohydrates; however, the growth and development of horticultural crops are more closely related to canopy photosynthetic capacity. Measurements of canopy photosynthesis allow a better evaluation of the fruit tree performance at the canopy scale. Therefore, an open chamber system to determine instantaneous canopy apparent photosynthesis (CAPi) was investigated. CAPi slightly overestimated the biomass accumulation by 5.9%, which revealed that the CAPi method is valuable for quantifying canopy photosynthesis. Further, many woody horticultural plants are usually grafted for propagation, such as apples, whereas the rootstocks always influence the canopy size and photosynthesis. In this study, the effect of dwarfing, semi-dwarfing, and vigorous apple rootstocks on canopy photosynthesis was studied. Compared to vigorous rootstock, dwarfing rootstock significantly reduced the leaf net photosynthetic rate and total leaf area by 20.8% and 53.1%, respectively, and resulted in a 59.7% reduction in CAPi. Throughout the study, CAPi was an effective method that should be considered for canopy photosynthesis measurement of horticultural crops in the future.

As global air pollution, particularly fine particulate matter (PM 2.5), has become a major environmental problem, various PM 2.5 mitigation technologies including green infrastructure have received significant attention. However, owing to spatial constraints on urban greening, there is a lack of management plans for urban forests to efficiently mitigate PM 2.5. In this study, we assessed the PM 2.5 reduction capabilities of Pinus densiflora (Korean red pine) and Quercus acutissima (sawtooth oak) by measuring the changes of PM 2.5 concentrations using an experimental chamber system. In addition, the PM 2.5 reduction efficiency in 90 min (PMRE 90) and the amount of PM 2.5 reduction per leaf area (PMR LA) were compared based on arrangement structures and density levels. The results showed that the PM 2.5 reduction by plants was significantly greater than that of the control experiment without any plants, and an additional reduction effect of approximately 1.38 times was induced by a 1.5 m s−1 air flow. The PMRE 90 of Korean red pine was the highest at medium density. In contrast, the PMRE 90 of sawtooth oak was the highest at high density. The PMR LA of both species was highest at low densities. The different responses of the species to total reduction were well explained by total leaf area (TLA). The PMRE 90 of both species was positively correlated with TLA. The PMR LA of sawtooth oak was approximately 2.3 times greater than that of Korean red pine. However, there were no significant differences in both PMRE 90 and PMR LA between the arrangement structures. Our findings reveal the potential mechanisms of vegetation in reducing PM 2.5 according to arrangement structure and density. This highlights the importance of efficiently using urban green spaces with spatial constraints on PM 2.5 mitigation in the future. [Display omitted] • We quantified PM 2.5 reduction among tree densities and arrangement structures. • The airflow effect further contributed to PM 2.5 reduction. • PM 2.5 reduction by densities showed different responses between the two species. • The total leaf area well explained PM 2.5 reduction efficiency for both species. • The amount of PM 2.5 reduction per leaf area was greater in broad-leaved species. [ABSTRACT FROM AUTHOR]

