查看更多>>摘要：? 2022The purpose of the present work was to provide novel knowledge about the mechanisms underlying the preservation of strawberry fruit by 1-methylcyclopropene (1-MCP) treatment during storage. Harvest-ripe strawberries were treated with 1-MCP for ten hours at 22 °C and then stored for ten days at 4 °C and two days at 20 °C. 1-MCP treatment significantly delayed the loss of fruit firmness and the accumulation of anthocyanins during storage, whereas sustained pH, titratable acidity, total sugars, and phenolic compounds values. 1-MCP treatment reduced the in vitro growth of fungal pathogens Botrytis cinerea and Rhizopus stolonifer when using isolated fruit cell walls as only carbon source. Also, 1-MCP treatment was effective in delaying the appearance of fungal lesions and reducing their severity in comparison with non-treated fruit. 1-MCP treated fruit showed higher amounts of ionically bounded pectins and hemicellulose fractions than controls. Treated fruit showed an increase of pectin methylesterase activity, and the inhibition of polygalacturonase, β-galactosidase, α-arabinofuranosidase, and β-xylosidase activities. 1-MCP application modified the expression of relevant genes related to strawberry fruit firmness, increasing the FaPME1 and FaXTH1 mRNA abundance and down-regulating FaPG1, FaPLC, and FaXTH2 expression. Treatment delayed the in vitro cell wall swelling and the collapse of the hemicellulose-cellulose mesh during storage. The effect of 1-MCP on the cell wall composition and its accessibility to necrotrophic pathogens through an up-regulation of endogenous pectin methylesterases and xyloglucan transglycosylases and a down-regulation of lyases and hydrolases is the first report in commercial-ripe strawberries. Moreover, the effect of 1-MCP treatment combined with a dip in a CaCl2 solution on the firmness of strawberry fruit was evaluated. As a result, 1-MCP/CaCl2 treatment rendered significantly firmer fruit when compared with control, and also with 1-MCP, or CaCl2 individual applications.
查看更多>>摘要：? 2022 Elsevier B.V.The palm Euterpe edulis presents primary meristematic growth without sprouting at the base, which prevents conventional vegetative propagation. Here, we assessed the effect of the herbicides 2,4-D and picloram on somatic embryogenesis as an alternative means for propagating and in vitro conservation of pro-embryogenic cultures of E. edulis, as their seeds are recalcitrant. Embryos could be effectively induced with 2,4-D (159.42 μmol L?1) and PIC (300 μmol L?1), totaling 44.33 and 76.33 embryos, respectively. Moreover, proembryos, embryogenic clusters, and somatic embryos were clearly visible. Embryogenic and meristematic cells presented marked staining of the cytoplasm, spherical shape of the cells and nucleus, and rapidly dividing nucleoli. Maturation of explants induced with 2,4-D and PIC was improved by adding 2iP (12.3 μmol L?1), NAA (0.6 μmol L?1), and AC (0.3 g L?1). During germination, BAP (1 μmol L?1) and GA3 (0.5 μmol L?1) promoted primary root protrusion and emergence of the shoot. In summary, PIC (300 μmol L?1) is suggested for embryogenic induction of E. edulis calli, and medium containing 2iP, NAA, and AC is suggested for maturation. Finally, medium containing BAP and GA3 without an auxin pulse favors the conversion of E. edulis somatic embryos into plants.
查看更多>>摘要：? 2022To simulate a typical market-oriented cultivation in laboratory, plants of basil (Ocimum basilicum L.) were grown from seedling to flowering stages in a new-concept microcosm device that enables roots and aerial parts to grow as under real crop conditions. To test the device efficacy, two microcosms were used with the same lighting architecture, temperature and photoperiodic conditions and with two different light spectra, white (W) or blue-red (BR), displaying a similar spectral power in the blue region. Plant growth, biomass yield, photosynthetic efficiency and nutrient uptake were determined. An innovative analytical approach for secondary metabolic profile was also developed to determine basil quality. The plants grew vigorous and healthy for the whole cultivation period and under both the lighting regimes, giving a biomass yield similar to those of basil grown under conventional greenhouse and field conditions. The two lighting regimes differently affected plant growth and yield, with the BR light, that was characterized by a higher photosynthetic photon flux density (PPFD), associated to higher plants, earlier flowering and greater yield. In the average, fresh and dry aerial biomasses per plant were about 250 g and 41 g under BR and about 114 g and 9 g under W light. Higher concentrations of major nutrients were detected in plants under W light, thus indicating that yield levels and major nutrient concentrations are not necessarily related to each other. Similar Fv/Fm (0.76–0.78) and ETR values were observed under the two light regimes, possibly indicating that plants under long lasting cultivation can adapt to different light regimes to reach similar photosynthetic efficiency levels. Different secondary metabolic profiles were detected in tissues sampled at the end of cultivation period and previously unreported profiles for basil were also recorded, possibly indicating that the extent of plant growth affects secondary metabolism in basil, in addition to light spectrum and PPFD level. This is the first report of basil grown under microcosm conditions from seedlings to adult plants. Our results indicate that the microcosm based-technology is effective in simulating a typical market-oriented cultivation and that long lasting cultivation emphasizes the effects of different environmental conditions on plant growth and metabolism.
