Characteristics of Three Organic Fertilizers and Their Influence on the Mobility of Cadmium and Arsenic in a Soil-Rice (Oryza Sativa L.) System

The properties and effects of organic fertilizers are different, including the ability to improve soil fertility and the potential of stabilizing heavy metals in soils that have not been explored in depth. In this study, three organic fertilizers from different raw materials were characterized and evaluated. The mushroom residue organic fertilizer (MO) had higher C, H, and O contents and more functional groups (-OH, C-H, and C=O), and its application significantly increased pH (1.00~1.32 units), organic matter (OM) content (26.58%~69.11%) and cation exchange capacity (CEC) (31.52%~39.91%) of soil. MO treatment also reduced the toxicity characteristic leaching procedure (TCLP)-Cd (24.21%) and TCLP-As (18.44%) concentration in the soil. That inhibited the mobilization of Cd and As from soil to plant, especially to plant shoots, and positively affected the plant growth and biomass. Redundancy analysis (RDA) showed that 40.09 % of total plant variation was related to soil properties (pH, OM, and CEC). Furthermore, the heavy metal risk assessment for all organic fertilizers was at safe levels. This study provides a valuable reference for the selection of organic fertilizers. Besides, it recommends organic fertilizers as economic and multi-effect amendments with safe use and provides a new option for the ‘simultaneous production and remediation’ of farmlands with low pollution.

Is There More to Within-plant Variation in Seed Size than Developmental Noise?

Within-plant variation in seed size may merely reflect developmental instability, or it may be adaptive in facilitating diversifying bet-hedging, that is, production of phenotypically diverse offspring when future environments are unpredictable. To test the latter hypothesis, we analyzed patterns of variation in seed size in 11 populations of the perennial vine Dalechampia scandens grown in a common greenhouse environment. We tested whether population differences in the mean and variation of seed size covaried with environmental predictability at two different timescales. We also tested whether within-plant variation in seed size was correlated with independent measures of floral developmental instability and increased under stressful conditions. Populations differed genetically in the amount of seed-size variation occurring among plants, among infructescences within plants, and among seeds within infructescences. Within-individual variation was not detectably correlated with measures of developmental instability and did not increase under stress, but it increased weakly with short-term environmental unpredictability of precipitation at the source-population site. These results support the hypothesis that greater variation in seed size is adaptive when environmental predictability is low.

Hidden Fungi: Combining Culture-Dependent and -Independent DNA Barcoding Reveals Inter-Plant Variation in Species Richness of Endophytic Root Fungi in Elymus repens

The root endophyte community of the grass species Elymus repens was investigated using both a culture-dependent approach and a direct amplicon sequencing method across five sites and from individual plants. There was much heterogeneity across the five sites and among individual plants. Focusing on one site, 349 OTUs were identified by direct amplicon sequencing but only 66 OTUs were cultured. The two approaches shared ten OTUs and the majority of cultured endophytes do not overlap with the amplicon dataset. Media influenced the cultured species richness and without the inclusion of 2% MEA and full-strength MEA, approximately half of the unique OTUs would not have been isolated using only PDA. Combining both culture-dependent and -independent methods for the most accurate determination of root fungal species richness is therefore recommended. High inter-plant variation in fungal species richness was demonstrated, which highlights the need to rethink the scale at which we describe endophyte communities.

Within-Plant Variation in Rosmarinus officinalis L. Terpenes and Phenols and Their Antimicrobial Activity against the Rosemary Phytopathogens Alternaria alternata and Pseudomonas viridiflava

This study investigated within-plant variability of the main bioactive compounds in rosemary (Rosmarinus officinalis L.). Volatile terpenes, including the enantiomeric distribution of monoterpenes, and phenols were analyzed in young and mature foliar, cortical and xylem tissues. In addition, antimicrobial activity of rosmarinic acid and selected terpenes was evaluated against two rosemary pathogens, Alternaria alternata and Pseudomonas viridiflava. Data showed that total concentration and relative contents of terpenes changed in relation to tissue source and age. Their highest total concentration was observed in the young leaves, followed by mature leaves, cortical and xylem tissues. Rosmarinic acid and carnosic acid contents did not show significant differences between leaf tissues of different ages, while young and mature samples showed variations in the content of four flavonoids. These results are useful for a more targeted harvesting of rosemary plants, in order to produce high-quality essential oils and phenolic extracts. Microbial tests showed that several terpenes and rosmarinic acid significantly inhibited the growth of typical rosemary pathogens. Overall, results on antimicrobial activity suggest the potential application of these natural compounds as biochemical markers in breeding programs aimed to select new chemotypes less susceptible to pathogen attacks, and as eco-friendly chemical alternatives to synthetic pesticides.

Assessment phenotypic diversity of rice (Oryza sativa L.) genotypes by multivariate analysis

An efficient way to achieve superior productivity is to determine the genetic variation of the various rice genotypes. This research was aimed at estimating potential variations between rice genotypes and identifying each trait contribution in total variation and classifying superior genotypes. The experiment was performed at the Rice Research and Training Centre, Sakha, Kafr El-Sheik, Egypt. Twenty-two genotypes of rice were analyzed using seven agronomic traits. Multivariate approaches were utilized including principal components and cluster analysis. Results showed that PC1 and PC2 represented 66.1% of the variation between studied genotypes, mainly 48% because of grain yield per plant variation in PC1 followed by the characteristics of its components i.e., number of panicles per plant, number of filled grains per panicle, and 1000-grain weight. The three Egyptian rice genotypes Giza 181, Giza 178, and Giza 177 were the best genotypes for grain yield. Cluster results revealed that the majority of genotypes originated from one source (except for Indian variety IET1444) or belonged to one classification were clustered together. Multivariate analytical approaches are ideal instruments for providing information on agronomic character variations. Consequently, the results of the current study should be taken into account when developing new rice varieties.

