Increase In Soluble Sugar Content Research Articles

Effects of Steaming on Chemical Composition of Different Varieties of Purple-Fleshed Sweetpotato.

Purple-fleshed sweetpotatoes (PFSPs) are rich in anthocyanins and are one of the health foods of interest. In this study, the effects of steaming on the anthocyanin, starch, soluble sugar, volatile organic compounds (VOCs) and pasting properties of nine PFSPs from China were investigated. The anthocyanin content of raw PFSP ranged from 9 to 185 mg/100 g. The total starch content decreased and soluble sugar content increased in all purple potatoes after steaming. Among the nine PFSPs varieties, Guangshu20 showed the greatest decrease in starch content (30.61%) and the greatest increase in soluble sugar content (31.12%). The pasting properties affected the taste of the PFSPs, with Shuangpihuang having the lowest peak viscosity (720.33 cP) and Guangzishu12 having the highest peak viscosity (2501.67 cP). Correlation studies showed that the anthocyanin content and pasting properties were negatively correlated with most of the sensory indicators, whereas the soluble sugar content of steamed PFSPs was significantly positively correlated with sweetness. A total of 54 VOCs were identified in this study, and aldehydes and terpenoids were the major VOCs in PFSPs. This study provides a theoretical basis for the processing of different PFSP varieties.

Effects of Low-Temperature Stress on Cold Resistance Biochemical Characteristics of Dali and Siqiu Tea Seedlings

Cold stress causes considerable damage to tender tea seedlings. Previous studies have explored changes in the physiological and biochemical factors of tea in response to cold stress; however, the mechanisms of cold resistance in ancient tea tree plants are unclear. The aim of this study was to analyze the effects of 0 °C cold stress for 15 days and 24 °C ambient temperature recovery for 5 days on the physiological and biochemical characteristics of two representative old tea varieties: Dali tea and Siqiu tea. The results revealed significant changes in antioxidant, photosynthetic efficiency, and physiological and biochemical indicators in response to cold stress, with the two species exhibiting different patterns. Cold stress decreased chlorophyll and carotene content, Fv/Fm, Y(II), non-photochemical quenching coefficient, photochemical quenching, and superoxide dismutase (SOD) activity, and increased intercellular CO2 concentration and ascorbate peroxidase activity. Siqiu tea showed a higher increase in soluble sugar content and antioxidant enzyme activity and a lower accumulation of malondialdehyde and minimal fluorescence (F0) than Dali, indicating a greater tolerance to cold stress. Based on partial least-squares discriminant analysis, six key differential physiological indicators of cold resistance—water-soluble sugar, F0, peroxidase, catalase, SOD, and gas conductance—were identified. Our findings provide technical support for identifying ways to protect ancient tea trees from extreme weather conditions.

Creating a zero amylose barley with high soluble sugar content by genome editing.

Amylose biosynthesis is strictly associated with granule-bound starch synthase I (GBSSI) encoded by the Waxy gene. Mutagenesis of single bases in the Waxy gene, which induced by CRISPR/Cas9 genome editing, caused absence of intact GBSSI protein in grain of the edited line. The amylose and amylopectin contents of waxy mutants were zero and 31.73%, while those in the wild type were 33.50% and 39.00%, respectively. The absence of GBSSI protein led to increase in soluble sugar content to 37.30% compared with only 10.0% in the wild type. Sucrose and β-glucan, were 39.16% and 35.40% higher in waxy mutants than in the wild type, respectively. Transcriptome analysis identified differences between the wild type and waxy mutants that could partly explain the reduction in amylose and amylopectin contents and the increase in soluble sugar, sucrose and β-glucan contents. This waxy flour, which showed lower final viscosity and setback, and higher breakdown, could provide more option for food processing.

Prohexadione-calcium improves grape quality by regulating endogenous hormones, sugar and acid metabolism and related enzyme activities in grape berries.

