New plant trait records of the Hungarian flora

Canopy height, leaf area (LA), specific leaf area (SLA) and leaf dry matter content (LDMC) data of 210 species of the Hungarian flora resulting from our field sampling are presented in this data paper

Foliar and wood traits covary along a vertical gradient within the crown of long-lived light-demanding species of the Congo Basin semi-deciduous forest

Plant functional traits have shown to be relevant predictors of forest functional responses to climate change. However, the trait-based approach to study plant performances and ecological strategies has mostly been focused on trait comparisons at the interspecific and intraspecific levels. In this study, we analyzed traits variation and association at the individual level. We measured wood and leaf traits at different height locations within the crown of five individuals of Pericopsis data (Harms) Meeuwen (Fabaceae) from the northern tropical forest of the Democratic Republic of the Congo. All traits varied between and within individuals. The between-individual variation was more important for leaf traits (23%-48%) than for wood traits (similar to 10%) where the within-individual variation showed to be more important (33%-39%). The sample location height within the crown was found to be the driving factor of this within-individual variation. In a gradient from the base to the top of the crown, theoretical specific hydraulic conductivity and specific leaf area decreased while the stomatal density increased. We found significant relationships among traits and between wood and leaf traits. However, these relationships varied with the position within the crown. The relationship between vessel size and vessel density was negative at the bottom part of the crown but positive upward. Also, the negative relationship between stomatal density and stomatal size became stronger with increasing height within the crown. Finally, the positive relationship between specific leaf area and theoretical specific hydraulic conductivity became stronger in higher parts of the crown, suggesting that P. data constantly adapts its water use with respect to its water supply, more strongly at the top of the crown where the environment is more extreme and less buffered against environmental fluctuations

Lianas Suppress Seedling Growth and Survival of 14 Tree Species in a Panamanian Tropical Forest

Lianas are a common plant growth form in tropical forests, where they compete intensely with trees, decreasing tree recruitment, growth, and survival. If the detrimental effects of lianas vary significantly with tree species identity, as is often assumed, then lianas may influence tree species diversity and community composition. Furthermore, recent studies have shown that liana abundance and biomass are increasing relative to trees in neotropical forests, which will likely magnify the detrimental effects of lianas and may ultimately alter tree species diversity, relative abundances, and community composition. Few studies, however, have tested the responses of multiple tree species to the presence of lianas in robust, well‐replicated experiments. We tested the hypotheses that lianas reduce tree seedling growth and survival, and that the effect of lianas varies with tree species identity. We used a large‐scale liana removal experiment in Central Panama in which we planted 14 replicate seedlings of 14 different tree species that varied in shade tolerance in each of 16 80 × 80 m plots (eight liana‐removal and eight unmanipulated controls; 3136 total seedlings). Over a nearly two‐yr period, we found that tree seedlings survived 75% more, grew 300% taller, and had twice the aboveground biomass in liana‐removal plots than seedlings in control plots, consistent with strong competition between lianas and tree seedlings. There were no significant differences in the response of tree species to liana competition (i.e., there was no species by treatment interaction), indicating that lianas had a similar negative effect on all 14 tree species. Furthermore, the effect of lianas did not vary with tree species shade tolerance classification, suggesting that the liana effect was not solely based on light. Based on these findings, recently observed increases in liana abundance in neotropical forests will substantially reduce tree regeneration, but will not significantly alter tropical tree species diversity, relative abundance, or community composition

Plant analysis as a tool to determine crop nitrogen status

An effective plant nutrient management strategy optimises nitrogen (N) use efficiency for minimised environmental impact, while ensuring an optimum N status of the crop for good product quality and maximum growth. Soil or plant analysis can be used to evaluate the strategy; however the use of plant analysis for this purpose has been limited. One reason is lack of reliable reference values for the critical concentration needed for optimal growth. This study builds on theories that relate ontogenetic changes in the critical N concentration to changes in the relation between mass and surface area of the entire plant and of individual leaves. Through the establishment of critical N concentrations on the basis of these theories, some of the drawbacks hitherto experienced with plant analysis, such as difficulties in defining growth stage or plant part to sample, can be avoided. The aim of this thesis was to establish critical N concentrations for white cabbage (Brassica oleracea L. var. capitata L. f. alba D.C.) on the basis of these theories. Multi-N-rate and multi-harvest experiments were conducted in the field and in a climate chamber. The results showed that the critical N concentration declined at the same rate (-0.33) as the plant's leaf area ratio (leaf area divided by plant mass), which is in agreement with the 2/3-Power rule or "skin-core" hypothesis. The critical N concentration (% of DM) on a whole plant basis was estimated to 4.5 (W1.5 t ha-1), where W is weight per unit area of plant dry matter exclusive of roots. Moreover, it was concluded that the unshaded horizontally orientated leaves of cabbage can be used for leaf area based plant analysis of individual leaves. The critical N concentration of these leaves expressed on an area basis was found to be 3.7 g N m-2, while that for the whole plant N on a leaf area basis was 4.7 g N m-2. The ratio of these two critical concentrations, 0.8, was similar to the leaf N ratio (leaf N/whole plant N) of young plants before self shading occurs

