Content In Broccoli Research Articles

Impact of Different Technologies and Methods to Increase the Shelf Life and Maintain the Sulforaphane Content in Broccoli: A Review

Broccoli, a nutrient-rich vegetable known for its sulforaphane content and health benefits, faces challenges related to its short shelf life and susceptibility to spoilage. This study explores various techniques to maintain sulforaphane content and extend broccoli's shelf life. Freezing, although effective for long-term preservation, involves blanching that inactivates myrosinase, preventing sulforaphane formation. Cold storage at 4-5°C slows respiration and senescence, extending shelf life up to 14 days while preserving bioactive compounds. Modified atmosphere packaging (MAP) enhances shelf life by altering the package atmosphere, with active packaging using 15% CO2 and 7.5% O2 at 0°C proving particularly effective in reducing bacterial growth and preserving quality. Light exposure, especially with yellow LED lights and moderate UV treatment, retains high levels of glucosinolates and phenolic compounds. Irradiation effectively eliminates pathogens and preserves visual quality, with gamma irradiation slowing the oxidation of phenols and ascorbic acid, although further research is needed on its sensory and nutritional effects. High-pressure processing (HPP), a non-thermal method, significantly boosts sulforaphane bioactivity by converting glucosinolates at pressures up to 600 MPa, despite challenges such as high costs and operational safety, and prevents microbial growth, extending shelf life while maintaining nutritional quality. Additionally, techniques like steaming for optimal durations, microwaving at high power for short times, and stir-frying help preserve sulforaphane content during cooking. Preharvest chemical treatments like chitosan and calcium also enhance broccoli's defence mechanisms and bioactive compound levels. Overall, these methods offer a comprehensive approach to preserving sulforaphane content and extending broccoli's shelf life, providing valuable insights to enhance the storage, quality, and health benefits of broccoli for consumers.

Can LED Lighting Be a Sustainable Solution for Producing Nutritionally Valuable Microgreens?

With its quality, intensity, and photoperiod, light is a decisive abiotic factor that directly influences plant biomass and the accumulation of specialized metabolites (SMs). Photosynthetically active radiation (PAR) has significant effects on primary and secondary plant metabolism and thus influences the morphological characteristics of plants and their antioxidant systems. The aim of this study was to investigate the effects of blue, red, and a 50:50 combination of blue and red LED lighting on the SM content in broccoli, mustard, and garden cress microgreens grown in an indoor farm using the zero-acreage farming technique (ZFarming). This research aims to provide valuable insights into the optimization of light spectra to improve the nutritional quality of microgreens, with a focus on sustainable and space-saving cultivation methods. After eight days, the samples were cut in the cotyledon phenophase and analyzed in a fresh state. The microgreens grown under the blue spectrum LED lighting had the highest content of ascorbic acid (112.70 mg·100 g fw−1), total phenolics (412.39 mg GAE·100 g fw−1), and the highest antioxidant capacity (2443.62 µmol TE·L−1). The results show that the highest content of SMs in all the studied microgreens species was accumulated under the blue spectrum LED lighting. This study underlines the favorable influence of the blue spectrum (400–500 nm) on the nutrient content, especially the enhancement of SMs, in the microgreens investigated. Furthermore, the use of supplemental LED lighting proves to be a sustainable and effective means of producing microgreens with superior nutritional properties through the innovative practice of the zero-acreage farming technique.