查看更多>>摘要：? 2022Apart from some works dealing with potato tuber growth and nutritional composition in response to water supply, no study on the effects of irrigation water saving strategies has been found in the literature. This study aimed to investigate the effects of four irrigation regimes: I0 dry control, I1 irrigation during the whole cycle, I2 irrigation from tuber initiation up to 50% of tuber growth, I3 irrigation from 50% of tuber growth to the end of tuber growth on tubers growth and nutritional composition (dry matter, starch, reducing sugars, protein, ash) of two potato cultivars in two planting dates. Irrigating from tuber initiation up to 50% of tuber growth compared to irrigation throughout the whole cycle, did not substantially modify either the tuber dry weight or the sink/source ratio, but did improve the nutritional composition of tubers through higher dry matter and starch contents and comparable values of reducing sugars, proteins and ashes; on the contrary, irrigation from 50% of tuber growth to the end of tuber growth, led to similar results to dry control. The two cultivars behaved similarly with respect to the water regime. In conclusion if the water needs of the crop cannot be met during the entire crop cycle, it is more convenient for tuber growth and nutritional composition to schedule irrigation from tuber initiation up to 50% of tuber growth rather than from 50% of tuber growth to the end of tuber growth.
查看更多>>摘要：? 2022 Elsevier B.V.Citrus phylogeny is currently based on genome analysis using molecular markers and sequencing. The 7 pure genetic groups that gave rise to all cultivated citrus underlie the diversity of citrus accessions originating from Asia. However, there are wild citrus forms whose phylogenetic position is unknown, such as mountain citron (Citrus halimii B.C. Stone) that was discovered in Malaysia in the early 1970s. We sought to elucidate its status by determining its genetic profile with 30 SSR and InDel markers distributed on the 9 chromosomes of the citrus reference genome as compared to those of the 7 pure genetic groups represented by 4 or 5 varieties each. The genetic study was supplemented by a comparison of the composition of essential oils obtained by fruit peel and leaf hydrodistillation to those of the citrus fruits used for genotyping. The genetic study demonstrated that C. halimii is not an interspecific hybrid (low heterozygosity) but rather a true species that shares a common ancestor with kumquats (Fortunella sp.), which would have evolved separately. The fruit aromatic profiles confirmed this kumquat/mountain citron relationship but also highlighted the uniqueness of C. halimii due to the presence of high proportions of compounds that have never been observed in other citrus fruits, such as germacrene D-8-one (accounting for 8.7% of the leaf essential oil).
查看更多>>摘要：? 2022 Elsevier B.V.To obtain new insights into the mechanisms through which melatonin reduces photoinhibition in cucumber seedlings during chilling, we investigated its effects on the Calvin-Benson cycle. Photoinhibition due to chilling was significantly reduced by prior irrigation with a 200 μM melatonin solution. This was evidenced by reduced declines in the quantum yield of photochemical energy conversion in PS II [Φ(PSⅡ)], in the rate of electron transport through PSII [Je(PSII)] and in the electron flux in the PCR cycle [Je(PCR)], and an increase in the PSII excitation pressure (1-qP). The reasons for this can be explained as: (1) melatonin upregulates the expressions of CsrbcL and CsrbcS, and lessens the decrease in Rubisco content induced by chilling; (2) melatonin upregulates the expression of CsRCA, increases the content of Rubisco activase (RCA), and promotes the transformation of Rubisco from the inactive state to the active state, thereby increasing the carboxylation efficiency of Rubp and helping maintain normal rates of CO2 fixation; and (3) melatonin upregulates the expressions of key genes in the Rubp regeneration process to help maintain the regeneration of Rubp required for CO2 fixation, and thus the normal operation of the Calvin-Benson cycle. This study provides new evidence that suggests melatonin reduces photoinhibition during chilling by regulating the Calvin-Benson cycle.
查看更多>>摘要：? 2022Sweet osmanthus (Osmanthus fragrans) flowers, as a food flavor additive, are rich in carotenoids, the majority of which are cyclized carotenoids. Lycopene β- and ε-cyclases (LCYB and LCYE, respectively) catalyze the cyclization of the open ends of acyclic lycopene and manipulate the metabolic flux into different downstream branches. Although both LCYB and LCYE have been fully characterized in many plants, little information is available concerning the functions of sweet osmanthus LCYB and LCYE in carotenoid biosynthesis. In this study, we cloned two lycopene cyclase genes OfLCYB and OfLCYE in sweet osmanthus. The expression levels of OfLCYB in the petals gradually increased during flower opening, having a significant positive correlation with total carotenoid contents in each sweet osmanthus cultivar. Pigment complementation assay in Escherichia coli demonstrated that OfLCYB could efficiently β-cyclize both ends of lycopene to produce β-carotene (β,β-carotene), while OfLCYE was able to catalyze the formation of ε-carotene (ε,ε-carotene) at both ends of lycopene. The characterization of LCYB and LCYE from sweet osmanthus drives the first bifurcation step toward β-carotene and α-carotene. Our results will lay theoretical foundation for future metabolic engineering of carotenoid biosynthesis and accumulation in sweet osmanthus flowers.