Leaf biomass and leaf area equations for three planted trees in Iran

Leaf area (LA) and leaf biomass (LB) are important variables for most physiological, horticultural and agronomic studies involving plant growth, development rate, radiation use efficiency, and water or nutrient use. Measuring these variables need destructive and aggressive sampling. Fortunately, evolving allometric equations can help for low cost and non-destructive estimation of such variables. The aims of this study are Estimate, compare and develop allometric models of LA and LB per tree and per stand for Alnus subcordata (AS), Populus deltoides (PD) and Taxodium distichum (TD) plantations. We selected 12 sample trees in each stand. Leaf Fresh weight of randomly selected branches was weighted in the field. Branch-level LA was modeled as a function of branch diameter (R2 > 0.8) and total fresh weight of LB has been calculated for each sampled tree. For each species, 100 leaves from all canopy directions of trees were randomly selected and transported to the laboratory. At the lab, leaf area has been measured using leaf area meter. Allometric equations were derived using regression analysis. For all species, derived equations showed high accuracy (R2 ranged from 0.837 to 0.947). However, with respect to mean square error, power regression equations (individual leaf area = a(L×W)b and LA or LB = a DBHb) are best models to estimate Individual Leaf Area, LA, and LB of AS, PD, and PD. The highest LAI was in the order of 16.9 > 5.5 > 4.5 for AS, PD, and TD, respectively. DOI: http://dx.doi.org/10.5281/zenodo.26791

Changes in oak (Quercus robur) photosynthesis after winter moth (Operophtera brumata) herbivory are not explained by changes in chemical or structural leaf traits

Insect herbivores have the potential to change both physical and chemical traits of their host plant. Although the impacts of herbivores on their hosts have been widely studied, experiments assessing changes in multiple leaf traits or functions simultaneously are still rare. We experimentally tested whether herbivory by winter moth (Operophtera brumata) caterpillars and mechanical leaf wounding changed leaf mass per area, leaf area, leaf carbon and nitrogen content, and the concentrations of 27 polyphenol compounds on oak (Quercus robur) leaves. To investigate how potential changes in the studied traits affect leaf functioning, we related the traits to the rates of leaf photosynthesis and respiration. Overall, we did not detect any clear effects of herbivory or mechanical leaf damage on the chemical or physical leaf traits, despite clear effect of herbivory on photosynthesis. Rather, the trait variation was primarily driven by variation between individual trees. Only leaf nitrogen content and a subset of the studied polyphenol compounds correlated with photosynthesis and leaf respiration. Our results suggest that in our study system, abiotic conditions related to the growth location, variation between tree individuals, and seasonal trends in plant physiology are more important than herbivory in determining the distribution and composition of leaf chemical and structural traits

Fruit dry weight and quality of 'bing' sweet cherries grown without source limitations

Understanding the seasonal pattern of potential fruit growth is important for identification and timing of possible management operations, and quantification of this pattern is an important prerequisite to serve as input for crop growth models. `Bing¿ sweet cherry trees were heavily thinned at 63 degree-days (DD) (=8 days) after full bloom so weight and quality of the remaining fruit could be monitored under conditions of limiting and non-limiting carbohydrate supply. The effect of fruit thinning on mean shoot growth and trunk cross-sectional area also was analysed to detect possible translocation from reproductive to vegetative growth. Mean Fruit Dry Weight (MFDW) of tagged fruit was estimated weekly, based on fruit diameter, to identify the moment of the onset of competition between fruit within trees. At harvest, Fruit Number to Leaf Area Ratio (FNLAR, fruits m-2 LA) was 52% lower in heavily-thinned trees than in non-thinned trees. Yield per tree was higher (