Quantification and Diversity Analyses of Glucosinolates in 191 Broccoli Genotypes Highlight Valuable Genetic Resources for Molecular Breeding

Glucosinolates (GSLs), crucial secondary metabolites in cruciferous vegetables, hydrolyze upon consumption or mechanical damage, forming bioactive compounds with anti-cancer properties, such as glucoraphanin (GRA). Among cruciferous vegetables, broccoli stands out for its high GSL content, which varies significantly among different genotypes. This study aimed to characterize and quantify glucosinolate compounds in broccoli using LC-HRMS2 and UPLC. We identified thirteen GSLs in 191 broccoli genotypes, including seven aliphatic, five indole, and one aromatic glucosinolate. The GSL content in these genotypes ranged from 0.1705 to 5.8174 mg/g (DW). We also explored GSL diversity and content in seven developmental organs, finding high diversity and content in seedling roots and florets. Notably, genotype No. 300 had the highest GSL content (5.8174 mg/g, DW) and GRA (3.1545 mg/g, DW), along with a larger flower bulb diameter (13.4 cm) and a shorter growth stage (11 days), demonstrating its potential for breeding GRA-rich broccoli. To our knowledge, this study encompasses the largest number of broccoli genotypes to date, broadening our understanding of GSLs’ diversity and content in broccoli. These findings may provide valuable resources for future breeding or the commercial cultivation of GRA-rich broccoli.

Effect of ZnO Nanoparticles on the Content of Sulforaphane in Broccoli Plant

The experiment was carried out during the agricultural season 2020-2021 and included two laboratory experiments. The first was carried out in the laboratories of the Department of Chemistry Sciences / College of Education for Pure Sciences / the University of Diyala, It included the preparation of nano-zinc oxide by a deposition method, and the second field was carried out in Baquba nursery / Diyala Agriculture Directorate. The addition of zinc oxide included nanoparticles at concentrations of 75 and 150 mg. L-1 to the nutrient solution of broccoli plants, in order to study the effect of adding different concentrations of zinc oxide nanoparticles to the sulforaphane content of broccoli by using the soilless cultivation technique. The experiment was carried out using a completely randomized design (CRD) and included a study of 4 treatments, with nine repetitions for each treatment. The averages were compared at the probability level of 0.05, the results showed that the treated plants ZnO75 mg.l-1 significantly by recording the highest mean of 140.μg/g fresh weight, While the average of this trait decreased in plants treated with Cooper's full salt solution and ZnO150 mg.l-1, which recorded the lowest value for this trait, which were 39.25 and 41.26 μg/gm fresh weight, respectively. Compared with the control treatment Cooper's solution without zinc recorded an average of 59.59 μg/gm of fresh weight.

Exogenous Selenium Treatment Promotes Glucosinolate and Glucoraphanin Accumulation in Broccoli by Activating Their Biosynthesis and Transport Pathways

Supplementation using selenium (Se) on plants is an effective and widely used approach. It can not only be converted to more Se rich compounds but promote the accumulation of glucosinolates (GSLs) with anti-carcinogenic properties. However, the molecular mechanism of Se in regulating GSLs synthesis remains unclear. In the present study, we analyzed the effects of Se treatment (50 μM sodium selenite) on GSLs, glucoraphanin (4MSOB), and sulforaphane compounds in broccoli tissues. The transcript levels of genes involved in sulfur absorption and transport, GSLs biosynthesis, translocation, and degradation pathways were also evaluated. The study showed that Se treatment remarkably promoted the accumulation of total sulfur and total Se contents and increased Trp-derived GSLs levels in roots by 2 times. The 4MSOB concentration and sulforaphane content in fresh leaves was increased by 67% and 30% after Se treatment, respectively. For genes expressions, some genes involved in sulfate uptake and transporters, GSLs biosynthesis, and transporters were induced strongly upon Se exposure. Results revealed that exogenous Se treatment promotes the overaccumulation of GSLs and 4MSOB content in broccoli by activating the transcript levels of genes involved in sulfur absorption, GSLs biosynthesis, and translocation pathways.

