Intracellular reorganization and ionic signaling of the phycomyces stage i sporangiophore in response to gravity and touch

Unicellular zygomycete fungus Phycomyces blakesleeanus exhibits a typical apical growth that depends on a complex interaction of different physiological processes. Sensitivity to the light, wind, barriers, touch and gravity of Phycomyces sporangiophore implicate the existence of the cross-talk between different signaling pathways in the same cell. Touch and gravity in Phycomyces sporangiophore seem to share some common elements of Ca2+ and H+ ion-based signal transduction systems. Apoplastic Ca2+ and H+ ionic fluxes are important for establishing cell polarity in tip growing sporangiophore both in vertical and tilted position. Upon gravistimulation sporangiophores display asymmetric ionic distribution and intracellular reorganization leading to change in the growth pattern

Early flowering species - model plants for studies of ontogenesis in vitro

Chenopodium rubrum L. and Chenopodium murale L. are two annual weed species with different photoperiodic demands. The use of species from the same genus, with a similar type of morphogenesis but with different photoperiodic demands, is valuable for comparative studies of flowering. In addition, being classified as early flowering species, these two species represent model plants suitable for studies of ontogenesis in vitro. This review describes part of our results obtained on these two model plants under the guidance of Professor Ljubinka Ćulafić, starting with early development, such as somatic embryogenesis, followed by photoperiodic and hormonal regulation of flowering, to the photoperiodic control of different stages of ontogenesis

Does overhead irrigation with salt affect growth, yield, and phenolic content of lentil plants?

Overhead irrigation of lentil plants with salt (100 mM NaCl) did not have any significant impact on plant growth, while chlorophyll content and chlorophyll fluorescence parameter Fv/Fm were affected. Under such poor irrigation water quality, the malondialdehyde content in leaves was increased due to the lipid peroxidation of membranes. In seeds, the total phenolic content (TPC) was correlated to their total antioxidant capacity (TAC). High performance liquid chromatography-mass spectrometry (HPLC-MS) detection showed that flavonoids (catechin, epicatechin, rutin, p-coumaric acid, quercetin, kaempferol, gallic acid and resveratrol) appear to be the compounds with the greatest influence on the TAC values. Catechin is the most abundant phenolic compound in lentil seeds. Overhead irrigation with salt reduced the concentration of almost all phenolic compounds analyzed from lentil seed extracts

Antioxidant activity and fluorescence of colored maize (Zea Mays L.) seeds under various temperature conditions

The quality of cereal seeds could be altered by the different temperature conditions. In this study, the influence of temperature on the antioxidant activities and the fluorescence characteristics of various cultivars of colored maize (Zea mays L.) seeds were estimated. For that purpose, the seeds were exposed to different temperatures (25°C (Control), 45°C, and 90°C), for 60 minutes. The antioxidant activities of the various colored seeds have been determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) reagent. Our results showed that a rise in temperature caused an increase in the antioxidant activities in the yellow, light- and dark-red colored seeds. This was more pronounced in the dark-red colored seeds. However, no statistically significant differences were found in the antioxidant activities of the white-colored seeds at the different temperatures. The fluorescence analysis indicates differences in emission spectral parameters among the analyzed seed types and effect of various temperature conditions. Both methods have proven to be useful for monitoring changes caused by temperature treatment of the seeds but could also be applied for characterization and quality control of seeds after different types of treatments

Does overhead irrigation with salt affect growth, yield, and phenolic content of lentil plants?

Overhead irrigation of lentil plants with salt (100 mM NaCl) did not have any significant impact on plant growth, while chlorophyll content and chlorophyll fluorescence parameter F-v/F-m were affected. Under such poor irrigation water quality, the malondialdehyde content in leaves was increased due to the lipid peroxidation of membranes. In seeds, the total phenolic content (TPC) was correlated to their total antioxidant capacity (TAC). High performance liquid chromatography-mass spectrometry (HPLC-MS) detection showed that flavonoids (catechin, epicatechin, rutin, p-coumaric acid, quercetin, kaempferol, gallic acid and resveratrol) appear to be the compounds with the greatest influence on the TAC values. Catechin is the most abundant phenolic compound in lentil seeds. Overhead irrigation with salt reduced the concentration of almost all phenolic compounds analyzed from lentil seed extracts

Effect of drying temperature on antioxidant activity of white and red maize (Zea mays L.) seeds