Prohexadione-Calcium (Pro-Ca) plays key roles in improving fruit quality and yield by regulating various aspects of plant growth. However, the effects of how Pro-Ca regulates the regulation of sugar and acid balance and its impact on the production of volatile aroma substances during fruit growth and development are poorly understood. In this study, the Pro-Ca solutions developed at concentrations of 200, 400, 600 and 800 mg·L-1 were sprayed on the entire "Chardonnay" grape tree 22, 42, 62 and 82 days after initial flowering. The values of endogenous hormones, sugar and acid content, enzyme activities and flavor content were then measured in grapes 45, 65, 85 and 105 days (ripeness stage) after the initial flowering. The results showed that Pro-Ca had significant effects on fruits during development, including reducing ABA content, increasing ZT, GA3 and IAA levels, promoting fruit ripening and enhancing enzymes, which are involved in sugar and acid synthesis. Consequently, these effects led to an increase in sugar and acid content in the berries. Particularly during the ripening phase, the application of 600 mg L-1 Pro-Ca resulted in an increase in soluble sugar content of 11.28% and a significant increase in citric acid and malic acid content of 97.80% and 68.86%, respectively. Additionally, Pro-Ca treatment enhanced both the variety and quantity of aroma compounds present in the berries, with the 600 mg·L-1 Pro-Ca treatment showcasing the most favorable impact on volatile aroma compounds in 'Chardonnay' grapes. The levels of aldehydes, esters, alcohols, phenols, acids, ketones, and terpenes were significantly higher under the 600 mg·L-1 Pro-Ca treatment compared to those of control with 51.46 - 423.85% increase. In conclusion, Pro-Ca can regulate the content of endogenous hormones and the activities of enzymes related to sugar and acid metabolism in fruit, thereby increasing the content of soluble sugar and organic acid in fruit and the diversity and concentration of fruit aroma substances. Among them, foliar spraying 600mg · L-1 Pro-Ca has the best effect. In the future, we need to further understand the molecular mechanism of Pro-Ca in grape fruit to lay a solid foundation for quality improvement breeding.

Bacillus cereus enhances salt tolerance of cucumber seedlings by improving antioxidant metabolism and decreasing the ion toxicity

Salt stress poses a significant challenge to plants, exerting a detrimental impact on crop growth and yield. This study investigated the effects of the strain Bacillus cereus on plant growth, ion contents and antioxidant metabolism of cucumber seedlings under salt stress (150 mM NaCl). The results showed that B. cereus could colonize the roots system of cucumber, with peak colonization occurring on the 3rd day. Inoculation with B. cereus effectively alleviated the growth inhibition of cucumber seedlings induced by salt stress, resulting in improvements in plant height, stem diameter, fresh and dry weight. Furthermore, the Na+ content in cucumber seedlings subjected to salt stress was significantly reduced by 38.35 % in leaves and 38.19 % in roots upon B. cereus inoculation, while K+ content increased by 9.88 % and 168.34 % in leaves and roots, respectively. Additionally, B. cereus significantly enhanced antioxidant enzyme activity and antioxidant content, while reduced the levels of H2O2, MDA, and O2−. in cucumber seedlings under salt stress conditions. B. cereus-treated seedlings exhibited an increase in soluble sugar content by 35.27 % and 93.21 % in leaves, and 59.36 % and 128.78 % in roots, respectively. Moreover, B. cereus treatment significantly up-regulated the expression of salt tolerant gene in both cucumber leaves and roots. These results showed that B. cereus enhanced salt tolerance in cucumber seedlings by modulating the antioxidant defense system, maintaining ion homeostasis, and promoting the expression of stress-related genes, ultimately improving the growth of cucumber seedlings.

Effect of Red and Blue Light on the Growth and Antioxidant Activity of Alfalfa Sprouts

Alfalfa sprouts are popular as a gourmet vegetable that contains a variety of antioxidants with anti-cancer and anti-coronary heart disease properties. In this study, under a photosynthetic photon flux density (PPFD) of 30 mol·L−1 photoperiod of 12 h for 3 days, and a temperature of 25 ± 2 °C, we investigated the effects of different light qualities on the growth, nutritional quality and antioxidant activity of alfalfa sprouts by modulating LEDs with different red and blue ratios, and searched for suitable light-quality conditions for alfalfa sprout growth. The experimental results showed that the dark treatment favored the growth of alfalfa sprout hypocotyls and the increase of soluble sugar content; alfalfa fresh weight was the largest under the white and red light treatments; nitrate content was the lowest in the treatment with a red-to-blue ratio of 2:2 (2R2B); soluble proteins and total phenolic content were the highest in the treatment with red-to-blue ratio of 1:3 (1R3B); and the total antioxidant activity of sprouts was the highest in the blue light treatment.

Overwintering performance of bamboo leaves, and establishment of mathematical model for the distribution and introduction prediction of bamboos.

