The Impact of Salinity in the Irrigation of a Wild Underutilized Leafy Vegetable, Sonchus oleraceus L.

Introducing non- or under-utilized crops to cultivation generates benefits such as biodiversity enrichment, supporting mitigation actions towards climate change-induced effects. The salinization of soil and water supplies is progressively disrupting natural habitats and food production, especially in regions such as the Mediterranean. Sonchus oleraceus L. is a Mediterranean wild leafy green with nutritional and medicinal properties. This study's purpose was to determine whether salinity affects the growth, quality, and nutrient composition of Sonchus oleraceus L. In an unheated plastic greenhouse, seedlings were transplanted in pots filled with perlite and irrigated with a nutrient solution with no NaCl added (the control, C) or with the addition of 40, 60, 80, and 100 mM of NaCl (treatments S4, S6, S8, and S10, respectively). The leaf and root growth, leaf quality, and the nutrient composition of leaves and roots were determined. Regarding the results, growth was mainly affected at high salinity levels (S8 and S10), with no observed effects of salinity on the determined quality parameters. The nutrient composition was variably affected by salinity in leaves but not in roots (except in the case of Na and the K/Na ratio). Sonchus oleraceus L. showed a general relative tolerance in moderate salinity levels (40 and 60 mM of NaCl), suggesting potential commercial exploitation of the species in areas where the quality of irrigation water is low. However, the health effects of consuming this species grown under salinity stress need to be studied in future research.

DNA Barcoding and Fertilization Strategies in Sideritis syriaca subsp. syriaca, a Local Endemic Plant of Crete with High Medicinal Value.

Herein, we applied DNA barcoding for the genetic characterization of Sideritis syriaca subsp. syriaca (Lamiaceae; threatened local Cretan endemic plant) using seven molecular markers of cpDNA. Five fertilization schemes were evaluated comparatively in a pilot cultivation in Crete. Conventional inorganic fertilizers (ChFs), integrated nutrient management (INM) fertilizers, and two biostimulants were utilized (foliar and soil application). Plant growth, leaf chlorophyll fluorescence, and color were assessed and leaf content of chlorophyll, key antioxidants (carotenoids, flavonoids, phenols), and nutrients were evaluated. Fertilization schemes induced distinct differences in leaf shape, altering quality characteristics. INM-foliar and ChF-soil application promoted yield, without affecting tissue water content or biomass partitioning to inflorescences. ChF-foliar application was the most stimulatory treatment when the primary target was enhanced antioxidant contents while INM-biostimulant was the least effective one. However, when the primary target is yield, INM, especially by foliar application, and ChF, by soil application, ought to be employed. New DNA sequence datasets for the plastid regions of petB/petD, rpoC1, psbK-psbI, and atpF/atpH were deposited in the GenBank for S. syriaca subsp. syriaca while the molecular markers rbcL, trnL/trnF, and psbA/trnH were compared to those of another 15 Sideritis species retrieved from the GenBank, constructing a phylogenetic tree to show their genetic relatedness.

Leaf manganese and phenolics as proxies of soil acidification and phosphorus acquisition mechanisms in lentil cultivars on alkaline soil.

Leaf manganese (Mn) concentration has been used as a proxy for root exudation and phosphorus (P) uptake under controlled conditions, but there are limited field studies that confirm its validity. On an alkaline, P-poor soil, four lentil cultivars ('Samos', 'Thessaly', 'Flip', 'Algeria') received two P rates (0 and 26.2kgPha-1 ), for two growing seasons, to study whether aboveground assessments [leaf P, Mn, phenolic concentration (TPhe)] can approximate rhizosphere physiological traits related to P acquisition [soil acidification (ΔpH), arbuscular mycorrhizal fungi (AMF) colonisation, acid phosphatase activity (APase)]. Phosphorus addition had no effect on the determined traits. Cultivars differed in leaf P, Mn, TPhe and AMF, but there was no clear pattern relating aboveground traits to rhizosphere traits related to P acquisition, thus not confirming that leaf Mn can be a proxy of root exudation. Of three growth stages [V 7-8, R1 (first bloom), R4 (flat pod)], R1 seemed to be critical, showing the highest leaf P, ΔpH, AMF and TPhe. Precipitation and temperatures over the growing season were determinants of lentil responses affecting rhizosphere activity, soil P availability and finally leaf traits. In conclusion, in lentil on alkaline and P-limiting soils, high leaf Mn and phenolic concentration are not reliable indicators of rhizosphere P-acquiring mechanisms.

Adaptability of Wild-Growing Tulips of Greece: Uncovering Relationships between Soil Properties, Rhizosphere Fungal Morphotypes and Nutrient Content Profiles.