The Assessment and the Within-Plant Variation of the Morpho-Physiological Traits and VOCs Profile in Endemic and Rare Salvia ceratophylloides Ard. (Lamiaceae)

Salvia ceratophylloides (Ard.) is an endemic and rare plant species recently rediscovered as very few individuals at two different Southern Italy sites. The study of within-plant variation is fundamental to understand the plant adaptation to the local conditions, especially in rare species, and consequently to preserve plant biodiversity. Here, we reported the variation of the morpho-ecophysiological and metabolic traits between the sessile and petiolate leaf of S. ceratophylloides plants at two different sites for understanding the adaptation strategies for surviving in these habitats. The S. ceratophylloides individuals exhibited different net photosynthetic rate, maximum quantum yield, light intensity for the saturation of the photosynthetic machinery, stomatal conductance, transpiration rate, leaf area, fractal dimension, and some volatile organic compounds (VOCs) between the different leaf types. This within-plant morpho-physiological and metabolic variation was dependent on the site. These results provide empirical evidence of sharply within-plant variation of the morpho-physiological traits and VOCs profiles in S. ceratophylloides, explaining the adaptation to the local conditions.

The Assessment and the Within-Plant Variation of the Morpho-Physiological Traits and VOCs Profile in Endemic and Rare Salvia ceratophylloides Ard. (Lamiaceae)

Salvia ceratophylloides (Ard.) is an endemic, rare, threatened plant species recently rediscovered in very few individuals in two different sites of South Italy. The study of within-plant variation more than among-plant one is fundamental to understand the plant adaptation to the local conditions, especially in rare species, and consequently to preserve plant biodiversity. Here, we reported the variation of the morpho-ecophysiological and metabolic traits between the sessile and petiolate leaf of S. ceratophylloides plants in two different sites for understanding the adaptation strategies for surviving in these habitats. The S. ceratophylloides individuals exhibited different net photosynthetic rate, maximum quantum yield, light intensity for the saturation of the photosynthetic machinery, stomatal conductance, transpiration rate, leaf area, fractal dimension and some VOCs between the different leaf types. This within-plant morpho-physiological and metabolic variation was depended on the site. These results provide empirical evidence of sharply within-plant variation of the morpho-physiological traits and VOCs profiles in S. ceratophylloides which could be because of adaptation to the local conditions.

Divergence in bidirectional plant-soil feedbacks between montane annual and coastal perennial ecotypes of yellow monkeyflower (Mimulus guttatus)

SUMMARYUnderstanding the physiological and genetic mechanisms underlying plant variation in interactions with root-associated biota (RAB) requires a micro-evolutionary approach. We use locally adapted montane annual and coastal perennial ecotypes of Mimulus guttatus (yellow monkeyflower) to examine population-scale differences in plant-RAB-soil feedbacks.We characterized fungal communities for the two ecotypes in-situ and used a full-factorial greenhouse experiment to investigate the effects of plant ecotype, RAB source, and soil origin on plant performance and endophytic root fungal communities.The two ecotypes harbored different fungal communities and responsiveness to soil biota was highly context-dependent. Soil origin, RAB source, and plant ecotype all affected the intensity of biotic feedbacks on plant performance. Feedbacks were primarily negative, and we saw little evidence of local adaptation to either soils or RAB. Both RAB source and soil origin significantly shaped fungal communities in roots of experimental plants. Further, the perennial ecotype was more colonized by arbuscular mycorrhizal fungi (AMF) than the montane ecotype, and preferentially recruited home AMF taxa.Our results suggest life history divergence and distinct edaphic habitats shape plant responsiveness to RAB and influence specific associations with potentially mutualistic root endophytic fungi. Our results advance the mechanistic study of intraspecific variation in plant–soil–RAB interactions.

The Floral Microbiome: Plant, Pollinator, and Microbial Perspectives

Flowers at times host abundant and specialized communities of bacteria and fungi that influence floral phenotypes and interactions with pollinators. Ecological processes drive variation in microbial abundance and composition at multiple scales, including among plant species, among flower tissues, and among flowers on the same plant. Variation in microbial effects on floral phenotype suggests that microbial metabolites could cue the presence or quality of rewards for pollinators, but most plants are unlikely to rely on microbes for pollinator attraction or reproduction. From a microbial perspective, flowers offer opportunities to disperse between habitats, but microbial species differ in requirements for and benefits received from such dispersal. The extent to which floral microbes shape the evolution of floral traits, influence fitness of floral visitors, and respond to anthropogenic change is unclear. A deeper understanding of these phenomena could illuminate the ecological and evolutionary importance of floral microbiomes and their role in the conservation of plant–pollinator interactions.

Larvicidal activity of aqueous extracts of Ilex paraguariensis and Ilex theezans on Aedes aegypti (L.)

Aedes aegypti is the main vector of Dengue, Yellow Urban Fever, Chikungunya fever and Zika virus fever. The strategies for its control include synthetic products that cause damage to the environment and other organisms. This study evaluated the larvicidal activity of aqueous extracts of leaves and fruits of Ilex paraguariensis and Ilex theezans on Aedes aegypti mosquito larvae. The bioassays were conducted at the Ecological Entomology Laboratory, Unochapecó, under controlled conditions of temperature and photoperiod. The extracts of fresh and dried leaves of I. theezans showed greater larvicidal activity when compared to extracts of fruits of the same plant. Variation in larvicidal activity was also observed during exposure periods. The results suggest the use of extracts of these plants in the control of A. aegypti and the prospection of substances that can be used as an alternative to synthetic products. They point to the possibility of using yerba mate tissues that are not used commercially.