Physiological characteristics, growth, and biomass production of rainfed and irrigated bell pepper [ Capsicum annuum L. var. anuum (Grossum Group) `Quadrato d'Asti'] plants were measured in the semiarid conditions of a Mediterranean summer to determine if drought stress effects are transient and do not affect plant growth and crop yield or are persistent and adversely affect plant growth and crop yield. A low midday leaf water potential indicated the occurrence of transient drought stress episodes in rainfed plants during the first 2 months of the study. Later on, predawn water potential also increased, indicating a persistent drought stress condition despite the occurrence of some rainfall. Photosynthesis was reduced when stress conditions developed, but the reduction was transient and limited to the central part of the day during the first 2 months. As plants aged, however, the impact of drought stress on photosynthesis was not relieved during the overnight recovery period. Stomatal conductance was reduced both during transient and permanent stress conditions while CO 2 transfer conductance (i.e., conductance to CO 2 inside the leaf) was only reduced when photosynthesis inhibition was unrecoverable. However, chloroplast CO 2 concentration was higher in rainfed than in irrigated leaves indicating that CO 2 availability was not limiting photosynthesis. Nonphotochemical quenching of fluorescence increased significantly in rainfed leaves exposed to permanent stress indicating the likely impairment of ATP synthesis. Transient inhibition of photosynthesis did not significantly affect leaf area index and biomass production, but growth was significantly reduced when photosynthesis was permanently inhibited. Fruit dry weight was even higher in rainfed plants compared to irrigated plants until drought stress and photosynthesis reduction became permanent. It is suggested that bell pepper growth without supplemental irrigation over the first part of the vegetative cycle does not impair plant growth and may even be useful to improve yield of early fruit.
1 January 2002 in The Journal of Horticultural Science and Biotechnology
This field experiment was carried out to investigate the physiological changes following water stress in bell pepper plants and their consequences on fruit yield. Bell pepper plants were grown under irrigated and rainfed conditions. Water availability to plants was assessed by measurements of leaf water potentials. Growth was determined by measuring plant (above-ground) and fruit dry-mass accumulation. Solar radiation intercepted by the crop was measured with a linear net radiometer. Leaf protein content and ion accumulation in leaves and fruits were biochemically determined. Leaf photosynthesis and stomatal conductance were measured and mesophyll conductance was estimated in vivo during the crop cycle under field conditions using a portable gas analyser. The quantum yields of the two photosystems were estimated by measurements of chlorophyll fluorescence and absorbance (at 830 nm), in rapid succession. Dry-mass accumulation in above-ground plant organs, gas-exchange characteristics, leaf water potentials, and intercepted solar radiation were lower in rainfed plants than in the irrigated control. Leaf ion and protein concentrations were higher in rainfed than in irrigated plants, while ion accumulation in fruits did not change between treatments. The correlation between the quantum yield of PSI and PSII was similar in irrigated and rainfed plants and did not change even under severe water stress. This experiment showed that photosynthetic limitations in plants growing in the field and subjected to moderate stress conditions were mainly due to decreasing stomatal conductance. In rainfed conditions leaf photosynthesis was also impaired by the reduction of mesophyll conductance, as water stress became severe. The photochemical efficiency of bell pepper leaves was however resistant to drought stress. Photosynthetic limitation was sufficient to reduce plant growth, fruit yield and fruit marketability. This indicates that irrigation is necessary to optimize bell pepper production, and that deficit irrigation may postpone the decline in gas exchange and plant growth as soil becomes dry.
