117,422 research outputs found
Commercial advantages on basil architecture by ultraviolet-B irradiation
No full textSweet basil (Ocimum basilicum L.) is one of the most important herbs widely used for its medicinal properties and as food ingredient. The marketing of this product highlights the problem that these plants have long and slender stems, which are easy to break off and thus making difficult their market distribution. In this work, two cultivars of basil (Genovese and Profumo) at the adequate development stage for sale were used. We evaluated the effect of supplemental ultraviolet (UV)-B irradiation (15 W m-2; 3 h day-1) on plant growth and market quality. Both cultivars of basil plants under UV-B irradiation resulted in increased leaf size and biomass, and decreased shoot length in comparison to that of under control growth conditions. These results indicate that the application of UV-B irradiation beneficially influenced plant architecture in basil improving their greenhouse production for fresh market
Effects of combined biochar and vermicompost solution on leachate characterization and nitrogen balance from a greenhouse tomato (Solanum lycopersicum) cultivation soil
No full textBoth biochar (B) and vermicompost (V) can provide the soil with soluble organic matter. We evaluated the effect of B in reducing nitrate and dissolved organic carbon (DOC) losses from soil via leaching together with the effect of B combined with V solution (vermiwash) in increasing the efficiency of plant nitrogen. Tomato plants (Solanum lycopersicum L.) were cultivated in a greenhouse with soil under three different amendments (B, V and a mix BV). B was applied at a rate of 2% w/w corresponding to 34 t ha−1. V was applied at 25 mg per plant through fertigation. Leachate and soil were monitored in terms of nitrates and DOC throughout the trial (120 days), and plants and fruits were monitored in terms of nitrogen balance index (NBI) and dry matter biomass. B and BV significantly decreased NO3–_N content in the leachate in all recovered times by 66.8% and 71.3%, respectively. In contrast, the absence of biochar in the V treatment led to a 38.1% increase in NO3–_N concentration. Similar results were found for DOC content. The dry biomass of plants increased in B and BV treatments by 19.5 and 28.7%, respectively. The dry biomass of tomato fruits was enhanced by 18.5, 12.1, and 37% in V, B and BV treatments, respectively. Synergisms were found between the char material and complex organic compounds derived from the vermicompost process in terms of safeguarding the quality of the soil, the underground water, and the sustainability of crops. © 2021 Taylor & Francis Group, LLC
Carbohydrate metabolism in germinating caryopses of Oryza sativa L. exposed to prolonged anoxia
No full textAnoxia tolerance can be evaluated not only in terms of growth or survival of plant organs during oxygen deprivation, but also in relation to carbohydrate utilization in the context of a well-modulated fermentative metabolism. Rice (Oryza spp.) is unique among cereals, in that it has the
distinctive ability to germinate under complete anaerobiosis by using the starchy reserves in its seeds to fuel the anaerobic metabolism. The aim of the present study was to evaluate the ability of germinating rice seedlings to survive a longterm oxygen deficiency [40 days after sowing DAS)] and the effects on sugar metabolism, focusing on starch degradation as well as soluble sugars transport and storage under anoxia. No significant decline in vitality occurred until 30 DAS though no recovery was detected following longer anoxic treatments. Growth arrest was observed following anoxic treatments longer that 20 DAS, in concomitance with considerably lower ethanol production. Amylolytic activity in embryos and endosperms had similar responses to anoxia, reaching maximum content 30 days after the onset of stress, following which the levels declined for the remainder of the experiment. Under anoxia, average amylolytic activity was twofold higher in embryos than endosperms. Efficient starch degradation was observed in rice under anoxia at the onset of the treatment but it decreased over time and did not lead to a complete depletion. Our analysis of α-amylase activity did not support the hypothesis that starch degradation plays a critical role in explaining differences in vitality and coleoptile growth under prolonged oxygen deprivation
Freeze tolerance and physiological changes during cold acclimation of giant reed (Arundo donax L.)