Mitigation of arsenic in broccoli through consumptive use of ground water and pond water as sources for irrigation

ABSTRACT Arsenic (As) contamination in ground water is raising concerns due to indiscriminate irrigation for a large variety of crops. Therefore, it is a challenge to reduce As uptake in relation to safe human consumption either by reducing water supply or by improving water quality without major yield losses. The experiment was laid out in Randomized Block Design (RBD) replicated four times with five water management treatments viz. T1 = 100% shallow tube well (STW), T2 = 25% STW + 75% pond water (PW), T3 = 75% STW + 25% PW, T4 = 50% STW + 50% PW andT5 = 100% PW with broccoli (cv. Green Magic) as a test crop in an As-affected village of Ghetugachi, West Bengal, India. Plant and soil samples were collected during harvesting. The calculated hazard quotient (HQ) suggests that despite having higher yield, As content in broccoli under T1 is unfit for human consumption. T2 having a low HQ (0.564) and moderate crop water productivity (CWP) and irrigation water productivity (IWP) values (5.46 and 8.07, respectively) is marked as safest. T4 with moderately high HQ (0.776) and fairly high CWP and IWP (5.62 and 8.31, respectively) can be considered for areas having relatively less contamination.

Effect of pulsed electric field‐assisted extraction on recovery of sulforaphane from broccoli florets

AbstractSulforaphane (SFN) is an isothiocyanate occurring in broccoli, with exceptional health‐beneficial properties, such as anticancer, anti‐inflammatory, and anti‐hypertensive effects. Processes to maximize SFN content in broccoli developed until now are expensive and SFN bioavailability in the vegetable is not optimal. To increase SFN extraction yield from broccoli florets, it was proposed to complement traditional solvent extraction with pulsed electric field (PEF) as tissue disruption method enabling the reduction of mass transfer resistance in vegetable matrices. Tissue disruption methods enhance the performance of this process because it reduces mass transfer resistance. PEF is an innovative technology recently introduced in the food industry. We studied the effect of electric field strength (10 and 15 kV/cm) and time of exposure to the PEF treatment (30, 90, and 150 s) on the recovery of SFN from broccoli florets, using a statistical factorial design. Electric field strength and exposure time significantly affected SFN recovery in a positive way. PEFs increase SFN recovery by more than 50% compared to traditional extraction. This result was achieved at 150 s exposure to PEF and 10 kV/cm.Practical ApplicationsThe use of pulsed electric fields significantly improved sulforaphane recovery from broccoli in comparison with traditional extraction methods. Even though in this work the raw material was commercial broccoli heads, it is most likely that the results obtained here can be replicated using low‐value raw material, such as broccoli heads that do not meet commercial standards or crop discards. Accordingly, PEF technology constitutes an option for valorization of Brassicaceae agroindustry discards.

The Application of Fe-EDTA and Sodium Silicate Affects the Polyphenols Content in Broccoli and Radish Sprouts.

The effects of elicitors on broccoli (Brassica oleracea L. var. Italica) and radish (Raphanus sativus L.) sprouts were evaluated. Seeds and then sprouts were soaked daily for 30 min over 6 days in water (control) or a mixture of FeEDTA and sodium silicate or sodium silicate alone. The contents of the flavonoids and phenolic acids (free, esters, and glycosides) were determined using HPLC-ESI-MS/MS. Phenolic compounds were released from the esters after acid hydrolysis and from the glycosides using alkaline hydrolysis. Quercetin, kaempferol, (‒)-epicatechin, naringenin, apigenin, and luteolin derivatives were found in broccoli and radish sprouts, while derivatives of iso-rhamnetin, orientin, and vitexin were not present at measurable levels. The flavonoid contents, especially derivatives of quercetin, were considerably higher in the broccoli sprouts than in the radish sprouts. The quantitatively major phenolic acid content in the sprouts of both species was found to be p-hydroxybenzoic acid. Its content in the radish sprouts was several times higher than in the broccoli sprouts. The total flavonoid content of broccoli sprouts was 507–734 µg/g DW, while that of the radish sprouts ranged from 155 µg/g DW to 211 µg/g DW. In contrast, total phenolic acids were higher in radish sprouts, ranging from 11,548 to 13,789 µg/g DW, while in broccoli sprouts, they ranged from 2652 to 4527 µg/g DW, respectively. These differences resulted radish sprouts having higher antioxidant activity compared to broccoli sprouts. The applied elicitors increased the content of the total phenolic acids and the antioxidant activity of radish and broccoli sprouts, while they decreased the level of the total flavonoids in broccoli sprouts.