Wild-growing Greek tulips are protected plants but almost nothing is known about their natural nutrient status and rhizosphere fungal morphotypes in the wild, thus no insight is currently available into their growth and adaptation to their natural environment or artificial settings. To this end, several botanical expeditions were conducted with a special collection permit, and 34 tulip and soil samples were collected, representing 13 species from two phytogeographical regions of Greece (North Aegean Islands, Crete Island) and seven regions of mainland Greece. The tulips' content in essential macro- and micro-nutrients, respective physicochemical soil properties, and rhizosphere fungal morphotypes were assessed across samples, and all parameters were subjected to appropriate statistical analysis to determine their interrelationships. The results showed that soil variables played a significant role in shaping tulips' nutrient content, explaining up to 67% of the detected variability as in the case of phosphorus (P) in the above-ground plant tissue. In addition, significant correlations were observed (with an r value of up to 0.65, p < 0.001) between essential nutrients in the tulips, such as calcium (Ca) and boron (B). The principal component analysis (PCA) revealed that between the three spatial units examined, the total variability of tulips' nutrient content produced a clear distinction among sampled species, while the first two PCA axes managed to explain 44.3% of it. This was further confirmed by the analysis of variance (ANOVA) results which showed corresponding significant differences (at p < 0.05) in both the tulips' nutrient content and the studied soil properties as well (mean values of N, P, and K in the North Aegean Islands tulips' nutrient content, up to 53%, 119%, and 54% higher compared to those of the Crete Island, respectively). Our study sheds light on Greek tulips' adaptability and resilience in their original habitats, facilitating at the same time the undertaken efforts regarding their conservation and potential domestication in artificial settings.

The Effects of Quinone Imine, a New Potent Nitrification Inhibitor, Dicyandiamide, and Nitrapyrin on Target and Off-Target Soil Microbiota.

Dicyandiamide (DCD) and nitrapyrin (NP) are nitrification inhibitors (NIs) used in agriculture for over 40 years. Recently, ethoxyquin (EQ) was proposed as a novel potential NI, acting through its derivative quinone imine (QI). Still, the specific activity of these NIs on the different groups of ammonia-oxidizing microorganisms (AOM), and mostly their effects on other soil microbiota remain unknown. We determined the impact of QI, and comparatively of DCD and NP, applied at two doses (regular versus high), on the function, diversity, and dynamics of target (AOM), functionally associated (nitrite-oxidizing bacteria-NOB), and off-target prokaryotic and fungal communities in two soils mainly differing in pH (5.4 versus 7.9). QI was equally effective to DCD but more effective than NP in inhibiting nitrification in the acidic soil, while in the alkaline soil QI was less efficient than DCD and NP. This was attributed to the higher activity of QI toward AOA prevailing in the acidic soil. All NIs induced significant effects on the composition of the AOB community in both soils, unlike AOA, which were less responsive. Beyond on-target effects, we noted an inhibitory effect of all NIs on the abundance of NOB in the alkaline soil, with Nitrobacter being more sensitive than Nitrospira. QI, unlike the other NIs, induced significant changes in the composition of the bacterial and fungal communities in both soils. Our findings have serious implications for the efficiency and future use of NIs on agriculture and provide unprecedented evidence for the potential off-target effects of NIs on soil microbiota. IMPORTANCE NIs could improve N use efficiency and decelerate N cycling. Still, we know little about their activity on the distinct AOM groups and about their effects on off-target soil microorganisms. Here, we studied the behavior of a new potent NI, QI, compared to established NIs. We show that (i) the variable efficacy of NIs across soils with different pH reflects differences in the inherent specific activity of the NIs to AOA and AOB; (ii) beyond AOM, NIs exhibit negative effects on other nitrifiers, like NOB; (iii) QI was the sole NI that significantly affected prokaryotic and fungal diversity. Our findings (i) highlight the need for novel NI strategies that consider the variable sensitivity of AOM groups to the different NIs (ii) identify QI as a potent AOA inhibitor, and (iii) stress the need for monitoring NIs' impact on off-target soil microorganisms to ensure sustainable N fertilizers use and soil ecosystem functioning.

Phosphorus fertilisation may induce Zn deficiency in cotton (Gossypium hirsutum) on calcareous Mediterranean soils.

On a P-poor, calcareous soil, three upland cotton (Gossypium hirsutum L.) cultivars (ST 402, ST 405, Zeta 2) were tested for 2years under three P rates (0, 13.1, 26.2kgPha-1 ). Leaf traits (SPAD values; specific leaf area, SLA; carbon isotope discrimination, Δ; 15 N natural abundance, δ15 N) and elements (N, P, K, C, Na, Zn) along with arbuscular mycorrhizal (AM) colonisation were measured at first open flower, full bloom and first open boll stages. Phosphorus addition decreased yield, but had no effect on fibre quality, a response attributed to P-induced Zn deficiency, previously reported for cereals. The best-performing cv., ST 405, had high SPAD and SLA, but the lowest P, N and Zn concentrations, an indication of cultivar's high use efficiency for these nutrients. At full bloom, SPAD was lowest, while SLA was highest. AM increased gradually with growth stages, while N, P, K and Zn concentrations showed an opposite trend, possibly due to a dilution effect. On Mediterranean calcareous soils, P fertilisation should take into account soil Zn levels in order to avoid P-Zn antagonistic relationships, which could impact negatively on yield.

