Autophagic and phytochemical aspects of color changes in white petals of snapdragon flower during development and senescence.

Color change in petals is a clever strategy to attract more pollinators and one of the attractive features of edible flowers for consumers. Several physiological, phytochemical, and ultrastructural factors are involved in this process. However, this phenomenon is well underexplored in white petals. In this study, we investigated the color changes of the white petals of the snapdragon (Antirrhinum majus 'Legend White') flower from different aspects during development and senescence. In the ultrastructural analysis, both epidermal and mesophyll cells were examined. During flower development, plastid transition and autophagy processes led to the fading of the green color of young petals and the reduction of starch content, chlorophyll, and carotenoids. The piecemeal chlorophagy was observed in the degradation of starch granules. Leucoplasts were converted into autophagosome-like structures and then disappeared. The presence of these structures was evidence of the transformation of the plastid to the vacuole. As the green color faded, phytochemical compounds were synthesized. With partial flower opening and progression of senescence, pH and phenolic compounds were responsible for color changes. The highest amount of phenolic compound was observed after the flower opening stages. However, Phenolic colored compounds or total anthocyanins became colorless under the influence of low pH. The decrease in starch content caused an increase in the lightness parameter, and the petal color changed to pale yellow.

Investigation of the cell structure and organelles during autolytic PCD of Antirrhinum majus "Legend White" petals.

One of the classes of the plant developmental programmed cell death (PCD) is vacuolar cell death or autolysis. The results of the transmission electron microscope (TEM) studies indicated that this type of PCD occurs during the petal senescence of Antirrhinum majus "Legend White" flowers. The major hallmarks of the process related to the ultrastructure of the cells involved chloroplast degradation, vacuolation, chromatin condensation, cell wall swelling, degradation of Golgi apparatus, protoplasmic shrinkage, degradation of the endoplasmic reticulum, nuclear fragmentation, rupture of tonoplast, and plasma membrane. Macroautophagy and microautophagy processes were also clearly observed during vacuole formation. As in yeasts, in the present study, Golgi apparatus became autophagosome-like structures during degradation that had autophagy activity and then disappeared. Our results revealed a type of selective microautophagy, piecemeal microautophagy of the nucleus (PMN), in nuclear degradation during PCD of petals that has not previously been reported in plants. Moreover, vesicular structures, such as paramural and multilamellar bodies, were observed in some stages.

Chitosan nano-biopolymer/Citrus paradisi peel oil delivery system enhanced shelf-life and postharvest quality of cherry tomato.

Grapefruit peel essential oil (CpEO) was loaded on chitosan (Cs) nano-biopolymer by ionic gelation method and its effect on physicochemical properties of cherry tomatoes was evaluated during 18 days of storage at 10 °C. The highest loading capacity and encapsulation efficiency were obtained from the weight ratio of 1:0.25 Cs to oil. TEM, DLS and FTIR were used to characterize the nanoparticles. The release of the oil from the nanoparticles followed the Fickian diffusion model. CpEO-CsNPs-CO and CpEO-CsNPs-RE treatments reduced ethylene production and respiration rate and indicated a significant and promising effect on increasing the level of antioxidant enzymes (CAT and POD), slowing down the loss of ascorbic acid and total phenolic content and consequently, maintaining antioxidant capacity. These treatments prevented a rapid decline in TSS and TA and an increase in lycopene and MDA level, and maintained the firmness, weight, and color of the fruits throughout storage period.

Control of nectarine fruits postharvest fungal rots caused by Botrytis Cinerea and Rhizopus Stolonifer via some essential oils.

Nectarines (Prunus persica L. Bath) are very sensitive fruit to fungal infection. Today, the control of postharvest fruit diseases with essential oils (EOs) has been significantly noticed as a novel trend in biological preservation. In this study, volatile compounds of Cinnamon zeylanicum (CEO), Zataria multiflora (ZEO), and Satureja khuzestanica (SEO) were analyzed by Gas Chromatography-Mass spectroscopy. Also, the in vitro antifungal activities of EOs against Botrytis cinerea and Rhizopus stolonifer were evaluated at different concentrations. The in vivo antifungal activity of these EOs on artificially infected nectarine fruits was also considered. The major components were Thymol (32.68%) and Carvacrol (30.57%) for ZEO, cinnamaldehyde (80.82%) for CEO, and carvacrol (38.43%) for SEO. The application of different concentrations showed a decreasing trend in the fungus radial growth in all EOs. In the in vitro experiments, ZEO and CEO exhibited more significant mycelial inhibition results and reduction of the IC50, MIC and MFC values against Botrytis cinerea and Rhizopus stolonifer, respectively. However, in the in vitro experiments, none of the treatments were capable of completely inhibiting the growth of the fungi. According to the results of this study, ZEO and CEO could reduce the damage caused by these fungi.