查看更多>>摘要：? 2022Jojoba (Simmondsia chinensis) is an emerging industrial oil crop cultivated in desert dry land. Jojoba is sensitive to cold stress, which hinders its domestication in the arid areas of temperate climate regions. Here, the effects of cold acclimation on physiological parameters and gene expression in jojoba leaves were analyzed. The tolerance to cold stress in cold-acclimated jojoba seedlings was enhanced as revealed by delayed fluorescence and photosynthetic parameter measurement. The expression levels of 7520 genes were changed significantly after cold acclimation, and these genes were related to multiple biological processes including the stability of photosynthetic machinery, the enhancement of ROS scavenging ability, and protein folding and RNA processing. A total of 144 miRNAs were identified in jojoba, including 133 conserved miRNAs and 11 species-specific miRNAs, and 106 targets with high confidence of miRNA were identified by degradome sequencing, including 18 novel targets of the conserved miRNAs. Forty-two miRNAs were differentially expressed in jojoba under cold acclimation, and these miRNAs were involved in cold acclimation by negatively regulating their targets. Integrated analysis revealed that multiple gene modules might play central roles in the transcriptional regulatory networks underlying cold acclimation in jojoba, in which the ICE1-CBF-SFR6 pathway activated stress response and plant defense, miR398-CSD1/2 and miR396-glutaredoxin regulated ROS homeostasis, and miR167-GDC1 modulated the protection of photosynthetic machinery. Our study will promote understanding of the molecular mechanism of cold acclimation and provide gene markers for the genetic breeding of jojoba for improving cold stress tolerance.
Cecon P.R.Penso G.A.Serafini G.A.D.Magalhaes dos Santos C.E....
8页
查看更多>>摘要：? 2022The mass and diameter traits of peach fruits are important parameters to define fruit quality, harvest planning, and management of peach production through the estimation of fresh mass. However, currently, fruit mass estimation methods are based on conventional destructive analyzes which, as they are invasive measurements, can take considerable time, in addition to being costly. Thus, this work aimed to use Artificial Neural Networks in the prediction of the fresh mass of peach fruits as an alternative to the destructive method. Fruits of the peach cultivars, 'Tropic Beauty' (G1), 'BRS Kampai' (G2), and 'BRS Rubimel' (G3) were used in the 2017 and 2018 harvests, and the cultivars (G1) and (G2) were used in the 2019 harvest. Fruits were individually measured for fresh mass (FM) (dependent variable), and suture diameter (SD), equatorial diameter (ED), fruit height (FH) (independent variables). Multiple linear regression analysis (R-MLM) and multilayer perceptron artificial neural network (ANN-MLP) were performed, involving the set of dependent variables SD, ED, and FH, all expressed as a function of the independent variable FM. In all scenarios, we observed that ANN_MLP was more effective than R-MLM in predicting FM. The best ANN-MLP was used to predict the mean peach fruit yield of the genotypes and also for their combinations in the 2018 and 2019 harvests. The presence of high values of R2 in the validation sample indicates that the trained network is efficient and has generalization power to predict FM in all situations evaluated. The use of neural networks to predict the fresh mass (FM) of the peach fruit is an alternative to conventional destructive analyzes and the chance to use the same neural network topology in consecutive harvests will allow the collection of data directly in the field, reducing the analysis time and costs.
查看更多>>摘要：? 2022 Elsevier B.V.The recent introduction of new blush pear cultivars has gained increasing consumer interest. The purpose of this study was to investigate the influence of different protective netting shade factors on environmental conditions, fruit growth, vegetative growth, blush colour, blush coverage, fruit quality and yield of the Australian blush pear cultivar 'ANP-0118′. Three nets of varying shade factors (30, 50 and 80%) were assigned to experimental plots, in addition to unnetted plots. All netting used was black in colour. Photosynthetically active radiation (PAR) penetration near sample fruit was assessed and blush colour parameters, fruit diameter and shoot length were monitored weekly. Whole trees were harvested and measured for fruit weight and blush coverage with a fruit grader. Fruit was assessed manually for flesh firmness and soluble solids concentration. Fruit and shoot growth were negatively and positively affected by shade factor, respectively. Overall, increasing shade factor was detrimental to fruit size, blush redness, blush coverage and soluble solids concentration but did not affect flesh firmness. Unnetted fruit achieved highest PAR exposure, and consequently expressed highest blush redness and blush coverage. Yield was similar in unnetted and 30% shade factor plots. The results of this study suggest that the use of shading nets should be limited in order to avoid unfavourable effects on key quality traits in Australian blush pears, yet further exploration into the influence of lower shade factor nets in combination with reflective mulch and biostimulants would be beneficial to the industry.
NSTL
Elsevier