Evaluating the Anti-Inflammatory and Antioxidant Effects of Broccoli Treated with High Hydrostatic Pressure in Cell Models.

Isothiocyanates (ITCs) are important functional components of cruciferous vegetables. The principal isothiocyanate molecule in broccoli is sulforaphane (SFN), followed by erucin (ERN). They are sensitive to changes in temperature, especially high temperature environments where they are prone to degradation. The present study investigates the effects of high hydrostatic pressure on isothiocyanate content, myrosinase activity, and other functional components of broccoli, and evaluates its anti-inflammatory and antioxidant effects. Broccoli samples were treated with different pressures and for varying treatment times; 15 min at 400 MPa generated the highest amounts of isothiocyanates. The content of flavonoids and vitamin C were not affected by the high-pressure processing strategy, whereas total phenolic content (TPC) exhibited an increasing tendency with increasing pressure, indicating that high-pressure processing effectively prevents the loss of the heat-sensitive components and enhances the nutritional content. The activity of myrosinase (MYR) increased after high-pressure processing, indicating that the increase in isothiocyanate content is related to the stimulation of myrosinase activity by high-pressure processing. In other key enzymes, the ascorbate peroxidase (APX) activity was unaffected by high pressure, whereas peroxidase (POD) and polyphenol oxidase (PPO) activity exhibited a 1.54-fold increase after high-pressure processing, indicating that high pressures can effectively destroy oxidases and maintain food quality. With regards to efficacy evaluation, NO production was inhibited and the expression levels of inducible nitric oxide synthase (iNOS) and Cyclooxygenase-2 (COX-2) were decreased in broccoli treated with high pressures, whereas the cell viability remained unaffected. The efficacy was more significant when the concentration of SFN was 60 mg·mL−1. In addition, at 10 mg·mL−1 SFN, the reduced/oxidized glutathione (GSH/GSSG) ratio in inflammatory macrophages increased from 5.99 to 9.41. In conclusion, high-pressure processing can increase the isothiocyanate content in broccoli, and has anti-inflammatory and anti-oxidant effects in cell-based evaluation strategies, providing a potential treatment strategy for raw materials or additives used in healthy foods.

Pre- and Post-harvest Factors Affecting Glucosinolate Content in Broccoli.

Owing to several presumed health-promoting biological activities, increased attention is being given to natural plant chemicals, especially those frequently entering the human diet. Glucosinolates (GLs) are the main bioactive compounds found in broccoli (Brassica oleracea L. var. italica Plenck). Their regular dietary assumption has been correlated with reduced risk of various types of neoplasms (lung, colon, pancreatic, breast, bladder, and prostate cancers), some degenerative diseases, such as Alzheimer's, and decreased incidence of cardiovascular pathologies. GL's synthesis pathway and regulation mechanism have been elucidated mainly in Arabidopsis. However, nearly 56 putative genes have been identified as involved in the B. oleracea GL pathway. It is widely recognized that there are several pre-harvest (genotype, growing environment, cultural practices, ripening stage, etc.) and post-harvest (harvesting, post-harvest treatments, packaging, storage, etc.) factors that affect GL synthesis, profiles, and levels in broccoli. Understanding how these factors act and interact in driving GL accumulation in the edible parts is essential for developing new broccoli cultivars with improved health-promoting bioactivity. In this regard, any systematic and comprehensive review outlining the effects of pre- and post-harvest factors on the accumulation of GLs in broccoli is not yet available. Thus, the goal of this paper is to fill this gap by giving a synoptic overview of the most relevant and recent literature. The existence of substantial cultivar-to-cultivar variation in GL content in response to pre-harvest factors and post-harvest manipulations has been highlighted and discussed. The paper also stresses the need for adapting particular pre- and post-harvest procedures for each particular genotype in order to maintain nutritious, fresh-like quality throughout the broccoli value chain.

