Commercial advantages on basil architecture by ultraviolet-B irradiation

Sweet 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

Commercial advantages on basil architecture by ultraviolet-B irradiation

Sweet 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

Ubiquitin Ligase ATL31 Functions in Leaf Senescence in Response to the Balance Between Atmospheric CO2 and Nitrogen Availability in Arabidopsis

Carbon (C) and nitrogen (N) are essential elements for metabolism, and their availability, called the C/N balance, must be tightly coordinated for optimal growth in plants. Previously, we have identified the ubiquitin ligase CNI1/ ATL31 as a novel C/N regulator by screening plants grown on C/N stress medium containing excess sugar and limited N. To elucidate further the effect of C/N balance on plant growth and to determine the physiological function of ATL31, we performed C/N response analysis using an atmospheric CO2 manipulation system. Under conditions of elevated CO2 and sufficient N, plant biomass and total sugar and starch dramatically increased. In contrast, elevated CO2 with limited N did not increase plant biomass but promoted leaf chlorosis, with anthocyanin accumulation and increased senescence-associated gene expression. Similar results were obtained with plants grown in medium containing excess sugar and limited N, suggesting that disruption of the C/N balance affects senescence progression. In ATL31-overexpressing plants, promotion of senescence under disrupted CO2/N conditions was repressed, whereas in the loss-of-function mutant it was enhanced. The ATL31 gene was transcriptionally up-regulated under N deficiency and in senescent leaves, and ATL31 expression was highly correlated with WRKY53 expression, a key regulator of senescence. Furthermore, transient protoplast analysis implicated the direct activation of ATL31 expression by WRKY53, which was in accordance with the results of WRKY53 overexpression experiments. Together, these results demonstrate the importance of C/N balance in leaf senescence and the involvement of ubiquitin ligase ATL31 in the process of senescence in Arabidopsis

Differential Expression of 1-Aminocyclopropane-1-carboxylate Synthase and Oxidase Gene Family in Micro-Tom Tomato Leaves and Roots Under Short Daily UV Radiation

Few studies focussed on the effects of UV radiation on ethylene (ET) production, thus little is known about the changes in the expression of the ET biosynthetic genes and there are no data about roots. Based on our previous results showing reduced ET emission by UV-treated leaves of Micro-Tom tomato plants, the effects of short UV treatments (0.132 and 0.015 W m−2 biologically effective UV-B and UV-A irradiance, respectively, 15 min/day for 11 days) on the gene expression of the ET biosynthetic enzymes, ACC synthase (ACS1-7) and ACC oxidase (ACO1-5), were checked to determine whether UV radiation could cause changes at the transcriptional level and which isoforms were affected. The study regarded also roots to understand whether the invariance of root ET emission might relate to unchanged transcription of the biosynthetic genes or to a balance between up- and down-regulation of different isoforms. Chlorophylls and UV-responsive metabolites were quantified to verify plant healthiness and responsiveness. The general downregulation of ACO isoforms after 8 and 11 days of UV treatment was probably the cause of the reduced foliar ET emission, whilst after 3 days of recovery the similar ET levels agreed with the invariance of ACO transcript levels between control and treated plants. These data strengthen our hypothesis of ACOs as key ET regulators under short mild UV treatments, though, since we focussed on only 50% of the ACS genes, others may be involved in the tomato plant response to UV. Fluctuations of ACS and ACO mRNA were evident in roots, but this did not influence the ET emission of this organ

Urban conditions affect soil characteristics and physiological performance of three evergreen woody species

Physiological studies conducted mainly in metropolitan areas demonstrated that urban environments generate stressful conditions for plants. However, less attention has been paid to plant response to urban conditions in small cities. Here, we evaluated to what extent the health and physiological functions of some Mediterranean urban species [Quercus ilex L., Nerium oleander L. and Pittosporum tobira (Thunb.) W.T. Aiton] were impacted by urban and peri-urban conditions in Pisa (Italy), a small medieval city with narrow streets that impede efficient public transport causing oversized private transport. Experimental period spanned from late-summer to winter in concomitance with the sharp increase in air pollutants. Climate and air quality, soil physical and chemical properties, and plant physiological traits including leaf gas exchanges, chlorophyll fluorescence and leaf pigments were assessed. In soil, the organic carbon affected aggregates and water stability and the concentrations of some micro-elements decreased in winter. Air pollutants impaired leaf gas exchanges and photochemical processes at photosystem II, depending on species, season, and urban conditions. Shrubs were more susceptible than the tree species, highlighting that the latter adapted better to pollutants along an urban-peri-urban transect in Mediterranean environments. This study gives information on the physiological adaptability of some of the most frequent Mediterranean urban species to stressful conditions and demonstrated that, even in a small city, urban conditions influence the physiology and development of vegetation, affecting the plant health status and its ability to provide key ecosystem services