As global air pollution, particularly fine particulate matter (PM 2.5 ), has become a major environmental problem, various PM 2.5 mitigation technologies including green infrastructure have received significant attention. However, owing to spatial constraints on urban greening, there is a lack of management plans for urban forests to efficiently mitigate PM 2.5 . In this study, we assessed the PM 2.5 reduction capabilities of Pinus densiflora (Korean red pine) and Quercus acutissima (sawtooth oak) by measuring the changes of PM 2.5 concentrations using an experimental chamber system. In addition, the PM 2.5 reduction efficiency in 90 min (PMRE 90 ) and the amount of PM 2.5 reduction per leaf area (PMR LA ) were compared based on arrangement structures and density levels. The results showed that the PM 2.5 reduction by plants was significantly greater than that of the control experiment without any plants, and an additional reduction effect of approximately 1.38 times was induced by a 1.5 m s -1 air flow. The PMRE 90 of Korean red pine was the highest at medium density. In contrast, the PMRE 90 of sawtooth oak was the highest at high density. The PMR LA of both species was highest at low densities. The different responses of the species to total reduction were well explained by total leaf area (TLA). The PMRE 90 of both species was positively correlated with TLA. The PMR LA of sawtooth oak was approximately 2.3 times greater than that of Korean red pine. However, there were no significant differences in both PMRE 90 and PMR LA between the arrangement structures. Our findings reveal the potential mechanisms of vegetation in reducing PM 2.5 according to arrangement structure and density. This highlights the importance of efficiently using urban green spaces with spatial constraints on PM 2.5 mitigation in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Featured Application: Sentinel-2 images were sensitive to change in the vegetation contained in the pixel. The reduction in the NDVI values was proportional to the reduction in the vegetation, following a linear relationship. The quantitative relationship obtained in this study is valuable since a vineyard, once established, generally loses grapevines each year due to diseases, abiotic stress, etc., so it is important to consider the effect of the missing vines in order to have a correct estimation of the vineyard vigour. Remote Sensing (RS) allows the estimation of some important vineyard parameters. There are several platforms for obtaining RS information. In this context, Sentinel satellites are a valuable tool for RS since they provide free and regular images of the earth's surface. However, several problems regarding the low-resolution of the imagery arise when using this technology, such as handling mixed pixels that include vegetation, soil and shadows. Under this condition, the Normalized Difference Vegetation Index (NDVI) value in a particular pixel is an indicator of the amount of vegetation (canopy area) rather than the NDVI from the canopy (as a vigour expression), but its reliability varies depending on several factors, such as the presence of mixed pixels or the effect of missing vines (a vineyard, once established, generally loses grapevines each year due to diseases, abiotic stress, etc.). In this study, a vine removal simulation (greenhouse experiment) and an actual vine removal (field experiment) were carried out. In the field experiment, the position of the Sentinel-2 pixels was marked using high-precision GPS. Controlled removal of vines from a block of cv. Cabernet Sauvignon was done in four steps. The removal of the vines was done during the summer of 2019, matching with the start of the maximum vegetative growth. The Total Leaf Area (TLA) of each pixel was calculated using destructive field measurements. The operations were planned to have two satellite images available between each removal step. As a result, a strong linear relationship (R2 = 0.986 and R2 = 0.72) was obtained between the TLA and NDVI reductions, which quantitatively indicates the effect of the missing vines on the NDVI values. [ABSTRACT FROM AUTHOR]

Copyright of Biological Resources & Nature Management is the property of National University of Life & Environmental Sciences of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Remote Sensing (RS) allows the estimation of some important vineyard parameters. There are several platforms for obtaining RS information. In this context, Sentinel satellites are a valuable tool for RS since they provide free and regular images of the earth’s surface. However, several problems regarding the low-resolution of the imagery arise when using this technology, such as handling mixed pixels that include vegetation, soil and shadows. Under this condition, the Normalized Difference Vegetation Index (NDVI) value in a particular pixel is an indicator of the amount of vegetation (canopy area) rather than the NDVI from the canopy (as a vigour expression), but its reliability varies depending on several factors, such as the presence of mixed pixels or the effect of missing vines (a vineyard, once established, generally loses grapevines each year due to diseases, abiotic stress, etc.). In this study, a vine removal simulation (greenhouse experiment) and an actual vine removal (field experiment) were carried out. In the field experiment, the position of the Sentinel-2 pixels was marked using high-precision GPS. Controlled removal of vines from a block of cv. Cabernet Sauvignon was done in four steps. The removal of the vines was done during the summer of 2019, matching with the start of the maximum vegetative growth. The Total Leaf Area (TLA) of each pixel was calculated using destructive field measurements. The operations were planned to have two satellite images available between each removal step. As a result, a strong linear relationship (R2 = 0.986 and R2 = 0.72) was obtained between the TLA and NDVI reductions, which quantitatively indicates the effect of the missing vines on the NDVI values.

Huanglongbing ( HLB), associated with the phloem-limited bacterium ' Candidatus Liberibacter asiaticus' (Las), is devastating trees in citrus orchards of Florida. Additionally, Phytophthora nicotianae, omnipresent in citrus soils, causes root rot that reduces water and nutrient uptake by fibrous roots. To investigate fibrous root damage and replacement and canopy size in relation to infection of fibrous roots by Las and P. nicotianae, rootstock seedlings of Swingle citrumelo ( Citrus paradisi × Poncirus trifoliata) were inoculated with Las or P. nicotianae in two greenhouse pot trials. Phytophthora nicotianae caused root damage within 5 weeks post-inoculation, which led to greater reduction of canopy size than for Las-infected seedlings by the end of the experiment. Las increased accumulation of fibrous root biomass at 5 weeks post-root trimming (wpt) in the 2014 trial and at 11 wpt in the 2015 trial. New root length was not consistently increased by Las. Reduced total leaf area of symptomless Las-infected seedlings compared to noninoculated controls might be due to the combined effect of altered carbohydrate allocation between shoots and roots and altered leaf morphology. [ABSTRACT FROM AUTHOR]