Bamboo has great economic values and is used extensively in many industries, and their natural distribution range was divided into 12 zones in China according to the temperature of their geographical distribution in previous works. Different bamboo species had significantly different abilities in low-temperature tolerance, which need to be considered carefully during ex-situ introduction. In this paper, we observed and evaluated the low-temperature damage of 19 bamboo species in winter, and measured the physiological changes of bamboo leaves. A total of 3060 leaf samples were obtained from 102 core collections in 34 bamboo species from the 5 regions of Chinese mainland for anatomical comparison, in order to screen out the key anatomical indicators related to their low-temperature tolerance and to establish a mathematical prediction model for bamboo introduction. The results showed that the low-temperature resistance of clustered bamboos was generally lower than that of the scattered bamboos. The decreased temperature led to the constant decrease of net photosynthetic rate and transpiration rate, but the increase of soluble sugar content in all bamboo species. There was no dormancy for all bamboo species in winter. The temperate bamboos showed lower photosynthesis as compared to tropical bamboos in winter. The leaf shape of bamboos was closely related to their distribution. A total of 13 leaf indicators were screened and more suitable to estimate the low-temperature tolerant abilities of bamboos and to predict their distribution. The MNLR (multiple nonlinear regression) mathematical model showed the highest fitting degree and the optimal prediction ability in the potential northernmost introduction range of bamboos. This study lay a foundation for bamboo introduction, and could also reduce the economic losses caused by the wrong introduction.

Acidified biochar improves lead tolerance and enhances morphological and biochemical attributes of mint in saline soil

Lead (Pb) toxicity is a significant environmental issue, especially in areas with a past of industrial activities and mining. The existence of Pb in the soil can have negative impacts on plant growth and development, and it can also pose a risk to human health through the food chain. Acidified carbon has shown promise as an effective management technology for mitigating Pb toxicity. This study provides important insights into the potential of acidified biochar as a low-cost and eco-friendly method for managing Pb-contaminated soils. The current study explores the effectiveness of acidified biochar (AB) in alleviating Pb stress in mint. The study involved two levels of Pb (0 = control and 200 mg/kg Pb) and four levels of AB as treatments (0, 0.45, 0.90, and 1.20%). Results indicate that 1.20% AB was the most effective treatment, significantly decreasing root and shoot Pb concentration while enhancing shoot and root fresh and dry weight, shoot and root length, and shoot and root N, P, and K concentration. Moreover, a significant decrease in MDA (0.45AB, 0.90AB, and 1.20AB caused a decline in MDA content by 14.3%, 27.8%, and 40.2%, respectively) and an increase in ascorbic acid (0.45AB, 0.90AB, and 1.20AB led to an increase in ascorbic acid content of 1.9%, 24.8%, and 28.4%, respectively) validated the effectiveness of 1.20% AB compared to the control. Adding 0.45AB, 0.90AB, and 1.20AB led to an increase in soluble sugar content of 15.6%, 27.5%, and 32.1%, respectively, compared to the treatment without AB. Further investigations at the field level are suggested to confirm the efficacy of 1.20% AB as the best treatment against Pb toxicity in saline soil conditions.

Integrated transcriptomic and metabolomics analysis reveals abscisic acid signal transduction and sugar metabolism pathways as defense responses to cold stress in Argyranthemum frutescens