In 2018 there were over 1.8 million new cases worldwide of colorectal cancer and relapses after clinical treatments. Many studies ascribe the risk of the appearance of this cancer to the Western life style : a sedentary life, obesity, and low -fiber, high -fat diets can promote the onset of disease. Several studies have shown supplement phytochemicals to have an inhibiting effect on the growth of various cancers through the activation of apoptosis. Our goal was to prove the effectiveness of a natural compound in the combined therapy of colorectal cancer. Trigno M supplement was an optimal candidate as anticancer product for its high concentrations of phenolic acids, flavonoids and anthocyanins. Our work showed the antitumor activity of Trigno M, extract of Prunus spinosa drupes combined with the nutraceutical activator complex (NAC), in 2D, 3D and in vivo colorectal cancer models. The cellular model we used both in vitro and in vivo was the HCT116 cell line, particularly suitable for engraftment after inoculation in mice. Trigno M inhibited the growth and colony formation of HCT116 cells (35%) as compared to the chemotherapy treatment with 5-fluorouracil (80%) used in clinical therapy. The reduction of the morphological dimensions in the spheroid cells after Trigno M, was compared with 5-fluorouracil demonstrating the efficacy of the Trigno M compound also in 3D models. Flow cytometric analysis on 3D cells showed a significant increase in the apoptotic cell fraction after Trigno M treatment (44.8%) and a low level of necrotic fraction (6.7%) as compared with control cells. Trigno M and 5-fluorouracil induced the apoptosis in a comparable percentage. Monotherapy with Trigno M in severely immunodeficient mice, carrying colon rectal cancer xenografts, significantly reduced tumor growth. The histopatological analysis of the ectopic tumors showed a lower level of necrosis after Trigno M treatment compared with the control. We conclude that Trigno M is well tolerated by mice, delays colorectal cancer growth in these animals and should be weighed up for integration of the current multi-drug protocols in the treatment of colon carcinoma.
The aim of this work was to demonstrate that a natural compound, not-toxic to normal cells, has cytotoxic and sensitizing effects on carcinoma cells, with the final goal of combining it with chemotherapeutic drugs to reduce the overall dose. Prunus spinosa Trigno ecotype (PsT) drupe extract with a nutraceutical activator complex (NAC) made of amino acids, vitamins and mineral salt blends, has shown in vitro anticancer activity. The cytotoxic effect of (PsT + NAC)® has been evaluated on human cancer cells, with an initial screening with colorectal, uterine cervical, and bronchoalveolar cells, and a subsequent focus on colon carcinoma cells HCT116 and SW480. The viability reduction of HCT116 and SW480 after treatment with (PsT 10 mg/mL + NAC)® was about 40% (p < 0.05), compared to control cells. The cell’s survival reduction was ineffective when the drug vehicle (NAC) was replaced with a phosphate buffer saline (PBS) or physiological solution (PS). The flow cytometry evaluation of cancer cells’ mitochondrial membrane potential showed an increase of 20% depolarized mitochondria. Cell cycle analysis showed a sub G1 (Gap 1 phase) peak appearance (HCT116: 35.1%; SW480: 11.6%), indicating apoptotic cell death induction that was confirmed by Annexin V assay (HCT116: 86%; SW480: 96%). Normal cells were not altered by (PsT + NAC)® treatments.
Food production from agriculture depends on irrigation, mainly in poor rainfall zones, such as the Mediterranean region. Chicory is an important food crop component of the Mediterranean diet. Considering the increasing incidence of drought due to climate change, this study was carried out in order to investigate the effect of moderate drought stress on photosynthesis, leaf gaseous exchange, growth, and tocol and carotenoid composition of chicory under field conditions. Chicory was subjected to rainfed condition stress in a randomized block design. At 50 days of treatment, drought stress caused about 48% reduction in dry matter, 30% in leaf relative water content, and about 25% in photosynthetic rate and stomatal conductance, whereas mesophyll conductance was not affected. A strong relationship between photosynthetic rates and stomatal conductance was observed. In the rainfed chicory, at the end of treatment, an increase (about 20%) in carotenoid and tocopherol content was found, thus, giving further insight into the positive effect of moderate drought stress on these compounds. This finding suggests that under proper rainfed conditions, it is possible to increase and save the quality of dry chicory, although yield loss occurs.