Aims: In temperate climates, cover crops are mainly used to reduce excess soil water and nutrient availability to grapevines, which otherwise could decrease grape quality. In Mediterranean climates, where water is a limiting factor, the use of cover crops is not as straightforward. However, in this scenario, summer senescent and self-seeding herbaceous cover crops could also help to decrease soil erosion as well as to reduce excessive early vegetative vigour, which could restrict grape water availability at later phenological stages. The aim of this experiment was to study the effects of particular cover crops in Mediterranean vineyards on grapevine vegetative growth, gas exchange, yield and grape quality. Methods and results: The experiment was carried out over three consecutive years in an organic vineyard (cv. Manto Negro) in central Majorca, Spain. Three treatments (three cover cropping rows per treatment) were established: perennial grass and legume mixture (PM), no tillage, i.e., with permanent resident vegetation (NT), and traditional tillage or ploughed soil (TT). The grapevines were rain fed until veraison, and then drip irrigation was applied (30% potential evapotranspiration; ETP) until harvest. Plant water status was established according to a defined value of maximum daily leaf stomatal conductance (gs). Cover crops reduced total leaf area (LA), gs and grapevine vigour at early growth stages. gs and net photosynthesis (AN) were higher in cover crop treatments during the veraison and ripening stages, likely because of the reductions in LA. Intrinsic water use efficiency increased from flowering to veraison-maturity in all treatments. Yield was lower in the cover crop treatments (PM and NT) compared to TT for all years, but these differences were only significant in 2007. However, grape quality parameters slightly improved in the PM treatment. Conclusion: The use of cover crops decreased LA, helping to avoid dramatic reductions of stomatal conductance in mid-summer, but decreased yield and only slightly increased grape quality. Significance and impact of the study: This study showed that the use of specific cover crops in vineyards under Mediterranean climates helps to reduce vegetative vigour. Nevertheless, yield reduction and slight quality improvement suggest that cover crops should be adjusted in order to reduce competition for water and thus prevent these negative effects of water scarcity.

We investigated the flowering probability and flower production in relation to plant size in a terrestrial orchid, Dactylorhiza majalis at 10 meadow sites in central and southwestern Poland. These sites differed in altitude (low, high) and management (presence or absence of mowing). At all sites, concentrations of nutrients in the soil were also measured. The probability of flowering increased significantly with the size of the plant in all populations, indicating that individuals do not flower until they reach a threshold size. Populations at high altitudes and the unmown sites had significantly lower threshold sizes for reproduction and showed sharp increase in flowering probability with plant size, compared to other populations. The threshold sizes for reproduction tended to decrease at sites rich in N and Mg and poor in P and S. Flower production was also size-dependent in all populations. Considerable between-site differences were found in the slope and the intercept of the regression between plant size and flower production. Flower production at some sites, at high altitudes, increased more steeply with plant size than at other sites. However, no pattern in size-dependent flower production was found relative to the measured environmental variables. Most of the size-dependent components of flowering probability were related to each other but not with the size-dependent flower production.

• The total leaf area (TLA) of the canopy was evaluated for variable-rate spraying. • The total grid area (TGA) of the canopy was measured by the first and second echoes of a 2D LiDAR. • The TGA-based TLA evaluation method can adapt to varying point density. In recent years, variable-rate spraying technology has been proposed to solve the pesticide waste and environmental pollution problems caused by traditional spraying methods. Variable-rate spraying methods use sensors to measure the leaf amounts in the target canopies, which are used to adjust the amount of liquid and ensure even spraying for canopies of different sizes and densities. One of these methods uses mobile laser scanning (MLS) technologies with a two-dimensional (2D) light detection and ranging (LiDAR) sensor to capture the point cloud of the canopy, and then the total point number (TPN) is used to evaluate the total leaf area (TLA) of the canopy as a basis for variable-rate spraying. However, the moving speed and ranging distance of LiDAR often vary in the process of spraying, resulting in an inconsistent TPN and a large influence on the accuracy of the TLA measurement. In this paper, a new method for estimating the TLA of an individual tree canopy is proposed based on the total grid area (TGA) measured from the first and second echoes of a LiDAR sensor. The grid area at a single point is calculated by multiplying the LiDAR moving resolution and scanning resolution. To evaluate the proposed method, we use an artificial tree, the branches of which are pruned to generate nine canopies with different densities. Both sides of the canopies are scanned at three distances, namely, 1.0 m, 1.5 m, and 2.0 m, and at a constant moving speed of 0.104 m/s. Then, the point cloud of each canopy is sampled multiple times to simulate a variety of moving speeds ranging from 1.040 m/s to 2.080 m/s. Finally, a total of 594 test canopies are obtained. Univariate polynomial regression is adopted to evaluate the TLA by using the TPN and TGA. When the polynomial order is set to 2, the coefficient of determination (R-squared) of the TPN evaluation is 0.5759 with a 4662.4542 cm2 root mean squared error (RMSE), and the R-squared of the TGA evaluation is 0.9617 with a 1401.1652 cm2 RMSE. The experimental results show that the proposed method can effectively eliminate the effects of different LiDAR moving speeds and ranging distances during TLA measurements. [ABSTRACT FROM AUTHOR]