Examination of glucoraphanin content in broccoli seedlings over growth and the impact of hormones and sulfur-containing compounds

In this study, we found that the glucoraphanin (GR) content in broccoli seedlings decreased before first foliage leaf emergence. Methyl jasmonate (MeJA) treatment significantly increased the GR content in broccoli, with effects being consistent over the period of application. Unlike MeJA, abscisic acid (ABA) and salicylic acid (SA) led to slight GR accumulation within 24 h of the application. The feeding of a sulfur-containing compound, MgSO4, via the root of broccoli caused accumulation of GR within 24 h. Thus, both the germination time and the duration of sulfur fertilization and MeJA application are important to maximize GR content in broccoli.

Chlorophyll degradation and carotenoid biosynthetic pathways: Gene expression and pigment content in broccoli during yellowing

Broccoli undergoes yellowing in unfavorable conditions, thereby diminishing the sensory quality and commodity value. This study aimed to investigate systematically cellular and/or biomolecular changes involved in broccoli yellowing by analyzing changes in microstructural integrity, pigment content, and gene expression. On day-5 of storage at 20 °C, the buds turned yellow without blooming and showed structural damage; ultrastructural analysis revealed plastid transformation and abnormal chloroplast development. Genes regulating pigment content and chloroplast structure directly were identified. More specifically, BoCAO and BoNYC1 regulated chlorophyll turnover, affecting chlorophyll a and b contents. Changes in the β-cryptoxanthin content were influenced by the combined action of up- (BoHYD) and downstream (BoZEP) genes. BoZEP and BoVDE were activated after cold-temperature induction. High BoHO1 expression delayed yellowing at low temperature, inducing BoZEP expression. Color intensity correlated significantly with the chlorophyll b, β-cryptoxanthin, and β-carotene contents, which were associated with increased yellowing of plant tissues.

Morphological and biochemical responses of broccoli florets to supplemental ultraviolet-B illumination

The effect of different doses of supplemental ultraviolet-B (UV-B) illumination on yield, plant growth, biochemical changes and antioxidant activity of broccoli florets was evaluated. The broccoli plants were grown under three different supplemental UV-B illumination doses (2.2, 8.8 and 16.4 kJ m−2 d−1) in the glasshouse. Plant height decreased with increasing supplementary UV-B illumination dose. However, leaf thickness increased with increasing UV-B dose. Chlorophyll content in the leaves also increased during the growing period. The lowest chlorophyll content was found at 16.4 kJ m−2 d−1 UV-B dose. Total yield decreased with supplemental illumination, especially at 16.4 kJ m−2 d−1 illuminated dose. Total dry matter, total soluble solids, carotenoids, chlorophyll a and b content in broccoli florets decreased with increasing UV-B illumination dose. Conversley, ascorbic acid, sinigrin, total phenolic, and flavonoid content and antioxidant activity increased in UV-B illuminated florets. Surprisingly, glucotropaeolin content, one of the forms of glucosinolate in broccoli, was not affected significantly by UV-B illumination or enhanced by UV-B illumination doses.

Effect of Biostimulants on Several Physiological Characteristics and Chlorophyll Content in Broccoli under Drought Stress and Re-watering