Argyranthemum frutescens is an important ornamental plant, whose distribution and application is limited owing to its susceptibility to low temperatures. The molecular mechanisms underlying the response of A. frutescens to cold stress is unknown. We used physiology, transcriptome, and metabolome analyses to characterize responses of A. frutescens subjected to 12 h (Mu12) and 24 h (Mu24) of low-temperature treatment. The results showed enhanced s uperoxide dismutase (SOD) activity during low temperature treatment and an increase in soluble sugar content at 12 h followed by a sharp decrease. A large number of differentially expressed genes (DEGs) were detected in A. frutescens plants exposed to low temperature. The up-regulated DEGs related to flavonoid biosynthesis, circadian rhythm, phenylpropanoid biosynthesis, and phenylalanine metabolism were significantly enriched in 12 h and 24 h compared to control, while those related to photosynthesis-antenna protein and photosynthesis pathway were down-regulated. Increased expression of transcription factors (TFs), including MYB, AP2-EREBP, and NAC indicated their role in triggering cold-responsive genes in A. frutescens . In total, 205 differentially accumulated metabolites were enriched during the low-temperature treatment, including amino acids, carbohydrates, and organic acids. Levels of eleven common metabolites, including abscisic acid, were up-regulated following cold treatment. In addition, sucrose, trehalose, and maltose accumulated at 12 h, but their levels decreased at 24 h. Integrated metabolome and transcriptome analyses revealed that abscisic acid signal transduction showed a positive response under the low-temperature treatment and sugar metabolism as an early response to cold stress in A. frutescens . These results reveal the potential underlying mechanisms of the low-temperature response of A. frutescens, which would help improve the cold tolerance of A. frutescens and enable extended cultivation in temperate regions in the future. • Omics integration was performed to characterize cold responses of Argyranthemum frutescens. • SOD activity was enhanced during the low temperature treatment and soluble sugars content was increased at 12 h then decreased. • DEGs related to flavonoid biosynthesis, circadian rhythm, phenylpropanoid biosynthesis and phenylalanine metabolism were up-regulated, while DEGs involved in photosynthesis pathway were down-regulated. • ABA signal transduction and sugar metabolism pathways has positive response to cold stress in A.frutescens • TFs, including MYB, AP2-EREBP, and NAC have important role in cold tolerance of A. frutescens .

Comparative transcriptomic analysis provides insights into the molecular basis underlying pre-harvest sprouting in rice

BackgroundPre-harvest sprouting (PHS) is one of the most serious rice production constraints in areas where prolonged rainfall occurs during harvest. However, the molecular mechanisms of transcriptional regulation underlying PHS remain largely unknown.ResultsIn the current study, comparative transcriptome analyses were performed to characterize the similarities and differences between two rice varieties: PHS-sensitive Jiuxiangzhan (JXZ) and PHS-resistant Meixiangxinzhan (MXXZ). The physiological experimental results indicated that PHS causes a significant decrease in starch content and, in contrast, a significant increase in soluble sugar content and amylase activity. The extent of change in these physiological parameters in the sensitive variety JXZ was greater than that in the resistant variety MXXZ. A total of 9,602 DEGs were obtained from the transcriptome sequencing data, and 5,581 and 4,021 DEGs were identified in JXZ and MXXZ under high humidity conditions, respectively. The KEGG pathway enrichment analysis indicated that many DEGs under high humidity treatment were mainly linked to plant hormone signal transduction, carbon metabolism, starch and sucrose metabolism, and phenylpropanoid biosynthesis. Furthermore, the number of upregulated genes involved in these pathways was much higher in JXZ than in MXXZ, while the number of downregulated genes was higher in MXXZ than in JXZ. These results suggest that the physiological and biochemical processes of these pathways are more active in the PHS-sensitive JXZ than in the PHS-resistant MXXZ.ConclusionBased on these results, we inferred that PHS in rice results from altered phytohormone regulation, more active carbon metabolism and energy production, and enhanced phenylpropanoid biosynthesis. Our study provides a theoretical foundation for further elucidation of the complex regulatory mechanism of PHS in rice and the molecular breeding of PHS-resistant rice varieties.

Transcriptome Analyses Reveal the Role of Light in Releasing the Morphological Dormancy of Celery Seed by Integrating Plant Hormones, Sugar Metabolism and Endosperm Weakening.

Celery seed is known to be difficult to germinate due to its morphological dormancy. Light is the key signal to release morphological dormancy and promote seed germination. However, this mechanism has rarely been studied. We performed physiological, transcriptome analyses on celery seed exposed to light and dark to decipher the mechanism by which light promotes germination of celery seed. The results showed that light significantly enhanced the expression of gibberellin synthesis genes and abscisic acid degradation genes and inhibited the expression of abscisic acid synthesis genes and gibberellin degradation genes. Moreover, gibberellin synthesis inhibitor could completely inhibit the germination capacity of celery seed, indicating that gibberellin is indispensable in the process of celery seed germination. Compared with dark, light also increased the activity of α-amylase and β-amylase and the expression of related coding genes and promoted the degradation of starch and the increase of soluble sugar content, suggesting that light enhanced the sugar metabolism of celery seed. In addition, transcriptome analysis revealed that many genes related to endosperm weakening (cell wall remodeling enzymes, extension proteins) were up-regulated under light. It was also found that light promoted the accumulation of hydrogen peroxide in the radicle, which promoted the endosperm weakening process of celery seed. Our results thus indicated that light signal may promote the release of morphological dormancy through the simultaneous action of multiple factors.