The effect of minimum tillage on two autochthonousVitis viniferaL. varieties, namely Nerello mascalese and Carricante, established on the eastern and northern aspect slopes of the volcano Mount Etna in Sicily, was evaluated over two seasons. The objective was to determine whether conventional tillage and minimum tillage affect the vegetative growth, bud fertility, total leaf area, leaf nutritional status and fruit yield components. The ratio of bunches/retained buds was strongly influenced by aspect. Yield per vine was significantly different within cultivars and seasons depending on cultivar, tillage treatment and aspect. Due to its natural plasticity in marginal conditions, yields were consistently higher in Nerello mascalese. The yield reduction with minimal tillage was excessive in Carricante. As a consequence of the yield reduction in the second season, total soluble solids in particular were increased in Nerello mascalese. Linear discriminant analysis revealed the highest discrimination values for cultivar and the lowest ones for tillage. [ABSTRACT FROM PUBLISHER]

Understanding scaling relationships between twig size and leaf size along environmental gradients is important for revealing strategies of plant biomass allocation with changing environmental constraints. However, it remains poorly understood how variations in the slope and y -intercept in the twig–leaf size relationship partition among individual, population and species levels across communities. Here, we determined the scaling relationships between twig cross-sectional area (twig size) and total leaf area per twig (leaf size) among individual, population and species levels along a soil moisture gradient in subtropical forests in eastern China. Twig and leaf tissues from 95 woody plant species were collected from three sites that form a soil moisture gradient: a wet site (W), a mesophytic site (M), and a dry site (D). The variance in scaling slope and y -intercept was partitioned among individual, population and species levels using a nested ANOVA. In addition, the change in the twig–leaf size relationship over the soil moisture gradient was determined for each of overlapping and turnover species. Twig size was positively related to leaf size across the three levels, with the variance partitioned at the individual level in scaling slope and y -intercept being 98 and 90%, respectively. Along the soil moisture gradient, the twig–leaf size relationship differed inter- and intraspecifically. At the species and population levels, there were homogeneous slopes but the y -intercept was W > M = D. In contrast, at the individual level, the regression slopes were heterogeneous among the three sites. More remarkably, the twig–leaf size relationships changed from negative allometry for overlapping species to isometry for turnover species. This study provides strong evidence for the twig–leaf size relationship to be intraspecific, particularly at the individual level. Our findings suggest that whether or not species have overlapping habitats is crucial for shaping the deployment pattern between twigs and leaves. [ABSTRACT FROM AUTHOR]

Leaf traits were investigated as morphological attributes for quality estimation of one-year-old bareroot seedlings of Fraxinus angustifolia Vahl. Leaf traits (number of simple - NSL and compound leaves - NCL, leaf average - ALA and total area - TLA and leaf area ratio - LAR) show similar relations to morphological attributes, the strongest to shoot growth (height - HT, root collar diameter - DIA and shoot dry weight - SDW). Increases of seedling morphological attributes are strongly related to increases of ALA. Given to strong positive correlations with other morphological attributes, ALA (R = 0.68-0.88) and TLA (R = 0.46-0.92) are suitable for seedlings quality testing. TLA explained a larger proportion of the variation of SDW (R2 = 0.85) and ALA explained a large proportion of the variation of DIA (R2 = 0.81). Leaf traits can be considered as valuable morphological attributes of seedling quality, in addition to strong correlation with other morphological attributes. [ABSTRACT FROM AUTHOR]