Drought stress is one of the many factors that lead to decreased yield in both quality and quantity. One method to improve plant resistance to this stress is application of biostimulants. The most widely used biostimulants are protein hydrolysates, containing sea algae extract and humus compounds. In the present study, the influence of the amino acids as well as combination of amino acids with Ascophyllum nodosum filtrate on broccoli (Brassica oleracea var. italica) plants cvs. ‘Agassi’ and ‘Tiburon’ was investigated. The plants were watered with Ascophyllum nodosum filtrate three days before planting and sprayed three times with amino acids two, four and six weeks after planting. The present results show that biostimulants have a significant effect on both gas exchange and transpiration rate both prior to the application of stress, under drought stress and after re-watering. Biostimulant treatment led to an increase of drought tolerance in both studied cultivars but the final effect depended on cultivar. ‘Tiburon’ cultivar turned out to be more tolerant to drought stress than ‘Agassi’. The application of biostimulants resulted in an increase of photosynthetic rate, stomatal conductance, internal CO2 concentration and transpiration rate in ‘Agassi’ cultivar under drought stress. This effect was not observed in ‘Tiburon’. The chlorophyll content was higher under drought stress as compared to the value prior to stress in both cultivars.

Influence of Different Cooking Methods on the Concentration of Glucosinolates and Vitamin C in Broccoli

Broccoli belongs to the Brassicaceae family and the Brassica genus, also designated crucifers, which has been linked to reduced risk of certain diseases for their content of compounds like glucosinolates (GLS) and vitamin C. Isothiocyanates, nitriles, and thiocyanates are degradation products of glucosinolates, are substances that protect cells against oxidative stress, and present many other health benefits. Vitamin C also contains antioxidant properties that contribute to the beneficial effects that broccoli have for health. The present paper is an overview of the reduction of secondary plant products, such as GLS and vitamin C, by cooking. Nonetheless, these concentrations can be modified if the cell structure of the plant is disrupted, e.g., while cutting, chewing, or cooking. Myrosinase can come into contact with GLS and hydrolyze it to isothiocyanate sulforaphane or sulforaphane nitrile, depending on the environmental conditions, which produces changes in the composition and concentration of GLS. Thus, cooking induces many chemical and physical modifications in food, among which GLS and vitamin C content in broccoli can change. Vitamin C and GLS are water-soluble, which makes them more susceptible to loss during the cooking process. Despite some controversy, most reviewed studies show that conventional cooking methods (boiling, steaming, and frying) and nonconventional ones (microwaving) significantly lead to the degradation of vitamin C and GLS. Nonetheless, steaming is the conventional method that obtains the best result to better preserve these two compounds.

Direct determination of total isothiocyanate content in broccoli using attenuated total reflectance infrared Fourier transform spectroscopy

The determination of total isothiocyanate content in broccoli is described using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and partial least-squares (PLS) algorithm. The spectral region of 2150–2020cm−1 was used for the total isothiocyanate quantification. The correlation coefficient was 0.99992, the root-mean-square error of calibration (RMSEC) was 1.74 and the root-mean-square error of prediction (RMSEP) was 2.17. The results were compared with those obtained from an established UV–Vis spectrophotometric method. The two methods were equivalent in reproducibility and accuracy (F-test, t-test). The proposed ATR FT-IR method is simpler and more rapid than the existing methods and constitutes a useful alternative for the determination of total isothiocyanates in broccoli.

Optimization of an incubation step to maximize sulforaphane content in pre-processed broccoli.

Sulforaphane is a powerful anticancer compound, found naturally in food, which comes from the hydrolysis of glucoraphanin, the main glucosinolate of broccoli. The aim of this work was to maximize sulforaphane content in broccoli by designing an incubation step after subjecting broccoli pieces to an optimized blanching step. Incubation was optimized through a Box-Behnken design using ascorbic acid concentration, incubation temperature and incubation time as factors. The optimal incubation conditions were 38°C for 3h and 0.22mg ascorbic acid per g fresh broccoli. The maximum sulforaphane concentration predicted by the model was 8.0µmolg-1, which was confirmed experimentally yielding a value of 8.1±0.3µmolg-1. This represents a 585% increase with respect to fresh broccoli and a 119% increase in relation to blanched broccoli, equivalent to a conversion of 94% of glucoraphanin. The process proposed here allows maximizing sulforaphane content, thus avoiding artificial chemical synthesis. The compound could probably be isolated from broccoli, and may find application as nutraceutical or functional ingredient.

