Dust accumulation due to anthropogenic impact induces anatomical and photochemical changes in leaves of Centranthus ruber growing on the slope of the Vesuvius volcano

Effect of Organic Manure and Moisture Regimes on Soil Physiochemical Properties, Microbial Biomass Cmic:Nmic:Pmic Turnover and Yield of Mustard Grains in Arid Climate

(1) Background: Arid conditions occur due to climate abnormality in the different biogeography regions of the world. The aim of this research is to investigate the stoichiometry of manure and moisture regimes on soil properties, microbial biomass C:N:P turnover, and the grain yield of mustard crops under stress in arid conditions; (2) Methods: The field experiment was carried out for 2 years at the farms of the agriculture college of SKN, Jobner (SKRAU Bikaner, Rajasthan). The effects of organic manure, moisture regimes, and saline water treatment on soil properties, such as the soil microbial biomass build-up, loss, turnover, and recycling of carbon (C_mic), nitrogen (N_mic), and phosphorus (P_mic) in the mustard crop were investigated. The twenty-seven treatments studied are described as follows: organic manures (control, FYM @ 10 t ha^-1 and vermicompost @ 5 t ha^-1), moisture regimes (0.4, 0.6, and 0.8 IW/CPE ratio), and saline irrigation water (control, 6, 12 dSm^-1); (3) Results: Our findings indicate that vermicompost @ 5 t ha^-1 significantly increases moisture retention and the available water in soil at 33 kPa and 1500 kPa. The microbial biomass build-up of C_mic increases by 43.13% over the control and 14.36% over the FYM. Similarly, the soil microbial biomass of N_mic, and P_mic also increase considerably. The SHC of the soil is enhanced by the application of farmyard fertilizer and vermicompost. The BD and pH decrease significantly, while the SHC, OC, CEC, and ECe of the soil increase significantly. The build-up, losses, and fluxes of the soil microbial biomass of C_mic, N_mic, and P_mic increase significantly, and the turnover rate decreases under vermicompost @ 5 t ha^-1. A significant increase in grain yield was observed. Irrigation with a 0.8 IW/CPE moisture regime significantly decreases the pH of the SHC; (4) Conclusions: We hypothesized the interactive outcomes of the moisture regime and found that organic manure significantly influenced grain and stover yield. The treatments of quality irrigation water and the addition of organic manure are efficient enough to improve soil properties, water holding capacity, and soil microbial biomass C:N:P in stress climatic conditions.

Changes in Morpho-Anatomical and Eco-Physiological Responses of Viburnum tinus L. var lucidum as Modulated by Sodium Chloride and Calcium Chloride Salinization

Salinity in water and soil is among the major constraints to the cultivation of ornamental crops since it can affect their growth and aesthetic value. A greenhouse experiment was carried out to assess whether the application of two different salts (80 mM NaCl or 53.3 mM CaCl2, with a final ionic concentration of 160 mM) could differently modulate the anatomical and physiological acclimation of an important ornamental species such as Viburnum tinus L. var. lucidum. Eco-physiological analyses (e.g., leaf gas exchange and chlorophyll a fluorescence emission) were performed and leaves were subjected to light microscopy analysis to quantify functional anatomical traits through digital image analysis. Results showed that the two iso-osmotic solutions induced different structure-mediated physiological alterations in V. tinus plants. Photosynthesis was lowered by CaCl2 treatments (−58%) more than by NaCl (−37%), also due to the occurrence of photodamage apart from stomatal limitations. Neither Na+ nor Cl− exhibited toxic effects in leaf lamina structure which was reflected in the limited reduction in dry matter accumulation. Overall data were interpreted focusing on the coordination among leaf structural and functional traits suggesting that the fine control of functional anatomical traits contributes to physiological acclimation to both stressful conditions.

Facing metal stress by multiple strategies: morphophysiological responses of cardoon (Cynara cardunculus L.) grown in hydroponics

The contamination of environments by heavy metals has become an urgent issue causing undesirable accumulations and severe damages to agricultural crops, especially cadmium and lead which are among the most widespread and dangerous metal pollutants worldwide. The selection of proper species is a crucial step in many plant-based restoration approaches; therefore, the aim of the present work was to check for early morphophysiological responsive traits in three cultivars of Cynara cardunculus (Sardo, Siciliano, and Spagnolo), helping to select the best performing cultivar for phytoremediation. For all three tested cultivars, our results indicate that cardoon displays some morphophysiological traits to face Cd and Pb pollution, particularly at the root morphology level, element uptake ability, and photosynthetic pigment content. Other traits show instead a cultivar-specific behavior; in fact, stomata plasticity, photosynthetic pattern, and antioxidant power provide different responses, but only Spagnolo cv. achieves a successful strategy attaining a real resilience to metal stress. The capacity of Spagnolo plants to modify leaf structural and physiological traits under heavy metal contamination to maintain high photosynthetic efficiency should be considered an elective trait for its use in contaminated environments.

Modulating Vapor Pressure Deficit in the Plant Micro-Environment May Enhance the Bioactive Value of Lettuce

Growing demand for horticultural products of accentuated sensory, nutritional, and functional quality traits has been driven by the turn observed in affluent societies toward a healthy and sustainable lifestyle relying principally on plant-based food. Growing plants under protected cultivation facilitates more precise and efficient modulation of the plant microenvironment, which is essential for improving vegetable quality. Among the environmental parameters that have been researched for optimization over the past, air relative humidity has always been in the background and it is still unclear if and how it can be modulated to improve plants’ quality. In this respect, two differentially pigmented (green and red) Salanova® cultivars (Lactuca sativa L. var. capitata) were grown under two different Vapor Pressure Deficits (VPDs; 0.69 and 1.76 kPa) in a controlled environment chamber in order to appraise possible changes in mineral and phytochemical composition and in antioxidant capacity. Growth and morpho-physiological parameters were also analyzed to better understand lettuce development and acclimation mechanisms under these two VPD regimes. Results showed that even though Salanova plants grown at low VPD (0.69 kPa) increased their biomass, area, number of leaves and enhanced Fv/Fm ratio, plants at high VPD increased the levels of phytochemicals, especially in the red cultivar. Based on these results, we have discussed the role of high VPD facilitated by controlled environment agriculture as a mild stress aimed to enhance the quality of leafy greens.