No full textArundo donax L. (Poaceae), giant reed, is a rhizomatous shrubby grass that is cultivated in subtropical and warm temperate regions for a multitude of uses. Recently, it has been identified as a leading sustainable, non-food crop for lignocellulosic biofuels due to its low ecological and agronomic demands. Lack of cold hardiness may limit its diffusion into colder areas of the transition zone. The objectives of this study were to (i) quantify freeze tolerance (LT50) of cold-acclimated and non-acclimated Arundo donax L. plants using reproducible, controlled environment conditions, (ii) determine the effect of prolonged exposure to freeze stress on tolerance by keeping plants at a constant, sublethal temperature and (iii) study the relationship of non-structural carbohydrates (total soluble sugars, glucose, fructose and sucrose) and proline accumulation with cold hardiness. In vitro-propagated plants of the Honduran and Hungarian ecotypes of Arundo donax L. were chosen for this study. Cold acclimation treatment was imposed for 1 week using a controlled environment chamber set at 10°C and with a 12-h photoperiod of 200 lmol m2 s1 photosynthetically active radiation. Freeze tolerance ranged from 12,8°C (Honduran) to 16,4°C (Hungarian ecotype). In all the organs analysed, total soluble sugars significantly increased during cold acclimation, with concentrations between 18- and 47-fold higher
than in non-acclimated plants. The higher concentrations of sugars and proline in cold-acclimated plants were positively associated with enhanced giant reed freeze tolerance (29°C lower). Our results confirm that during cold acclimation, metabolic changes related to increased freezing tolerance occur in giant reed
Effect of Ethanol on the Expression of Two Fructokinases in Rice Seedlings
No full textGermination of rice (Oryza sativa L.) caryopses in the presence of exogenous ethanol (the end-product of alcoholic fermentation under anoxia) results in a decrease of coleoptile and root growth. The ethanol level measured in rice caryopses incubated in 50 mM exogenous ethanol under aerobic conditions was similar to that in caryopses incubated under anoxia. Application of 50 mM ethanol under aerobic conditions induced the production of OsFK2, a fructokinase isoform having a central role in the response of rice to anoxia. The induction of OsFK2 by ethanol was organ-specific: OsFK2 was produced mainly in the embryo and partially in the coleoptile, but not in root tissues. The results of this research suggest that rice can sense ethanol under anoxia and shows a molecular response to oxygen deprivation
Beneficial Effects of Trichoderma harzianum combined with fructans on tomato plant growth.
No full textArundo donax L. response to low oxygen stress
No full textProduction of nonfood species is promoted to marginal, degraded lands abandoned by mainstream agricultural, where extremes in water availability (droughts and floods) have increased frequency and intensity and account for severe reductions in yields. A metabolic analysis of anoxic and hypoxic stress response was performed in a time-course experiment on Arundo donax L., a perennial rhizomatous grass identified as a leading candidate crop for lignocellulosic feedstock in the Mediterranean environment, due to its positive energy balance, and low ecological/agro-management demands. Tolerance to oxygen deprivation was determined after reoxygenation. Giant reed displayed time-dependent reduction in absolute growth and alterations in the derived physiological attributes under low oxygen stress. Our results show that although giant reed's responses to anoxic and hypoxic treatments share a common energy crisis related to the anaerobic metabolism, they differ in terms of ADH activity and related gene response. In leaves and roots tissues, the expression of this anaerobic gene was strongly enhanced under anoxia, whereas the ADH expression under submergence condition was relatively low. The activity profiles of ADH were not completely reflected in the expression patterns in either tissue. A high basal activity of the enzyme was recorded in both leaves and roots in normoxic tissues. In leaves, the treatments did not significantly affect ADH activity, remaining relatively stables at low levels during the time-course experiment. A different pattern of ADH was observed in roots, with a stronger, albeit transient, induction in both oxygen deficiency treatments
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