Maize is the most commonly consumed cereal in the world. Its various compounds are associated with nutraceutical properties and health-promoting benefits. Therefore, maize seeds are considered to be functional food with high antioxidant activities. The drying conditions have a huge impact on maintaining the seed quality. This study aimed to evaluate the effect of temperature on the antioxidant activities of white and red maize (Zea mays L.) cultivars. A drying time of 1 h at a temperature of 45 °C was tested. The antioxidant activity expressed in percentages was evaluated as radical scavenging activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) reagent. The results revealed that the antioxidant activity of the dried white seeds (74.08 %) was not significantly different (p>0.005) with respect to the un-dried seeds used as control (72.6 %). Contrary, drying at 45 °C caused a significant (p<0.005) rise of antioxidant activity in the red-coloured seeds' being 85.95 % and 92.25 % before and after the treatment, respectively. The obtained results show that the antioxidant activity may be a reliable indicator for the estimation of the cereal seeds’ quality, which is useful in the food industry and agriculture

Surface tip-to-base Ca2+ and H+ ionic fluxes are involved in apical growth and graviperception of the Phycomyces stage I sporangiophore

Net fluxes of Ca2+ and H+ ions were measured non-invasively close to the surface of Phycomyces blakesleeanus sporangiophores stage I using ion-selective vibrating microelectrodes. The measurements were performed on a wild type (Wt) and a gravitropic mutant A909 kept in either vertical or tilted orientation. Microelectrodes were positioned 4 mu m from the surface of sporangiophore, and ion fluxes were recorded from the apical (0-20 mu m) and subapical (50-100 mu m) regions. The magnitude and direction of ionic fluxes measured were dependent on the distance from the tip along the growing zone of sporangiophore. Vertically oriented sporangiophores displayed characteristic tip-to-base ion fluxes patterns. Ca2+ and H+ fluxes recorded from apical region of Wt sporangiophores were inward-directed, while ion fluxes from subapical locations occurred in both directions. In contrast to Wt, mutant A909 showed opposite (outward) direction of Ca2+ fluxes and reduced H+ influxes in the apical region. Following gravistimulation, the magnitude and direction of ionic fluxes were altered. Wt sporangiophore exhibited oppositely directed fluxes on the lower (influx) and the upper (efflux) sides of the cell, while mutant A909 did not show such patterns. A variable elongation growth in vertical position and reduced growth rate upon gravistimulation were observed in both strains. The data show that tip-growing sporangiophores exhibit a tip-to-base ion flux pattern which changes characteristically upon gravistimulation in Wt in contrast to the mutant A909 with a strongly reduced gravitropic response

Quantification of the antioxidant activity in salt-stressed tissues

Biochemical methods available for the measurement of antioxidant activity in salt-stressed tissues are reviewed, outlining the most important advantages and shortcomings of the methods. Here we consider commonly used methods for measuring total antioxidant capacity and phenolic content, ABTS and Folin-Ciocalteu's procedure, respectively. Moreover, we presented assays for determination of antioxidant enzymes activities: superoxide dismutase, catalase, and ascorbate peroxidase. This choice of methods enables us to elucidate a full profile of antioxidant activities, evaluating their effectiveness against various reactive oxygen species produced during salt stress

Light-induced transient ion flux responses from maize leaves and their association with leaf growth and photosynthesis

Net fluxes of H+, K+ and Ca2+ ions from maize (Zea mays L.) isolated leaf segments were measured non-invasively using ion-selective vibrating microelectrodes (the MIFE technique). Leaf segments were isolated from the blade base, containing actively elongating cells (basal segments), and from non-growing tip regions (tip segments). Ion fluxes were measured in response to bright white light (2600 mumol m(-2) s(-1)) from either the leaf segments or the underlying mesophyll (after stripping the epidermis). Fluxes measured from the mesophyll showed no significant difference between basal and tip regions. In leaf segments (epidermis attached), light-induced flux kinetics of all ions measured (H+, Ca2+ and K+) were strikingly different between the two regions. It appears that epidermal K+ fluxes are required to drive leaf expansion growth, whereas in the mesophyll light-induced K+ flux changes are likely to play a charge balancing role. Light-stimulated Ca2+ influx was not directly attributable either to leaf photosynthetic performance or to leaf expansion growth. It is concluded that light-induced ion flux changes are associated with both leaf growth and photosynthesis