The Effect of 1-MCP on the Expression of Carotenoid, Chlorophyll Degradation, and Ethylene Response Factors in ‘Qihong’ Kiwifruit

The development of yellow color is an important aspect of fruit quality in yellow fleshed kiwifruit during fruit ripening, and it has a large influence on consumer preference. The yellow color is determined by carotenoid accumulation and chlorophyll degradation and is likely affected by ethylene production. This study investigates the expression of carotenoid, chlorophyll degradation, and ethylene response factors in ‘Qihong’ fruit, which had reached the near ripening stage (firmness ≈ 20 N) and were either left untreated (controls) or treated with 0.5 μL L−1 of 1-MCP for 12 h. Both the accumulation of β-carotene (not lutein) and degradation of chlorophyll a and b increased in response to the 1-MCP treatment, resulting in more yellow colored flesh in the 1-MCP treated fruit with higher carotenoid and lower chlorophyll contents. 1-MCP up-regulated AcLCY-β, AcSGR1, and AcPAO2, but reduced the expression of AcCCD1. These four genes were correlated with the concentrations of β-carotene and the chlorophylls. The expression of three ethylene response factors, including Acc29730, Acc25620, and Acc23763 were delayed and down-regulated in 1-MCP treated fruit, showing the highest correlation with the expression of AcLCY-β, AcSGR1, AcPAO2, and AcCCD1. Dual-Luciferase assays showed that 1-MCP treatment not only eliminated the inhibition of Acc23763 on the promoters of both AcPAO2 and AcLCY-β, but also reduced the activation of Acc29730 and Acc25620 on the AcCCD1 promoter. Our findings indicate that Acc29730, Acc25620, and Acc23763 may play an important role in the response to 1-MCP treatment during the fruit eating ripe stage, which likely altered the promoter activities of carotenoid and chlorophyll-related genes (AcPAO2, AcLCY-β and AcCCD1) to regulate their transcripts, resulting in more yellow color in the fruit flesh of ‘Qihong’.

Novel QTL For Lodging Resistance, PRL4, Improves Physical Properties With High Non-Structural Carbohydrate Accumulation of Basal Culms in Rice (Oryza Sativa L.)

Resistance to lodging, an important problem in rice production, has three types: low plant height, strong culm, and high strength of the lower part of the plant. The determinants of strength of the lower part remains unclear, compared with plant height and culm strength. This study identified a new genetic factor involved in the strength of the lower part, as assessed by pushing resistance, using chromosomal segment substitution lines (CSSLs) to clarify the determinants of strength of the lower part by functional analysis of the CSSL and the near isogenic line (NIL) harboring the identified quantitative trait locus (QTL). QTL analysis identified the QTL for increasing pushing resistance on chromosome 4, PRL4, which was not related to days to heading. The CSSL with PRL4 showed increased pushing resistance and physical strength of the basal culm, but decreased filled grain ratio and grain weight. The NIL with PRL4, developed by backcrossing this CSSL, improved pushing resistance and the strain of culm until breaking under compression, and did not decrease yield traits. These lines with PRL4 increased the accumulation of non-structural carbohydrate (NSC) in the basal culm at the fully ripe stage. Thus, the genetic control of NSC accumulation in culms by PRL4 may improve the strength of the lower part by enhancing culm toughness with strength and ductility.

Effect of post-harvest temperature of tomato ‘Rinka 409’ on quality and autofluorescence during overripening

Japanese tomato cultivar ‘Rinka 409’ is suitable for harvesting at a fully ripe stage since it remains firm at the stage, resulting in longer shelf life. However, it is difficult to estimate the quality change because its color does not change after the fully ripe stage. For ‘Momotaro,’ we previously proposed a fluorescence-based indicator of overripening; however, its suitability for another cultivar, ‘Rinka 409’, and its relationship with temperature and quality were unclear. Therefore, in this study, we investigated the appropriateness of this fluorescence-based index for the above purposes. In 2021, 45 tomato seedlings planted in 2020 were harvested at the fully ripe stage and used for experiments. Weight loss and firmness were evaluated to determine the quality of the tomatoes. The post-harvest temperatures were set as 10, 17, and 25 °C. The results showed that the rate of weight loss increased linearly, whereas the firmness decreased exponentially. For non-destructive estimation of these properties, the excitation-emission matrix (EEM) was measured in the range of 250–460 nm and 280–750 nm for the excitation and emission, respectively. ‘Rinka 409’ showed a strong fluorescence emission at 400 nm/620 nm of the excitation/emission, respectively, regardless of days and temperature. The fluorescence intensity, as well as the firmness, decreased exponentially. Thus, a linear relationship was observed between them. The firmness of ‘Rinka 409’ can be estimated using a simpler linear regression model using this method than previous researches.

