Postharvest Biology and Technology of Ornamentals

1. Postharvest Biology and Technology of Ornamentals Putting science into practice Michael Reid, University of California, Davis Cai-Zhong Jiang, USDA-ARS, Davis

2. Ornamental Industry • Floriculture crops : Cut flowers, cut cultivated greens, foliage plants, potted flowering plants, annual bedding/garden plants, propagativefloriculture material • Nursery crops : Evergreens_broadleaf, coniferous, Trees_shade, flowering, Christmas, fruit and nut plants, transplants, shrubs and other ornamentals and propagation material

3. The California nursery and floriculture industry

4. Value of California’s agriculture Data from the California Department of Food and Agriculture.

5. Contrast with cookies

6. What’s the problem? • Low per capita consumption of cut flowers • Holidays • Weddings • Funerals • Very lowpersonal use

7. Purchases of Cut flowers (retail) per capita in 2002 (in NTD) • Switzerland 4000 • Netherlands 2400 • Belgium 1760 • Germany 1600 • U.K. 1600 • Italy 1320 • France 1320 • Spain 760 • Portugal 640 • Poland 280 • U.S. 200 • Russia 120 Source, Flower Council of Holland

8. The postharvest problems • Flowers are shipped long distances and stored for long times • >25% product losses in marketing chain • Flowers and potted plants don’t last long enough • International market, strong competition • Lower consumer satisfaction. Customers don’t return

9. Species and cultivar Temperature Damage and disease Watersupply Ethylene and other PGRs Food supply Growth Factors affecting the postharvest life of ornamentals

10. Genetic difference in vase life among rose genotypes

11. Temperature - why is it important? • Rate of deterioration a rate of respiration • Faster respiration, shorter life • Respiration increases exponentially with T

12. 0 2.5 5 7.5 10 12.5 Roses held 5 days at different temperaturesthen 8 days in vase life room at 20⁰C

13. Temperature, respiration rate & vase life in stock flowers

14. Postharvest Disease Postharvest disease (primarily caused by gray mold (Botrytis cinerea) is a common cause of poor quality and shortened vase life

15. Environment Host Pathogen Disease control strategies The disease life cycle Disease The disease triangle

16. Disease control – the pathogen • