Influence of storage temperature and time in storage on pigment content of potato (Solanum tuberosum L.)

2005 Fall.Covers not scanned.Includes bibliographical references.Anthocyanins are responsible for different colors in many plant species including potato tubers. They are also one of the important components in human health as antioxidants. Important factors that can affect anthocyanin concentration in potato tubers are storage temperature and the length of storage. The influence of storage temperature and time in storage on tuber anthocyanin concentration was investigated in seven potato genotypes. These genotypes were cultivars All Blue and Yukon Gold as well as VC0967-SR/Y, Purple Majesty (CO9I6S-3P/P), Mountain Rose (CO94183-1R/R), VC1002-3W/Y and CO97232-2R/Y. Tubers of the seven genotypes were stored at 4°C and 10°C for 0, 4, 6, 8, 10, 12, 16, 20 and 24 weeks . Both fresh and freeze-dried samples of the tubers were evaluated for each of the temperature and time treatment combinations. Extractable anthocyanins were obtained in only three genotypes, CO94183-1R/R, CO94165-3P/P and "All Blue", as determined by the UV/Vis Molecular Device Spectra Max Plus 384 spectrophotometer. There was an increase in anthocyanin concentration with increased time in storage for both fresh and freeze-dried samples (P<0.0001). However, tubers stored in the cooler at (4°C) had much higher levels of anthocyanin than those tubers stored at 10°C. Increased levels of anthocyanins in cold-stored tubers are likely associated with the conversion of starch to sugar (so called "cold sweetening") and subsequent conversion to anthocyanins. More anthocyanins were extracted from freeze-dried tuber samples than fresh samples. Both techniques exhibited a similar trend in that an increase in length of time in storage had a similar level of increase in anthocyanin concentration. Extraction of anthocyanins from freeze-dried tissue is more efficient and effective than using fresh tissue for evaluation of anthocyanin concentration in potato tubers

Chitosan and chitosan nanoparticles differentially alleviate salinity stress in Phaseolus vulgaris L. plants

Salinity stress can significantly cause negative impacts on the physiological and biochemical traits of plants and, consequently, a reduction in the yield productivity of crops. Therefore, the current study aimed to investigate the effects of chitosan (Cs) and chitosan nanoparticles (CsNPs) to mitigate salinity stress (i.e., 25, 50, 100, and 200 mM NaCl) and improve pigment fractions, carbohydrates content, ions content, proline, hydrogen peroxide, lipid peroxidation, electrolyte leakage content, and the antioxidant system of Phaseolus vulgaris L. grown in clay–sandy soil. Methacrylic acid was used to synthesize CsNPs, with an average size of 40 ± 2 nm. Salinity stress negatively affected yield traits, pigment fractions, and carbohydrate content. However, in plants grown under salt stress, the application of either Cs or CsNPs significantly improved yield, pigment fractions, carbohydrate content, proline, and the antioxidant system, while these treatments reduced hydrogen peroxide, lipid peroxidation, and electrolyte leakage. The positive effects of CsNPs were shown to be more beneficial than Cs when applied exogenously to plants grown under salt stress. In this context, it could be concluded that CsNPs could be used to mitigate salt stress effects on Phaseolus vulgaris L. plants grown in saline soils

Efficiency of RAPD and SSR markers in assessing genetic diversity in summer onion (Allium cepa L.) genotypes

The genetic diversity assessment of agricultural crops is crucial for breeding programs aimed at enhancing crop yield, resistance to diseases, and adaptation to changing environmental conditions. In the present investigation, a comparative genetic relationship in sixteen onion genotypes was assessed utilizing dominant (RAPD) and co-dominant (SSR) marker systems. Ten RAPD and nine SSR markers showed genetic diversity remarkably and produced 503 and 107 amplicons respectively. Spearman rank correlation was used to compare the different efficiency parameters in two marker systems with respect to sixteen onion genotypes. The genetic relationship based on similarity matrix values between a pair of cultivars was higher for SSR markers than for the RAPD marker system. OPC-04 (RAPD primer) and ACM-004 (SSR primer) witnessed the highest poly-morphic bands along with other polymorphic markers that proved to be useful in grouping onion genotypes. Finally, dendrograms were constructed and compared following the mantel test to find out the genetic diversity among the germplasms. This study will be effective for a selection of efficient primers and suitable marker systems to distinguish the onion genotypes in the future