Effects of tebuconazole application at different growth stages on rice grain quality of rice-based untargeted metabolomics.

Tebuconazole (TEB) is a pesticide widely used in crops and has a strong control effect on fungal pathogens. TEB abuse has caused many food safety problems. In this study, the TEB residue in rice and the effect of TEB on white rice quality were investigated. The results showed that under two spraying concentrations, the TEB residue in rice was 11.21-19.05μg/kg and 24.45-31.12μg/kg, and there was no food safety risk of pesticide residue. When applying TEB according to the instructions, no significant effect was found. However, when 3 times the recommended TEB concentration was used at the filling stage, the protein content of white rice decreased significantly from 106.52mg/g to 80.72mg/g. At the jointing，heading and filling stage, the amylose content of white rice decreased to 53.95mg/g, 48.77mg/g and 49.04mg/g from the blank control group. Plant metabolic analysis using LC-QTOF/MS revealed that the amino acid-related metabolic pathways in white rice were significantly affected by TEB. This is closely related to the decrease in protein accumulation in white rice and the stress response of rice plants. The increase in pantothenic acid content in white rice indicated that the glycolysis pathway of white rice plants was affected, and the consumption of starch and sucrose increased, leading to the inhibition of amylose accumulation in white rice. The increase in soluble sugar content and decrease in phosphocholine content in white rice suggested that rice plants were affected by TEB exposure, which produced similar effects under drought stress.

Transcriptome and phytochemical analyses reveal the roles of characteristic metabolites in the taste formation of white tea during the withering process

In the postharvest processing of tea leaves, withering is the first indispensable manufacturing process which produces the mellow, umami and sweet taste of white tea. In this study, we aimed to determine the dynamic changes of the main metabolites and clarify the key differentially expressed genes (DEGs) involved in forming the characteristic taste of white tea during withering. Phytochemical analyses revealed that the contents of total catechins and starch decreased continuously, whereas the contents of theaflavin, γ-aminobutyric acid (GABA), maltose, and soluble sugars increased significantly during withering (from 0–48 h). Meanwhile, the elevation of α-amylase (AMY), β-amylase (BAM), total amylase, and glutamate decarboxylase (GAD) activities may be correlated with the accumulation of GABA and maltose. By transcriptome sequencing, we detected 9 707, 15 921, 17 353, and 17 538 DEGs at 12, 24, 36, and 48 h of the withering process, respectively, compared with 0 h sample (fresh leaves). The transcript levels of most of the DEGs involved in catechin biosynthesis were significantly inhibited, whereas those involved in catechin oxidation were significantly up-regulated, which could be correlated to a decrease in catechin content and an increase in theaflavin content. The DEGs involved in GABA biosynthesis were considerably up-regulated, and the down-regulation of SPMS could reduce the competition for converting spermidine to GABA. The up-regulation of the AMY and BAM genes could trigger starch degradation, resulting in the increase of soluble sugar content. These results provide new insights into the importance of the withering process to the characteristic taste of white tea.

Comparative analysis of drought-responsive and -adaptive genes in Chinese wingnut (Pterocarya stenoptera C. DC)

BackgroundDrought is the main stress factor for the cultivation of Pterocarya stenoptera in urban areas, and this factor will cause its dehydration and affect its growth. Identifying drought-related genes will be useful for understanding the drought adaptation mechanism of P. stenoptera.ResultsWe used physiological indicator detection, comparative transcriptome sequencing, and reanalysis on the results of previous landscape genomics studies to investigate the drought adaptation mechanism in P. stenoptera. The changes in malondialdehyde content showed that P. stenoptera was remarkably affected by drought stress, and the increase in soluble sugar content suggested its important role in response to drought stress. Results of comparative transcriptome sequencing showed that P. stenoptera initiated a series of programs, such as increasing the gene expression of unsaturated fatty acids, tyrosine, and plant pathogen resistance, to deal with the transient drought stress. According to the annotated results in a previous study, P. stenoptera adapts to the long-term differential drought stress by regulating the thickness of cell walls and expressing upper or lower limits of the downstream genes in the hormone signaling pathway. Through the comparative analysis of drought-responsive and -adaptive genes in P. stenoptera, this study supports the hypothesis that the environment-responsive genes (ERGs) introduced by the transient environmental stresses will be substantially more than the environment-adaptive genes (EAGs) in response to long-term differential environmental stresses, and the EAGs are not necessarily ERGs.ConclusionsOur study identified drought-responsive and -adaptive genes in P. stenoptera and revealed that P. stenoptera increased the gene expression of unsaturated fatty acids, tyrosine, and plant pathogen resistance in response to transient drought stress. This study reveals the different adaptation mechanism of P. stenoptera under the transient and long-term differential drought stresses.

