Woody species distribution across a savanna-dry forest soil gradient in the Brazilian Cerrado

Although richness and distribution of woody species in the Cerrado physiognomies have been extensively studied, the shifts of woody species from savanna physiognomies to dry forests have not yet been addressed. Here, we investigate the effect of soil physical-chemical traits on the woody species turnover between adjacent cerrado stricto sensu and dry forest physiognomies. Woody species were surveyed, and soil and topographic variables measured, in 30 10×40 m plots systematically distributed, with 15 plots in each physiognomy. We found a spatially structured distribution of woody species, and differences of soil traits between cerrado stricto sensu and dry forest areas, mainly related to the aluminum saturation, base saturation, and available phosphorus. Aluminum saturation increased toward the savanna area, while base saturation increased toward the dry forest. Most woody species predominated in one physiognomy, such as Callisthene major in the cerrado stricto sensu and Anadenanthera colubrina in the dry forest. Only 20% of the species were widely distributed across both physiognomies or, not often, restricted to the intermediary values of the soil gradient. General results indicate that contrasting soil traits between cerrado stricto sensu and dry forest produce a strongly spatially organized and sharp transition in terms of species distribution between these physiognomies.

Shift from Acquisitive to Conservative Root Resource Acquisition Strategy Associated with Increasing Tree Age: A Case Study of Fraxinus mandshurica

Tree age has an important effect on the form and function of fine roots. Previous studies have focused on the variations in root morphological and chemical traits among tree ages, while less attention has been given to the physiological traits, impeding a full understanding of the relationship between root resource acquisition strategy and tree age. Here, we measured root morphological (diameter, specific root length, specific root area and tissue density), chemical (nitrogen concentration) and physiological (respiration and exudation rate) traits of young, middle-aged and mature trees of Fraxinus mandshurica in a temperate secondary forest in northeastern China. Our overall aim was to determine how root traits and related resource acquisition strategy change with tree age. The results showed that from young to mature trees, root diameter gradually increased, but specific root length, specific root area, root nitrogen concentration, respiration and exudation rates all decreased, and the significant differences were mainly found between young and mature trees. Pearson’s correlation analysis revealed that the relationships of root respiration and exudation rates to root morphological and chemical traits depended on tree age and the specific traits examined, but these correlations were all significant except for root tissue density when the data were pooled across all tree age classes. Principal component analysis (PCA) showed that the conservative traits represented by root diameter, and the acquisitive traits such as root respiration and exudation rates and related morphological and chemical traits, occupied two ends of the first axis, respectively, while root tissue density occupied one end of the second axis, partially confirming the conceptual framework of “root economics space”. Standardized major axis (SMA) analysis of root exudation and respiration rates showed that young trees allocated more root carbon flux to the formation of root exudation, compared to middle-aged and mature trees. Our findings suggest that root resource acquisition strategy in F. mandshurica appears to shift from an absorptive to conservative strategy associated with increasing tree age, which may have substantial consequences for individual growth and interspecific competition, as well as belowground carbon allocation in ecosystems.

Quality Traits, Volatile Organic Compounds, and Expression of Key Flavor Genes in Strawberry Genotypes over Harvest Period

Six strawberry genotypes were examined for fruit yield and size, important chemical traits (sugars, phenolics, anthocyanins, ascorbic acid, volatiles) and antioxidant properties (ferric reducing power). In addition, we determined the expression of genes and transcription factors (SAAT, FaNES1, FaFAD1, FaEGS2, FaEOBII and FaMYB10) controlling the main flavor and aroma traits, and finally evaluated the effect of the genotype and harvest time on the examined chemical and genetic factors, as well as their intercorrelations. The commercial varieties ‘Fortuna’, ‘Victory’, ‘Calderon’, ‘Rociera’, and two advanced selections Ber22/6 and Ber23/3 were cultivated under the same conditions at Berryplasma World Ltd. plantations (Varda, Ilia, Region of Western Greece). Strawberries were harvested at three different time points over the main harvest period in Greece, i.e., early March (T1), late March (T2) and late April (T3). ‘Fortuna’ exhibited the highest early and total yield, while ‘Calderon’, the highest average berry weight. General Linear Model repeated measures ANOVA demonstrated that the interaction of the genotype and harvest time was significant (p < 0.001) on all tested quality attributes and gene expression levels, showing that each genotype behaves differently throughout the harvest period. Exceptions were observed for: (a) the volatile anhydrides, fatty acids, aromatics and phenylpropanoids (all were greatly affected by the harvest time), and (b) lactones, furaneol and FaEGS2 that were affected only by the genotype. We observed significant intercorrelations among those factors, e.g., the positive correlation of FaFAD1 expression with decalactone and nerolidol, of SAAT with furaneol, trans-cinnamic acid and phenylpropanoids, and of FaEGS2 with decalactone and FaFAD1. Moreover, a strong positive correlation between SAAT and FaMYB10 and a moderate negative one between SAAT and glucose were also detected. Those correlations can be further investigated to reveal potential markers for strawberry breeding. Overall, our study contributes to a better understanding of strawberry physiology, which would facilitate breeding efforts for the development of new strawberry varieties with superior qualitative traits.

