Growth, leaf gas exchange and mycorrhizal colonization of three medicinal species submitted to different irradiance levels

ABSTRACT: This study o evaluated growth, leaf gas exchange and arbuscular mycorrhizal fungi root colonization in three medicinal plant species under different irradiance intensities. Fridericia chica (Bonpl.) L.G.Lohmann, Mikania laevigata Sch.Bip. ex Baker and Varronia curassavica Jacq. were propagated by cutting and cultivated for 120 days in artificially shaded environments using black shade-type screens, obtaining four irradiance levels: 100%, 70%, 50% and 30%. The experimental design was completely randomized in a 3 x 4 factorial scheme (three plant species and four irradiation levels) with seven replicates. The three medicinal species showed higher liquid assimilation, mass growth and arbuscular mycorrhizal fungi root colonization rates when exposed to environments with 70% light availability. In relation to physiological responses, V. curassavica presented higher photosynthetic rate, stomatal conductance and transpiration when submitted to 70% irradiance, being able to be cultivated in more open environments with higher irradiation levels. Conversely F. chica and M. laevigata presented shade tolerance characteristics. At the initial growth phase, the results obtained can be used as indicators to recommend the ideal cultivation environment for these species in agroforestry systems.

Root deformation affects mineral nutrition but not leaf gas exchange and growth of Genipa americana seedlings during the recovery phase after soil flooding

Root deformation (RD) caused by errors in the pricking out process are irreversible and very difficult to detect in container-grown seedlings at the time of planting in the field. The objective of this study was to evaluate the effects of RD on leaf gas exchange, growth, biomass allocation and mineral nutrition of G. americana seedlings during the recovery phase after soil flooding. Four-months-old seedlings, with and without RD, were flooded for 42 days and their recovery was evaluated 28 days after soil drainage. There were no significant interactions between RD and soil flooding for all leaf gas exchange, growth and mineral nutrition after soil drainage, with the exception of leaf P concentrations. In plants with no RD, the P concentration in leaves of non-flooded plants was significantly higher than that of plants with RD. Soil flooding and RD did not influence leaf or root N concentrations or whole-plant N content. RD increased the K concentration in the roots, but not in the leaves. Changes in the nutrient concentrations in leaves and roots indicate that RD may affect physiological performance of seedlings after planting in the field.

Influence of drought stress on growth, biochemical changes and leaf gas exchange of strawberry (Fragaria × ananassa Duch.) in Indonesia

<abstract> <p>Drought stress is one of the challenges that can affect the growth and the quality of strawberry. The study aims to determine the growth, biochemical changes and leaf gas exchange of three strawberry cultivars under drought stress. This study was conducted in a glasshouse at Indonesian Citrus and Subtropical Fruits Research Institute, Indonesia, from July-November 2018. The experiment was arranged in a factorial randomized completely block design (RCBD) with three replications and four water deficit (WD) levels [100% field capacity (FC)/well-watered), 75% of FC (mild WD), 50% of FC (moderate WD), and 25% of FC (severe WD)] for three strawberry cultivars (Earlibrite, California and Sweet Charlie). The results showed that total chlorophyll and anthocyanin contents (p ≤ 0.05) were influenced by the interaction effects of cultivars and water deficit. Whereas other parameters such as plant growth, transpiration rate (<italic>E</italic>), net photosynthesis (<italic>A</italic>), stomatal conductance (<italic>gs</italic>), leaf relative water content (LRWC), flowers and fruits numbers, proline content, length, diameter, weight and total soluble solid (TSS) of fruit were affected by water deficit. <italic>A</italic> had positive significant correlation with plant height (r = 0.808), leaf area (r = 0.777), fruit length (r = 0.906), fruit diameter (r = 0.889) and fruit weight (r = 0.891). Based on the results, cultivars affected LRWC, and also number of flowers and fruits of the strawberry. This study showed that water deficit decreased plant growth, chlorophyll content, leaf gas exchange, leaf relative water content, length, diameter and weight of fruit but enhanced TSS, anthocyanin, MDA, and proline contents. Increased anthocyanin and proline contents are mechanisms for protecting plants against the effects of water stress. California strawberry had the highest numbers of flowers and fruits, and also anthocyanin content. Hence, this cultivar is recommended to be planted under drought stress conditions. Among all water stress treatments, 75% of FC had the best results to optimize water utilization on the strawberry plants.</p> </abstract>

Vanadium Toxicity Induced Changes in Growth, Antioxidant Profiling, and Vanadium Uptake in Pepper (Capsicum annum L.) Seedlings

Heavy metal contamination is one of the current serious environmental and agricultural soil issues, and it is mainly due to anthropogenic activities. Vanadium (V) is found in low concentrations in a wide range of plants and is widely distributed in soils. The current study aimed to determine how pepper seedlings responded to various V concentrations, as well as the detrimental effects of V on growth, root morphological traits, photosynthetic performance, reactive oxygen species (ROS), osmolytes production, antioxidant enzyme activities, and V uptake. Pepper seedlings (5 weeks old) were grown in hydroponic culture with six V levels (0, 10, 20, 30, 40, and 50 mg L−1 NH4VO3). After two weeks of V treatment, low level of V (10, 20 mg L−1) enhanced the growth status, conversely higher V (30, 40, and 50 mg L−1) level reduced the growth. The leaf gas exchange elements, pigments molecules, and root growth characteristics are also affected by higher V concentrations. Moreover, V uptake was higher in roots than in the shoot of pepper seedlings. Similarly, osmolytes content, ROS production, and antioxidant enzymes activities were significantly improved under V stress. Concluding, lower V (10, 20 mg L−1) concentration positively affected pepper growth, and higher V (30, 40, and 50 mg L−1) concentration had a detrimental effect on pepper physiological and biochemical mechanisms.