The effect of the germination temperature on the phytochemical content of broccoli and rocket sprouts

This study investigates the effect of different germination temperatures (10, 20 and 30 °C) on the phytochemical content as well as reducing and antioxidant capacity of broccoli and rocket sprouts. In both seeds and sprouts, the total glucosinolates and ascorbic acid contents did not differ between vegetables, while broccoli exhibited exceptionally higher polyphenols and greater reducing and antioxidant capacity compared to rocket. In both species, an increase in germination temperature positively affected the glucosinolate content. Ascorbic acid increased during germination without a difference among the three tested temperatures. The phenol content in broccoli sprouts increased when they were grown at 30 °C, but the amount decreased at the highest temperatures in rocket. The reducing and antioxidant capacities increased with germination, and higher indexes were detected at 10 °C, particularly in rocket. Different germination temperatures differentiate the health-promoting phytochemical content and antioxidant properties in broccoli and rocket sprouts.

Alterations in Chlorophyll a Fluorescence and Pigments Concentration in the Leaves of Cauliflower and Broccoli Transplants Subjected to Chilling

Chlorophyll a fluorescence parameters and photosynthetic pigments content in leaves of broccoli (Brassica oleracea L. var.italica) cv. ‘Monaco’ F1 and cauliflower (Brassica oleracea L. var. botrytis) cv. ‘Bruce’ F1 transplants were analyzed to investigatethe effects of chilling temperatures (6 and 10 °C) and the exposure length (1 or 2 weeks) on the photosynthetic apparatuscondition in 3-year experiment. Data were compared to control plants exposed to 14 °C for 1 and 2 weeks. The lowest valuesof maximum quantum efficiency of photosystem II (Fv/Fm) and the performance index (PI) were observed in cauliflowerchilled at 6 °C for 2 weeks. This was not accompanied by any substantial reduction in chlorophylls concentration, however,significant correlations between Fv/Fm or PI and chlorophylls content in cauliflower leaves were found. There was no negativeeffects of chilling on photosynthetic activity and chlorophyll content in broccoli leaves, the amount of carotenoids significantlyincreased in the broccoli chilled for 2 weeks in 6 °C. The chlorophyll a fluorescence indices and accelerated carotenoidssynthesis showed that broccoli had less vulnerable photosynthetic apparatus to stress-induced temperatures and more efficientprotection mechanisms in comparison to cauliflower transplants.

Alterations in Chlorophyll a Fluorescence and Pigments Concentration in the Leaves of Cauliflower and Broccoli Transplants Subjected to Chilling

Chlorophyll a fluorescence parameters and photosynthetic pigments content in leaves of broccoli (Brassica oleracea L. var. italica) cv. ‘Monaco’ F1 and cauliflower (Brassica oleracea L. var. botrytis) cv. ‘Bruce’ F1 transplants were analyzed to investigate the effects of chilling temperatures (6 and 10 °C) and the exposure length (1 or 2 weeks) on the photosynthetic apparatus condition in the 3-year experiment. Data were compared to control plants exposed to 14 °C for 1 and 2 weeks. The lowest values of maximum quantum efficiency of photosystem II (Fv/Fm) and the performance index (PI) were observed in cauliflower chilled at 6 °C for 2 weeks. This was not accompanied by any substantial reduction in chlorophylls concentration, however, significant correlations between Fv/Fm or PI and chlorophylls content in cauliflower leaves were found. There were no negative effects of chilling on photosynthetic activity and chlorophyll content in broccoli leaves, the amount of carotenoids significantly increased in the broccoli chilled for 2 weeks at 6 °C. The chlorophyll a fluorescence indices and accelerated carotenoids synthesis showed that broccoli had less vulnerable photosynthetic apparatus to stress-induced temperatures and more efficient protection mechanisms in comparison to cauliflower transplants.