Figures (9)  Tables (2)

    • Figure 1. 

      Internal structure of immature sponge gourd fruit (left) and visual appearance of immature sponge gourd fruit stored at (a) 25 °C and (b) 5 °C[3].

    • Figure 2. 

      Chilling injury symptoms generated on young leaves of holy basil (upper right) and sweet basil (below right) during 4 °C storage, compared to non-chilled leaves (left).

    • Figure 3. 

      Subcellular location of antioxidant enzymes in plant cells.

    • Figure 4. 

      Proposed mechanisms of membrane lipid components related to CI sensitivity and tolerance under low temperature.

    • Figure 5. 

      Long section fruit-cut of Queen pineapple (upper) (a) on the harvesting day and (b) fruit stored at 13 °C for 14 d generating internal browning. The flesh tissues of a fruitlet adjacent to the core (in the circle) of fruit cross-sectioned and photographed under a confocal microscope (below) (sourced from Dr. Panipa Youryon with permission).

    • Figure 6. 

      ROS induced by low temperature and the enzymatic scavenging systems (modified from Noichinda et al.[24]).

    • Figure 7. 

      Photomicrographs of internal chilling injuries (CI) symptoms in immature sponge gourd tissue after Evans blue dye staining, (a)−(f ) were 2, 4, 6, 8, 10, and 12 d during storage at 5 °C. Arrow pointed Evans blue dye staining area: CH = chlorenchyma, PA = parenchyma, and XY = xylem vessel. (Scale bar = 100 μm)[3].

    • Figure 8. 

      CI appearances of (a) okra pods and (b) SEM pictures of the peel stored at 4 °C for 12 d at normal surface at 100× and at (c) the collapsed surface at 200× (sourced from Dr. Surisa Phornvillay with permission).

    • Figure 9. 

      The proposed chilling injury (CI) sensitivity and tolerance in immature sponge gourd fruit during storage at low temperature conditions: induce [+] and inhibit [–].

    • Horticultural
      commodity      		Critical temperature
      ( °C)      		CI response
      (+)      		SymptomsRef.
      ExternalInternal
      Banana13−15+Skin-darkeningPoor ripening[6]
      Mango13−15+Senescent spotting, brown skinPoor ripening[7]
      Papaya13+ +Surface pittingWater-soaking[8]
      Pineapple
      - Queen11−13+ ++Pink bract of fruitletsInternal browning[9]
      - Smooth cayenne13+Non-responseInternal browning
      Ripe tomato14+Surface pittingExcessive softening, water soaking, aroma loss[10]
      Asparagus0−2+Dull, grey-green, limp tips[11,12]
      Bean7+Pitting and russeting[11]
      Eggplant7++Surface scald,Seed blackening[11]
      Gourd10−13++Surface pitting and browningSeed browning[3,11,12]
      Cucumber8−10++Surface pittingWater soaking[11,12]
      Zucchini0+Surface pitting[12]
      Summer squash5−10+Surface pitting and fungal rotBreakdown[13]
      Gac fruit10−13+Fruit shriveling, water soaking peelWater leathery like mesocarp and aril[14]
      Chili7+Surface pittingPlacenta and seed browning[15]
      Okra8−10+Surface pittingSeed browning[16,17]
      Chinese kale4−8+Water soaking peel[18]
      Sweet basil12++Leaf browning, necrosis, decay, and leaf abscission[19]
      Holy basil12++Browning spots and water soaking leaves[20]
      Lemon basil12++Leaf blackening[5]
      (+) degree of susceptibility to CI.

      Table 1. 

      Critical temperature, CI response and symptoms of some tropical horticultural commodities.

    • FormNameFormName
      O2·−Superoxide radical1O2Singlet oxygen
      OH·Hydroxy radicalH2O2Hydrogen peroxide
      RO·Alkoxyl radicalROO·Alkylperoxyl radical
      ROOHAlkylhydroperoxideClO−Hypochlorite ion
      Fe5+OPeriferryl ionFe4+OFerryl ion
      NO·Nitric oxide

      Table 2. 

      General ROS produced in plant cells under low temperature storage.