Particulate Matter (PM) Adsorption and Leaf Characteristics of Ornamental Sweet Potato (Ipomoea batatas L.) Cultivars and Two Common Indoor Plants (Hedera helix L. and Epipremnum aureum Lindl. & Andre)

Particulate matter (PM) is a serious threat to human health, climate, and ecosystems. Furthermore, owing to the combined influence of indoor and outdoor particles, indoor PM can pose a greater threat than urban PM. Plants can help to reduce PM pollution by acting as biofilters. Plants with different leaf characteristics have varying capacities to capture PM. However, the PM mitigation effects of plants and their primary factors are unclear. In this study, we investigated the PM adsorption and leaf characteristics of five ornamental sweet potato (Ipomea batatas L.) cultivars and two common indoor plants (Hedera helix L. and Epipremnum aureum Lindl. & Andre) exposed to approximately 300 μg m−3 of fly ash particles to assess the factors influencing PM adsorption on leaves and to understand the effects of PM pollution on the leaf characteristics of plants. We analyzed the correlation between PM adsorption and photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), leaf area (LA), leaf width/length ratio (W/L), stomatal density (SD), and stomatal pore size (SP). A Pearson’s correlation analysis and a principal component analysis (PCA) were used to evaluate the effects of different leaf characteristics on PM adsorption. The analysis indicated that leaf gas exchange factors, such as Pn and Tr, and morphological factors, such as W/L and LA, were the primary parameters influencing PM adsorption in all cultivars and species tested. Pn, Tr, and W/L showed a positive correlation with PM accumulation, whereas LA was negatively correlated.

Rootstock-Mediated Genetic Variance in Cadmium Uptake by Juvenile Cacao (Theobroma cacao L.) Genotypes, and Its Effect on Growth and Physiology

Grafting typically offers a shortcut to breed tree orchards throughout a multidimensional space of traits. Despite an overwhelming spectrum of rootstock-mediated effects on scion traits observed across several species, the exact nature and mechanisms underlying the rootstock-mediated effects on scion traits in cacao (Theobroma cacao L.) plants often remain overlooked. Therefore, we aimed to explicitly quantify rootstock-mediated genetic contributions in recombinant juvenile cacao plants across target traits, specifically cadmium (Cd) uptake, and its correlation with growth and physiological traits. Content of chloroplast pigments, fluorescence of chlorophyll a, leaf gas exchange, nutrient uptake, and plant biomass were examined across ungrafted saplings and target rootstock × scion combinations in soils with contrasting levels of Cd. This panel considered a total of 320 progenies from open-pollinated half-sib families and reciprocal full-sib progenies (derived from controlled crosses between the reference genotypes IMC67 and PA121). Both family types were used as rootstocks in grafts with two commercial clones (ICS95 and CCN51) commonly grown in Colombia. A pedigree-based best linear unbiased prediction (A-BLUP) mixed model was implemented to quantify rootstock-mediated narrow-sense heritability (h2) for target traits. A Cd effect measured on rootstocks before grafting was observed in plant biomass, nutrient uptake, and content of chloroplast pigments. After grafting, damage to the Photosystem II (PSII) was also evident in some rootstock × scion combinations. Differences in the specific combining ability for Cd uptake were mostly detected in ungrafted rootstocks, or 2 months after grafting with the clonal CCN51 scion. Moderate rootstock effects (h2&gt; 0.1) were detected before grafting for five growth traits, four nutrient uptake properties, and chlorophylls and carotenoids content (h2 = 0.19, 95% CI 0.05–0.61, r = 0.7). Such rootstock effects faded (h2&lt; 0.1) when rootstock genotypes were examined in soils without Cd, or 4 months after grafting. These results suggest a pervasive genetic conflict between the rootstock and the scion genotypes, involving the triple rootstock × scion × soil interaction when it refers to Cd and nutrient uptake, early growth, and photosynthetic process in juvenile cacao plants. Overall, deepening on these findings will harness early breeding schemes of cacao rootstock genotypes compatible with commercial clonal scions and adapted to soils enriched with toxic levels of Cd.

Effects of natural clinoptilolite on physiology, water stress, sugar, and anthocyanin content in Sanforte (Vitis vinifera L.) young vineyard

In the Mediterranea area, major effects of climate change are a modification in rainfall patterns, an increase in temperature with an intensify in tropical nights, and an increase in incoming radiations, especially UV-Bs. Despite the various adaptation strategies, grapevines are sensitive to altered climatic conditions. This paper aims to assess the benefits of applying a new sustainable product to the soil that can implement farmers’ resources to adapt to this changing situation. Zeowine was realized by combining the properties of zeolite, which has excellent potential in many sectors such as in agriculture, with the organic substance of a compost obtained on a company scale from the reuse of waste processing grapes, pomace and stalks. The effects of two different soil management (Z – Zeowine, 30 t/ha dose and C – Compost, 20 t/ha dose) on vine physiology and berry compositions in Sanforte grapevines (new plantation) were studied during the 2019–2020–2021 growing seasons in the San Miniato area, Italy. The following physiological parameters of grapevines were measured: leaf gas exchange, leaf temperature, stem water potential and chlorophyll fluorescence. The results showed that Z increased single leaf photosynthesis, reduced leaf temperature and water stress. In addition, phenolic and technological parameters were studied. The Z-treated vines had higher sugar content and total and extractable anthocyanin content as well as berry weight. These results suggested that the application of zeolites added to compost in the vineyard to the soil can be a valid tool to mitigate the effects of climate change.