Estimation of total leaf area (LA) is important to express biochemical properties in plant ecology and remote sensing studies. A measurement of LA is easy in broadleaf species, but it remains challenging in coniferous canopies. We proposed a new geometrical model to estimate Norway spruce LA and compared its accuracy with other five published methods. Further, we assessed variability of the total to projected leaf area conversion factor (CF) within a crown and examined its implications for remotely sensed estimates of leaf chlorophyll content ( C). We measured morphological and biochemical properties of three most recent needle age classes in three vertical canopy layers of a 30 and 100-year-old spruce stands. Newly introduced geometrical model and the parallelepiped model predicted spruce LA with an error <5 % of the average needle LA, whereas two models based on an elliptic approximation of a needle shape underestimated LA by up to 60 %. The total to projected leaf area conversion factor varied from 2.5 for shaded to 3.9 for sun exposed needles and remained invariant with needle age class and forest stand age. Erroneous estimation of an average crown CF by 0.2 introduced an error of 2-3 μg cm into the crown averaged C content. In our study, this error represents 10-15 % of observed crown averaged C range (33-53 μg cm). Our results demonstrate the importance of accurate LA estimates for validation of remotely sensed estimates of C content in Norway spruce canopies. [ABSTRACT FROM AUTHOR]

Effects of Quercus ilex acorn size on seedling morphological and physiological traits were analysed. The study was carried out with five populations from different geographical areas and covering an aridity gradient. Seedling morphological traits (height and total leaf area) were analyzed during the first growing year. Physiological traits (net photosynthesis, stomatal conductance, leaf transpiration, and intrinsic water-use efficiency) were analysed at different air temperatures during spring, summer, and winter months, and in response to water stress. There were significant correlations among the considered acorn (volume, fresh mass) and seedling traits. Differences in growth and physiological traits among the considered populations were found. The larger differences in the growth parameters were observed during the first growing season, and they could be justified by the significant differences among acorn size. On the contrary, the physiological response to air temperature and aridity was more related to the geographical origin of the considered populations than to acorn size. Q. ilex acorn and seedling traits more tolerant to drought might have a high potential for vegetation recovery in afforestation projects and restoration programmes particularly under water-limited environments or in degraded areas. [ABSTRACT FROM AUTHOR]

We estimated the magnitude of the total leaf area of the neotropical palm Euterpe oleracea and examined its allometry relative to the variation in stem height and diameter at La Selva Biological Station in Costa Rica. The allometric relationships between frond leaf area and frond length (from tip to base), and between frond leaf area and number of leaflets, were determined by natural logarithmic regressions to estimate the total area of each frond. Palm total leaf area was then estimated by adding the area of the composing fronds. We fit 14 separate regression models that related one or more of the morphological variables (number of fronds, diameter at breast height, stem height) to the total leaf area. Our results show that palm total leaf area is directly proportional to the number of fronds and palm size as reflected in stem height and diameter. Eight out of the 14 models had r values of >0.90 and incorporated a diverse combination of predictor variables. Simple linear regression models were more congruent with the observed values of total leaf area, whereas natural logarithmic models overestimated the value of total leaf area for large palms. Both approaches show a high degree of association among morphological characters in E. oleracea supporting the hypothesis that palms behave like unitary organisms, and are morphologically constrained by the lack of secondary meristems. To afford attaining canopy heights, woody palms need to show a high degree of phenotypic integration, shaping their growth and allometric relationships to match spatial and temporal changes in resources. [ABSTRACT FROM AUTHOR]

A reintroduction experiment of Bidens cernua L., a species included in the Red List of Italian Flora, was carried out at Lake Posta Fibreno (Lazio, central Italy). There were no significant differences in the length of the phenological phases between the reestablished population (Pr) and the natural one (Pn). The length of the phenological cycle, from seedling emergence to the end of the fruiting phase, was 207 ± 3 days. The relative growth rate in height (RGRH) and relative growth rate in mass (RGRm) were significantly (p < 0.05) higher for Pr (0.047 ± 0.001 cm cm-1 d-1 and 0.057 ± 0.001 g g-1 d-1, respectively) than for Pn (0.045 ± 0.001 cm cm-1 d-1 and 0.055 ± 0.001 g g-1 d-1, respectively). There were significant (p < 0.05) differences for plant height (H) and total leaf area per plant (TLA) between Pr and Pn, the latter having the lower values. Total plant dry mass (PDM) was significantly higher for Pr, and the above-ground/below-ground dry mass ratio was 6.7 ± 0.4 and 4.7 ± 0.2 for Pr and Pn, respectively. On the whole, results demonstrate that the Pr of B. cernua has the potential to develop in a manner that is demographically similar to the Pn present in the Posta Fibreno Lake protected area. Abbreviations: H, plant height; LA, mean leaf area; LM, leaf dry mass; PCA, principal component analysis; PDM, total plant dry mass; Pn, natural population; Pr, reestablished population; RGRH, relative growth rate in plant height; RGRm, relative growth rate in plant dry mass; SLA, specific leaf area; TLA, total leaf area per plant [ABSTRACT FROM AUTHOR]