Low temperature acclimation and de-acclimation of the subtropical bromeliad Nidularium minutum: Implications of changes in the NO, sugar content and NR activity

In tropical biomes, abrupt cold events frequently occur in subtropical regions and can be associated with large daily thermal fluctuations. The bromeliad Nidularium minutum Mez is a cold tolerant species from the Atlantic Rainforest, which grows in the subtropical latitude, where temperatures range from 2 to 30 °C. We hypothesized that N. minutum plants would implement rapid metabolic adjustments to ensure survival during sudden cold events that occur in seasons other than winter. N. minutum plants were cultivated at 10 °C. Under this condition, there was an observed increase in soluble sugar content and nitric oxide (NO) emission, as well as a high nitrate reductase (NR) activity observed within the 72 h of cold exposure, when compared with plants maintained at 25 °C. These responses coincided with a decrease in antioxidant activity and an increase in lipid peroxidation (LPO). After 72 h of cold exposure, a subset of plants were de-acclimated at 25 °C. These plants displayed reduced soluble sugar concentrations, NO emissions, NR activity and LPO. Additionally, there was an increase in antioxidant activity, which indicated that the plants were recovering from cold stress. Furthermore, it was found that plants maintained at 10 °C for 168 h acclimated to the cold by reducing the NO content and maintaining the increased sugar concentrations, thus resulting in a less intense stress response. We conclude that rapid changes in NO content, sugar concentrations and antioxidant activity are metabolic adjustments that occur during the acclimation and de-acclimation processes of this bromeliad to low temperatures. During abrupt thermal changes in subtropical regions, such adjustments could enhance cold tolerance and increase the chances of survival for this plant.

Comparative growth and physiological responses of tetraploid and hexaploid species of wheat to flooding stress

Present study is aimed to comparatively investigate the response of two ploidy levels of wheat including a tetraploid (Triticum turgidum L.) and a hexaploid (Triticum aestivum L.) wheat to different durations of flooding stress. Wheat seedlings were exposed to flooding stress for 0, 3, 6 and 9 days. Results showed that all flooding treatments significantly decreased the shoot and root length, and chlorophyll content of both species of wheat. The decrease in chlorophyll content of tetraploid wheat was more than that of hexaploid one. In both species, ADH activity of root was significantly increased under flooding stress, where the increase was more in hexaploid wheat. Flooding stress did not significantly affect root and shoot water content, root porosity, and shoot protein content of any wheat species. Tetraploid and hexaploid wheat used different mechanisms for better tolerance of flooding condition, where tetraploid wheat increased the proline content but in hexaploid wheat, an increase in soluble sugar content was observed.

Physiological and proteomic analysis of salinity tolerance of the halotolerant cyanobacterium Anabaena sp.

The halotolerant cyanobacterium Anabaena sp was grown under NaCl concentration of 0, 170 and 515mM and physiological and proteomic analysis was performed. At 515mM NaCl the cyanobacterium showed reduced photosynthetic activities and significant increase in soluble sugar content, proline and SOD activity. On the other hand Anabaena sp grown at 170mM NaCl showed optimal growth, photosynthetic activities and comparatively low soluble sugar content, proline accumulation and SOD activity. The intracellular Na(+) content of the cells increased both at 170 and 515mM NaCl. In contrast, the K(+) content of the cyanobacterium Anabaena sp remained stable in response to growth at identical concentration of NaCl. While cells grown at 170mM NaCl showed highest intracellular K(+)/Na(+) ratio, salinity level of 515mM NaCl resulted in reduced ratio of K(+)/Na(+). Proteomic analysis revealed 50 salt-responsive proteins in the cyanobacterium Anabaena sp under salt treatment compared with control. Ten protein spots were subjected to MALDI-TOF-MS/MS analysis and the identified proteins are involved in photosynthesis, protein folding, cell organization and energy metabolism. Differential expression of proteins related to photosynthesis, energy metabolism was observed in Anabaena sp grown at 170mM NaCl. At 170mM NaCl increased expression of photosynthesis related proteins and effective osmotic adjustment through increased antioxidant enzymes and modulation of intracellular ions contributed to better salinity tolerance and optimal growth. On the contrary, increased intracellular Na(+) content coupled with down regulation of photosynthetic and energy related proteins resulted in reduced growth at 515mM NaCl. Therefore reduced growth at 515mM NaCl could be due to accumulation of Na(+) ions and requirement to maintain higher organic osmolytes and antioxidants which is energy intensive. The results thus show that the basis of salt tolerance is different when the halotolerant cyanobacterium Anabaena sp is grown under low and high salinity levels.

