Sensory and metabolic profiles of “Fuji” apples (<i>Malus domestica</i> Borkh.) grown without synthetic agrochemicals: the role of ethylene production

<p>Flavors of “Fuji” apple cultivated with or without synthetic agrochemicals were compared using quantitative descriptive analyses (QDA) and metabolite profiling for 3 seasons. Experimental plots included conventional crops (with agrochemicals) and organic crops (without agrochemicals) at our institute and organic and conventional farms. Additionally, mass market samples were analyzed. Organic apples were weak in sweetness and floral characteristics and had enhanced green and sour flavors. Most esters and sugars were present in lower concentrations in organic than in conventional apples. Close relation of principal component 1 of QDA and metabolite profiles, to ethylene production suggested that ethylene is considerably involved in flavor synthesis. Reduced ethylene associated with immaturity accounted for insufficient flavor synthesis and weak aroma and flavor attributes of organic apples. Furthermore, organic apples from the farm were more flavorsome than those from the institute in 2012, suggesting possible recovery of ethylene production after a long organic cultivation period.</p> <p>Organic “Fuji” apples, which were weak in sweet and floral characteristics and had lower levels of esters, were accounted for by smaller ethylene.</p

Transverse sections of a typical ring-shaped chalky kernel (A); and expanded SEM images taken at the three zones (B–D) shown in A.

<p>B, C, and D indicate the border between the inner translucent and chalky region (chalky cell in the left corner cell), the chalky region with loosely packed starch granules, and the translucent zone, respectively. The distance (<i>r</i>) from the endosperm center along the semi-minor axis in ring-shaped chalky kernels as a putative function of the duration of dry wind conditions (E). In E, the inner and outer borders of translucence and chalkiness correspond to the initiation of the dry wind treatment and the recovery point observed at 52 h in Fig. 2A, respectively; B, C, and D are indicated by arrows. ‘Epi’ indicates epidermis. In B–D, note that fissured fractures in each figure correspond to the cell wall. Bars in A and in B–D indicate 1 mm and 10 µm, respectively.</p

Isotopic ratio of ¹³C-labeled sodiated glucose, (<i>m/z</i> = 204 to <i>m/z</i> = 203) detected in the ethanol-insoluble fraction in kernels sampled at 24 h after the initiation of dry wind treatment.

<p>The plants were labeled with ¹³CO₂ at 12 days after heading (DAH) from the flag leaf to pre-fix ¹³C in the kernels prior to initiation of the dry wind treatment at 13 DAH.</p><p>Values indicate the mean ± SE of three biological replications of two pooled kernels.</p><p>Isotopic ratio of ¹³C-labeled sodiated glucose, (<i>m/z</i> = 204 to <i>m/z</i> = 203) detected in the ethanol-insoluble fraction in kernels sampled at 24 h after the initiation of dry wind treatment.</p

Time course of changes in ¹³C distribution in kernels located in the same position where an in situ turgor assay was conducted (A); in the panicle excluding the kernels (B); in the flag leaf (C); and in culms and leaf sheaths (determined as pooled organs with flag leaf sheath, uppermost internode, and other tissues) (D), corresponding to the sampled locations shown in the schematic potted plant to the right of the figure panels.

<p>‘M’ on <i>x</i>-axis indicates maturation. The plants were labeled with ¹³CO₂ for 20 min from the flag leaf at 13 DAH, just before the dry wind treatment was initiated, as indicated by the arrow. Open and closed circles indicate the control and dry wind treatments, respectively. Gray areas indicate the dry wind treatment. Each point is the mean ± SE of three samples from different plants. Significance at the 0.05, 0.001 and 0.0001 probability levels is indicated by *, **, and ***, respectively.</p

Expression profiling of starch degradation-related genes (A) and starch biosynthesis-related genes (B) in the growing kernels after 24 h of dry wind treatment.

<p>Inset in A is an expansion of the figure showing the expression of four α-amylase-encoding genes. Black and white bars indicate dry wind and control treatments, respectively. Data are the mean ± SE (<i>n</i> = 3) of four inferior kernels pooled at the position in the panicles where the in situ Ψ_p assay was conducted. Significance at the 0.05 and 0.01 probability levels is indicated by * and **, respectively.</p

Percentage of filled kernels, final kernel weight, and rice appearance of tertiary pedicels attached at the middle primary rachis branches, where an in situ turgor assay was conducted, in a panicle grown under 24, 48, or 72 h dry wind treatment in growth chambers.

a<p>PR = perfect rice; MWR = milky white rice (ring-shaped chalky kernels); OR = other rice appearance.</p><p>Values in each treatment are means ± SE of four biological replications of panicles.</p><p>Means within a column followed by different letters are significantly different (<i>P</i><0.05) (Tukey’s Honestly Significant Difference [HSD] test).</p><p>Percentage of filled kernels, final kernel weight, and rice appearance of tertiary pedicels attached at the middle primary rachis branches, where an in situ turgor assay was conducted, in a panicle grown under 24, 48, or 72 h dry wind treatment in growth chambers.</p

Time course of changes in kernel growth score (A) visually observed through hull; definition of kernel growth scores, 0 through 1.0 (B); and changes in leaf water potential (LWP) (C), photosynthesis rate (D), and kernel weight (E) under 24 h dry wind conditions, starting at 13 days after heading (DAH).

<p>Open and closed circles indicate control and dry wind treatments, respectively. Gray area indicates the 24-h dry wind treatment. For A, each point is the mean ± SD of at least 20 kernels from 4 different plants; for C–E, each point is the mean ± SE of 3–6 samples from different plants.</p

Changes in panicle water potential (PWP) (A), stem water potential (SWP) (B), endosperm cell turgor (C), and the weight-averaged calculated endosperm osmotic potential (D) in developing rice kernels under dry wind conditions.

<p>Open and closed circles indicate control and dry wind treatments, respectively. In D, the inset indicates kernel water potential measured with an isopiestic psychrometer as a function of panicle water potential measured with a pressure chamber in both the control and dry wind treatments, collected at 13 days after heading (DAH) (open squares) and 14 DAH (closed squares). The gray zone indicates the duration of dry wind treatment, corresponding to 13 DAH. In the inset in panel D, the slanted dotted line labeled ‘1∶1’ indicates an equipotential line. The solid line indicates the regression line at 13 DAH. For A and B, each point is the mean ± SE of 3–19 samples from different plants. For C, data are means ± SE of 4–22 cells measured in 2–8 inferior grains in the same location on a panicle.</p

The aza-sugars composition of administration samples.

<p>The aza-sugars composition of administration samples.</p

The recovery rate of ¹⁵N from DNJ in urine and feces until 48 hours after sample administration.

<p>The recovery rate of ¹⁵N from DNJ in urine and feces until 48 hours after sample administration. After 12 hours fasting, the rats were received ¹⁵N-labeled DNJ (10 mg). Urine and feces were collected and the amount of ¹⁵N from DNJ was analyzed. (a) The time course of recovery rate of ¹⁵N in urine. (b) Total recovery rate of ¹⁵N in urine and feces. Results are given as means ± SE.</p