The interactions between salinity and different nitrogen (N) sources nitrate (NO3-), ammonium (NH4+), and NO3- + NH4+ were investigated on Indian mustard (Brassica juncea cv. RH30). Treatments were added to observe the combined effect of two salinity levels (8 and 12 ds m- 1) and three nitrogen sources (NO3-, NH4+, and NO3- + NH4+) on different growth parameters and mineral composition in different plant parts, i.e., leaves, stem, and root. Salinity has been known to affect the uptake and assimilation of various essential nutrients required for normal growth and development. Different growth parameters, i.e., leaf area, dry weight of different plant parts, absolute growth rate (AGR), relative growth rate (RGR), and net assimilation rate (NAR) declined markedly by salinity at pre-flowering and flowering stages. All growth indices were less sensitive to salinity (12 d s m- 1) with the nitrate form of nitrogen. It is pertinent mention that a high dose (120 kg ha- 1) of nitrogen in ammonium form NH4+, acted synergistically with salinity in inhibiting growth. Plants fed with combined nitrogen (NO3- + NH4+) had an edge over individual forms in ameliorating the adverse effects of salinity on growth and yield. Under salt stress, different nutrient elements such as N, phosphorus (P), potassium (K+), and magnesium (Mg2 +) were decreased in different plant parts (leaves, stem, and root). The maximum and minimum reduction was observed with ammoniacal and combined form of nitrogen, respectively, while the reverse was true of calcium (Ca2 +), sodium (Na+), chloride (Cl-), and sulfate (SO42-) at harvest. Nitrogen application (120 Kg ha- 1) in combined form had been found to maintain highest concentrations of N, P, Mg2 +, and Ca2 + along with reduced concentrations of Na+, Cl-, and SO42 -. However, reverse was true with ammoniacal form of nitrogen. [ABSTRACT FROM AUTHOR]

• Irrigation was evaluated on grapevine grown on soil obtained by karst reclamation. • 30–50 % yield reduction was detected in case of unirrigated vines. • Most of the negative effects of temperature stress were mitigated by irrigation. • Deficit irrigation resulted with the balance between grape yield and quality. Stony karst landscape in the Adriatic coastal area has been cultivated for centuries to grow Mediterranean crops. Shallow and less fertile soils were mostly used for rain-fed grapevine and olive production. Native grapevine cultivars are, in general, well adapted to the warm and droughty climate, but a rapid drift in weather patterns characterized mostly by long-lasting high temperature events during the growing season urges the producers to apply irrigation. This research, studying the effects of different irrigation levels on Babić grapevine performance, was carried out in two growing seasons (2015 and 2016) with contrasting weather conditions in a vineyard established on a parcel of land derived from the stony surface of a limestone plateau on the very edge of the Eastern Adriatic coast. The study evaluated the effects of different irrigation regimes based on the quantification of grapevine water use (50, 75, and 100 % of crop evapotranspiration) by measuring the total leaf area, leaf gas exchange performance, and grape yield and quality. The irrigation treatments increased the total leaf area, net photosynthetic rate, average transpiration rate, and average mesophyll CO 2 concentration. The yield components and grape quality were also affected by the irrigation treatments. Positive effects of irrigation in both the experimental seasons were associated with increased yield and total soluble solids (TSS), as well as synchronized TSS and phenolic ripening. Furthermore, water stress positively affected the concentrations of anthocyanins and other polyphenols in both years of the study. In 2015, extremely high temperatures reduced the grape yield, juice yield, and anthocyanin content in grapes in non-irrigated vines as well as in all irrigation treatments. Irrigation was efficient in reducing these negative effects, except in the case of the anthocyanin content. [ABSTRACT FROM AUTHOR]