Darkfield and Fluorescence Macrovision of a Series of Large Images to Assess Anatomical and Chemical Tissue Variability in Whole Cross-Sections of Maize Stems

The proportion and composition of plant tissues in maize stems vary with genotype and agroclimatic factors and may impact the final biomass use. In this manuscript, we propose a quantitative histology approach without any section labelling to estimate the proportion of different tissues in maize stem sections as well as their chemical characteristics. Macroscopic imaging was chosen to observe the entire section of a stem. Darkfield illumination was retained to visualise the whole stem cellular structure. Multispectral autofluorescence images were acquired to detect cell wall phenolic compounds after UV and visible excitations. Image analysis was implemented to extract morphological features and autofluorescence pseudospectra. By assimilating the internode to a cylinder, the relative proportions of tissues in the internode were estimated from their relative areas in the sections. The approach was applied to study a series of 14 maize inbred lines. Considerable variability was revealed among the 14 inbred lines for both anatomical and chemical traits. The most discriminant morphological descriptors were the relative amount of rind and parenchyma tissues together with the density and size of the individual bundles, the area of stem and the parenchyma cell diameter. The rind, as the most lignified tissue, showed strong visible-induced fluorescence which was line-dependant. The relative amount of para-coumaric acid was associated with the UV-induced fluorescence intensity in the rind and in the parenchyma near the rind, while ferulic acid amount was significantly correlated mainly with the parenchyma near the rind. The correlation between lignin and the tissue pseudospectra showed that a global higher amount of lignin resulted in a higher level of lignin fluorescence whatever the tissues. We demonstrated here the potential of darkfield and autofluorescence imaging coupled with image analysis to quantify histology of maize stem and highlight variability between different lines.

New species and records of Chapsa (Graphidaceae) in China

We studied the genus Chapsa in China based on morphological characteristics, chemical traits and molecular phylogenetic analysis. One species new to science (C. murioelongata M.Z. Dou &amp; M. Li) and two records new to China were found (C. wolseleyana Weerakoon, Lumbsch &amp; Lücking and C. niveocarpa Mangold). Chapsa murioelongatasp. nov. is characterised by its lobed thalline margin, orange discs with white pruina, clear hymenium, and submuriform and long ascospores. Chapsa wolseleyana was recombined into Astrochapsa based on phenotypic traits. Sequences of this species are for the first time reported here and phylogenetic analyses of three loci (mtSSU, ITS and nuLSU) supported the position of this species within Chapsa. A key for the Chapsa species known in China is provided.

Quality Evaluation of Wild and Cultivated Asparagus: A Comparison between Raw and Steamed Spears

Asparagus is highly appreciated for its organoleptic and nutritional characteristics and wild genotypes are valuable components of traditional dishes. In this study, the physical and chemical traits of wild (green and violet) and cultivated asparagus (‘Grande’, ‘Purple Passion’, and ‘Bianco di Bassano del Grappa’), both raw and steamed, were evaluated. Steaming did not affect the total phenols content with the exception of wild green (+49%) and ‘Grande’ (−31%). Only for wild violet asparagus steaming increased the total antioxidant activity (+46%). Chlorogenic acid and chicoric acid were found only in wild asparagus, while rutin was generally higher in colored cultivated asparagus than wild ones. The highest content of isorhamnetin-3-rutinoside was found in wild violet asparagus while only traces of this compound were detected in the cultivated ones. Steaming influenced the content of both chlorophylls and carotenoids in asparagus, also resulting in changes in the color parameters in cooked spears. Overall, the sugar content in wild asparagus was lower than in the cultivated ones and steaming had a low impact on this chemical trait. Principal component analysis highlighted the most evident separation between wild asparagus and cultivated ones. These results indicate that wild asparagus can be considered a nutritious and refined food, and provide specific information required for cooking process strategies in the agri-food industrial sector.

Morphometric Traits and iPBS Based Molecular Characterizations of Walnut (Juglans regia L.) Genotypes

In this study, walnut genotypes that selected during two growing seasons among thousands of seedlings were analyzed in terms of detailed morphometric, phenological, and chemical traits. A multivariate analysis was conducted with valuable traits for breeding and selection such as morphometric traits, chemical composition, and phenological characteristics. Also, genotypes were characterized by a retrotransposon-based iPBS marker system. The correlation analysis showed significant positive and negative correlations between agro-morphological characters. The principal component analysis explained 71.44% of the total variance into five main components. Principal component and hierarchical cluster analysis divided genotypes into three groups, whose subgroups were identified based on both agro-morphological characters and iPBS marker systems. A high level of polymorphism ratio was observed for tested markers. Mantel’s test demonstrated relatively low correlations between molecular and morphological treats (r=0.04). The genetic similarities among all individuals ranged from 0.39 (between 018 and 015 or 045 genotypes) to 0.98 (between 090 and 094 genotypes) with a mean similarity of 0.67. Remarkable phenotypic and molecular variations were observed among the genotypes. The features of some investigated genotypes were above the acceptable thresholds for walnut selection in breeding programs and our study indicated that iPBS markers can be beneficial in walnut breeding programs, allowing the evaluation of the genetic relationship between genotypes, helping to differentiate and select the best genotypes to improve agronomic properties.