Relationships between carbohydrates and reproductive development in chardonnay grapevine: impact of defoliation and fruit removal treatments during four successive growing seasons

<p style="text-align: justify;"><strong>Aim</strong>: The present study was conducted in grapevines to evaluate the influence of source/sink disturbance on reserve restoration in the entire plant (trunk, roots) and the consequences on reproduction, yield, sugar yield, potential alcohol content and total acidity over four successive years of treatment.</p><p style="text-align: justify;"><strong>Methods and results</strong>: At véraison, either total defoliation or total fruit removal was performed on Chardonnay plants grown in vineyards. The impact was measured each year on reproductive parameters and after four years on both plant weight and carbohydrate content. Defoliation induced an alteration in carbohydrate distribution in the entire plant, as revealed by decrease of starch content and parallel increase of soluble sugar content. These modifications affected the number of inflorescences/clusters per plant the year after. By contrast, fruit removal resulted in a significant increase of carbohydrate reserves in the whole plant, although the efficiency of sexual reproduction was not improved the year after.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Results confirm the close correlation between carbohydrate reserves and the efficiency of sexual reproduction. Moreover, grapevine is able to adapt the number of both inflorescences and flowers according to the amount of available carbohydrate reserves in perennial organs.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The quality of the crop is affected by defoliation, as shown by the decrease in yield and sugar yield. However, the impact on potential alcohol content and total acidity was less pronounced.</p>

Effects of different K fertilizer and water level on growth and physiological characteristics of Isatis indigotica

The experiment included three potassium levels (K0 0 g x kg(-1), K1 0.33 g x kg(-1), K2 0.67 g x kg(-1)) and two water gradients (well watered and drought stress), then measured growth indicators, SOD, POD, CAT activities and concents of osmotic regulation substances. To explore the effects of K fertilizer and water on growth and physiological characteristics of Isatis indigotica, providing reference for improving drought resistance of I. indigotica. The result showed drought stress inhibited the growth and decreased the biomass of I. indigotica but K fertilizer can alleviate the drought stress. Compared with K0 treatment, K1, K2 treatment increased the biomass of overground part of by 89. 13% ,60. 87% under drought stress. The corresponding increase in soluble sugar content was 16.67%, 5.00%, and in proline content was 42.41%, 65.62%, respectively. SOD,POD and CAT activities was significantly improved in K1, K2 treatment in comparison with K0 treatment under drought stress, but soluble protein content significantly reduced. The conclusion is that appropriate amount of K fertilizer can increase the activities of antioxidase and the content of osmoregulation substance under drought stress, and improve drought resistance of I. indigotica.

REDUCING NITRATE CONTENT IN LETTUCE BY PRE-HARVEST CONTINUOUS LIGHT DELIVERED BY RED AND BLUE LIGHT-EMITTING DIODES

Effect of pre-harvest continuous light with different red/blue ratio on photon flux density (R/B ratio) on reducing nitrate accumulation was studied by growing lettuce (Lactuca sativa L.) under continuous illumination delivered by light-emitting diodes (LEDs). Results show that nitrate concentration decreased by 1648.0–2061.1 mg kg−1 in leaf blade and 962.9–2090.3 mg kg−1 in petiole, accompanied by a dramatic increase in soluble sugar content. Compared with monochromatic red light treatment, the decrease in nitrate concentration and increase in soluble sugar content in lettuce under mixed red and blue light were more pronounced. The lowest nitrate concentration was observed in the treatment with R/B ratio of 4. It's concluded that pre-harvest exposure to 48 h continuous LED light could effectively reduce nitrate accumulation in lettuce and this process is strongly affected by R/B ratio of light. This study may provide new perspective for pre-harvest quality management of vegetable, especially in commercial leaf vegetable production under artificial lighting.