Effects of Putrescine Application on Peach Fruit during Storage

The peach industry faces serious economic losses because of the short &#8220;green&#8222; life of the fruit at postharvest. In the present study, we investigated the effects of putrescine (PUT) application on the quality characteristics, pattern of ripening, storage behaviour and shelf life of peach fruit during low-temperature storage. The aqueous solution of PUT (0, 1, 2 and 3 mM) was applied to the peach trees at three distinctive stages of fruit growth and development. The fruits, harvested at the commercial stage of maturity, were stored at 1 &#177; 1 &#176;C and 90 &#177; 2% relative humidity for 6 weeks. The data for fruit firmness, total soluble solids (SSC), titratable acidity (TA), ascorbic acid (AsA) content, rate of ethylene production, chilling injury (CI) index and colour perception were collected at harvest and then on a weekly basis throughout the storage period. The results showed that spray application of PUT significantly reduced the incidence of CI and reduced the rates of fruit softening, loss in fruit weight, SSC, TA, AsA content and fading of skin colour during storage, regardless of the doses of PUT applied, or the time of application. However, the positive effects on the quality characteristics of peach fruit, including CI, were more pronounced with the higher doses of PUT, specifically when applied at 2 mM. In conclusion, CI in peach fruit may be substantially alleviated by the spray application of 1&#8211;3 mM PUT during fruit growth without compromising the quality of the fruit for up to 6 weeks in low-temperature storage

Morphological and Biochemical Response of <i>Potatoes</i> to Exogenous Application of ZnO and SiO₂ Nanoparticles in a Water Deficit Environment

A field study was conducted to understand the effectiveness of foliar applications of ZnO-NPs (0, 50, 100 mg L−1) and SiO2-NPs (0, 25, 50 mg L−1) on potato plant growth, morphology, nutrient uptake, oxidative stress, and antioxidative response under drought conditions (i.e., 100% crop evapotranspiration ETc, 75% ETc, and 50% ETc). Results revealed that water deficiency significantly hampered plant growth and biomass production and stimulated oxidative stress in potatoes. However, the exogenous application of ZnO-NPs and SiO2-NPs significantly improved plant growth attributes such as the number of branches, plant height, fresh and dry biomass, leaf area, and leaf area index as compared with untreated plants. The foliar application of ZnO-NPs (i.e., 100 and 50 mg L−1) and SiO2-NPs (50 mg L−1) promoted the mineral ion accumulation in plants grown under water deficiency and thus resulted in higher NPK, Zn2+, Fe2+, and Mn2+ contents. A significant reduction in malondialdehyde (MDA) and hydrogen peroxide (H2O2) was found in plants treated with 100 mg L−1 ZnO followed by 50 mg L−1 SiO2 and 50 mg L−1 ZnO nanoparticles as compared with untreated plants, respectively. Furthermore, the aforesaid treatments resulted in the maximum activity of antioxidant enzymes (i.e., superoxide dismutase SOD, catalase CAT, polyphenol oxidase PPO, and ascorbate peroxidase APX) under water deficit stress. Similarly, the foliar application of ZnO and SiO2 nanoparticles improved nonenzymatic antioxidants such as total flavonoid content (TFC) and total phenolic compounds (TPC) as compared with untreated plants (control). Moreover, plant growth traits were significantly and positively correlated with mineral contents, while they were negatively correlated with MDA and H2O2. ZnO-NPs and SiO2-NPs applications improved biochemical traits, which might lead to enhancements in plant tolerance and improvements in potato growth, productivity, and quality traits under water shortage conditions

Mycorrhizal Effects on Growth and Expressions of Stress-Responsive Genes (aquaporins and SOSs) of Tomato under Salt Stress

Environmentally friendly arbuscular mycorrhizal fungi (AMF) in the soil can alleviate host damage from abiotic stresses, but the underlying mechanisms are unclear. The objective of this study was to analyze the effects of an arbuscular mycorrhizal fungus, Paraglomus occultum, on plant growth, nitrogen balance index, and expressions of salt&nbsp;overly&nbsp;sensitive genes (SOSs), plasma&nbsp;membrane&nbsp;intrinsic&nbsp;protein genes (PIPs), and tonoplast&nbsp;intrinsic&nbsp;protein genes (TIPs) in leaves of tomato (Solanum lycopersicum L. var. Huapiqiu) seedlings grown in 0 and 150 mM NaCl stress. NaCl stress severely inhibited plant growth, but P. occultum inoculation significantly improved plant growth. NaCl stress also suppressed the chlorophyll index, accompanied by an increase in the flavonoid index, whereas inoculation with AMF significantly promoted the chlorophyll index as well as reduced the flavonoid index under NaCl conditions, thus leading to an increase in the nitrogen balance index in inoculated plants. NaCl stress regulated the expression of SlPIP1 and SlPIP2 genes in leaves, and five SlPIPs genes were up-regulated after P. occultum colonization under NaCl stress, along with the down-regulation of only SlPIP1;2. Both NaCl stress and P. occultum inoculation induced diverse expression patterns in SlTIPs, coupled with a greater number of up-regulated TIPs in inoculated versus uninoculated plants under NaCl stress. NaCl stress up-regulated SlSOS2 expressions of mycorrhizal and non-mycorrhizal plants, while P. occultum significantly up-regulated SlSOS1 expressions by 1.13- and 0.45-fold under non-NaCl and NaCl conditions, respectively. It was concluded that P. occultum inoculation enhanced the salt tolerance of the tomato, associated with the nutrient status and stress-responsive gene (aquaporins and SOS1) expressions