Greek Tulips: Worldwide Electronic Trade over the Internet, Global Ex Situ Conservation and Current Sustainable Exploitation Challenges.

From an ornamental viewpoint, tulips are famous clonally propagated crops. This research focuses on 15 wild-growing Greek tulip species including 11 range-restricted species, i.e., six Greek endemics and five Balkan or Aegean endemics and subendemics, among which seven are currently threatened with extinction (two Critically Endangered, three Endangered and two Vulnerable). An overview of the global electronic trade over the internet is presented herein for these valuable phytogenetic resources in an attempt to define the extent of their commercialization (25 nurseries in three countries, mainly bulb trade at various prices) with concomitant conservation implications. In the frame of the repatriation initiatives launched, their global ex situ conservation is overviewed according to the PlantSearch facility of the Botanic Gardens Conservation International (materials from 15 species stored in 41 botanic gardens of 14 countries). The results of this study on the Greek tulips showed that there are both well-established value chains and gaps in the market regarding the "botanical tulips"; revealed the compromised effectiveness of ex situ conservation for the majority of them; raised conservation concerns related to authorized access to these wild phytogenetic resources; and indicated that their future utilization should comply with the provision of national and international legislation. All these are envisaged and discussed within the framework of the newly launched research project TULIPS.GR which aims to be the pilot establishment of a national collection regarding all Greek tulips (currently holding 38 accessions of 13 species, including almost all of the threatened ones). The project's scope is to enable the creation of a sustainable value chain for the Greek tulips with authorized collections, sustainable conservation schemes, production of DNA barcoded propagation material, species-specific propagation and cultivation protocols, mycorrhizal investigations, field studies, applying innovative precise soil/foliar fertigation, and investigation of the postharvest treatment of fresh cut flowers, promoting networking and synergies with producers and associations in Greece and abroad.

Diversity and nodulation effectiveness of rhizobia and mycorrhizal presence in climbing dry beans grown in Prespa lakes plain, Greece.

The Prespa lakes plain is an isolated area where about 1000 ha are seeded to Phaseolus vulgaris L. and Phaseolus coccineus L. Nodulation, arbuscular mycorrhizal fungal (AMF) presence and the genetic diversity of rhizobia were evaluated by 16S-ITS-23S-RFLP patterns and by sequencing. The bean rhizobial population in the region was diverse, despite its geographic isolation. No biogeographic relationships were detected, apart from a Rhizobium tropici-related strain that originated from an acidic soil. No clear pattern was detected in clustering with bean species and all isolates formed nodules with both bean species. Most strains were related to Rhizobium leguminosarum and a number of isolates were falling outside the already characterized species of genus Rhizobium. Application of heavy fertilization has resulted in high soil N and P levels, which most likely reduced nodulation and AMF spore presence. However, considerable AMF root length colonization was found in most of the fields.

Essential oil content and composition, nutrient and mycorrhizal status of some aromatic and medicinal plants of northern Greece.

A field survey was conducted in three northern Greek mountain areas (Chortiatis, Ossa, and Pieria) to investigate the mycorrhizal and nutritional status, and the essential oil content and composition of common medicinal and aromatic plants. A range of values for nutrient status and essential oil contents and composition was established. All plants were found to be mycorrhizal, including Achillea coarctata Poir., Micromeria juliana (L.) Bentham ex Reichenb., and Salvia sclarea L.;. these three are reported as being mycorrhizal for the first time. Arbuscular mycorrhizal fungal root colonization was highest in Pieria, exceeding 80% for all 15 plants sampled, and lower in Chortiatis and Ossa.

Soil microbial community response to hexavalent chromium in planted and unplanted soil.

Theories suggest that rapid microbial growth rates lead to quicker development of metal resistance. We tested these theories by adding hexavalent chromium [Cr(VI)] to soil, sowing Indian mustard (Brassica juncea), and comparing rhizosphere and bulk soil microbial community responses. Four weeks after the initial Cr(VI) application we measured Cr concentration, microbial biomass by fumigation extraction and soil extract ATP, tolerance to Cr and growth rates with tritiated thymidine incorporation, and performed community substrate use analysis with BIOLOG GN plates. Exchangeable Cr(VI) levels were very low, and therefore we assumed the Cr(VI) impact was transient. Microbial biomass was reduced by Cr(VI) addition. Microbial tolerance to Cr(VI) tended to be higher in the Cr-treated rhizosphere soil relative to the non-treated systems, while microorganisms in the Cr-treated bulk soil were less sensitive to Cr(VI) than microorganisms in the non-treated bulk soil. Microbial diversity as measured by population evenness increased with Cr(VI) addition based on a Gini coefficient derived from BIOLOG substrate use patterns. Principal component analysis revealed separation between Cr(VI) treatments, and between rhizosphere and bulk soil treatments. We hypothesize that because of Cr(VI) addition there was indirect selection for fast-growing organisms, alleviation of competition among microbial communities, and increase in Cr tolerance in the rhizosphere due to the faster turnover rates in that environment.