Analysis of toxic elements in leaves and fruits of loquat by inductively coupled plasma-mass spectrometry (ICP-MS)

This study aimed at analyzing the content of 10 toxic elements (Be, Al, Ti, As, Cd, Sn, Sb, Hg, Pb and Ag) in different tissues (leaf blade, seed, fruit peel and pulp) of loquat fruits, at different maturity stages (immature green, mature green and full ripe) from Fujian (Yun Xiao/Zhangzhou) in China, using inductively coupled plasma-mass spectrometry (ICP-MS), with microwave digestion. Results revealed that the concentrations of Be, Al and Hg in all observed tissues were significantly reduced with the change in maturity of fruits from immature green to full ripe. Whereas the toxicity of Ti, As, Cd, Sb and Pb were observed to be shifted from seed and pulp to peel and leaves. Tin concentration was increased in all observed tissues except seeds, while silver concentration was only increased in fruit peel of loquat. In sum up, toxic elements concentration detected in the fruit pulp of loquat, at full ripe stage, was found safe for human consumption.

Aromatic Profile of Hydroponically and Conventionally Grown Tomatoes

Hydroponics is a more environmentally friendly and economical way of growing crops that allows crops to be grown all year round, regardless of soil and climate conditions. Hydroponic cultivation of various fruits, vegetables, flowers, etc., is well known and used today. Tomatoes also play an important role in hydroponic cultivation. Tomatoes grown in this way should have a more pronounced aroma and flavor, and the fact that they are harvested at the ripe stage should also be reflected in the fresh red color and appropriate organoleptic characteristics of the fruit. This study was concerned with the sensory analysis of hydroponically grown tomatoes (Solanum lycopersicum) compared with conventionally grown tomatoes of the same species. Samples were evaluated by instrumental sensory analysis using an electronic nose as well as a sensory panel. In this study, the difference between hydroponically and conventionally grown tomatoes was demonstrated. These differences were also captured by the consumers (sensory panel). When analyzing the odor profile of the samples, we found that hydroponic tomatoes are characterized by the presence of chemical organic compounds, namely: 2-methylpropanol, 2,3-pentanedione, and (Z)-3-hexen-1-ol or 1-hexanol, which cause the fruity aroma of the fruit. These substances are very likely to characterize the differences between the tested samples. The electronic nose has shown to be a potentially suitable tool for detecting differences and identifying typical product markers, which may suggest its further use in food authentication detection. It is also interesting to find almost no correlation between the two methods studied.

Novel QTL For Lodging Resistance, PRL4, Improves Physical Properties With High Non-Structural Carbohydrate Accumulation of Basal Culms in Rice (Oryza Sativa L.)

Resistance to lodging, an important problem in rice production, has three types: low plant height, strong culm, and high strength of the lower part of the plant. The determinants of strength of the lower part remains unclear, compared with plant height and culm strength. This study identified a new genetic factor involved in the strength of the lower part, as assessed by pushing resistance, using chromosomal segment substitution lines (CSSLs) to clarify the determinants of strength of the lower part by functional analysis of the CSSL and the near isogenic line (NIL) harboring the identified quantitative trait locus (QTL). QTL analysis identified the QTL for increasing pushing resistance on chromosome 4, PRL4, which was not related to days to heading. The CSSL with PRL4 showed increased pushing resistance and physical strength of the basal culm, but decreased filled grain ratio and grain weight. The NIL with PRL4, developed by backcrossing this CSSL, improved pushing resistance and the strain of culm until breaking under compression, and did not decrease yield traits. These lines with PRL4 increased the accumulation of non-structural carbohydrate (NSC) in the basal culm at the fully ripe stage. Thus, the genetic control of NSC accumulation in culms by PRL4 may improve the strength of the lower part by enhancing culm toughness with strength and ductility.

Evaluation of the Tolerance Ability of Wheat Genotypes to Drought Stress: Dissection through Culm-Reserves Contribution and Grain Filling Physiology

Drought stress is one of the limiting factors for grain filling and yield in wheat. The grain filling and determinants of individual grain weight depend on current assimilation and extent of remobilization of culm reserves to grains. A pot experiment was conducted with eight wheat cultivars at the Pot House to study the grain filling and the contributions of reserves in culm, including the sheath to grain yield under drought stress. Drought stress was enforced by restricting irrigation during the grain-filling period. The plants (tillers) were harvested at anthesis, milk-ripe, and maturity. The changes in dry weights of leaves, culm with sheath, spikes, and grains; and the contribution of culm reserves to grain yield were determined. Results revealed that drought stress considerably decreased the grain filling duration by 15–24% and grain yield by 11–34%. Further, drought-induced early leaf senescence and reduced total dry matter production indicate the minimum contribution of current assimilation to grain yield. The stress reduced the contribution of culm reserves, the water-soluble carbohydrates (WSCs), to the grains. The accumulation of culm WSCs reached peak at milk ripe stage in control, varied from 28.6 to 84 mg culm−1 and that significantly reduced in the range from 14.9 to 40.6 mg culm−1 in stressed plants. The residual culm WSCs in control and stressed plants varied from 1.23 to 8.12 and 1.00 to 3.40 mg g−1 culm dry mass, respectively. BARI Gom 24 exhibited a higher contribution of culm WSCs to grain yield under drought, while the lowest contribution was found in Kanchan. Considering culm reserves WSCs and their remobilization along with other studied traits, BARI Gom 24 showed greater drought tolerance and revealed potential to grow under water deficit conditions in comparison to other cultivars.

Evaluation of Cell Wall Modification in Two Strawberry Cultivars with Contrasted Softness

During the ripening process of fruit, the solubilization and depolymerization of cell wall components takes place, which results in the loss of firmness or the softening of fruit. Recently, we reported that two different strawberry cultivars (“Cristal” and “Portola”) exhibit differences in their fruit softening values, with “Cristal” being the firmest and “Portola” being the softest. In the present work, we performed a comparative study of the changes in the physicochemical properties of the cell wall-associated polysaccharide contents of these two strawberry fruit cultivars via thermogravimetric analysis (TGA), combined with the first derivative of the thermogram (DTG) curves and morphological studies using scanning electron microscopy (SEM). The “Cristal” sample showed higher thermal stability than the “Portola” sample. Additionally, differences were observed between the “Cristal” and “Portola” samples at different stages, principally in Region II (temperatures between 200 °C and 350 °C), with a higher thermal stability evident in the green stage of the two cultivars. Notably, a higher thermal stability was observed in the green stage of the “Portola” sample. The highest percentage of cumulative depolymerization (PCD) was observed in the ripe stage of the “Portola” sample. The DTG curve showed four maximum peaks of degradation, which occurred between 170 °C and 350 °C. Finally, the existence of a relationship between fruit firmness and thermal stability was demonstrated for the two cultivars. This relationship was based on the morphological studies conducted using SEM, which provided new evidence through which to understand the changes within the cell wall polymers of these two strawberry cultivars during the ripening process.

Genotypic variation of wheat (Triticum aestivum L.) in grain filling and contribution of culm reserves to yield

To study the genotypic variation in the rate of grain filling and contribution of culm reserves to yield in wheat, an experiment was conducted consisting 12 popular cultivars of Bangladesh, viz., BARI Gom21 (Shatabdi), BARI Gom22 (Shufi), BARI Gom23 (Bijoy), BARI Gom24 (Prodip), BARI Gom25, BARI Gom26, Akbar (BAW 43), BARI Gom18 (Protiva), BARI Gom19 (Sourav), BARI Gom20 (Gourab), Agrani (BAW38), and Kanchan (BAW28). Tillers were sampled from anthesis to maturity to determine the changes in dry weights of different parts to examine the contribution of culm reserves to grain yield. The results in the experiment revealed that the grain yield varied from 2.61 to 5.35 ton/ha with the mean of 4.18 ton/ha. Among the cultivars BARI Gom24, BARI Gom26, BARI Gom19, and BARI Gom23 appeared as high yielders while Kanchan, Agrani, BARI Gom20, BARI Gom22 as the low yielders. Generally, high yielding cultivars showed higher total dry mass accumulation compared to low yielding ones. Moreover, high yielding cultivars also showed higher water soluble carbohydrates (WSCs) contents in culm at milk ripe stage than the low yielders. In general, contribution of culm WSCs to grain yield was more in high yielders than low yielders and it ranged from 2 to 29% of total grain weight. So, higher contribution of culm reserves resulted in higher grain yield of wheat.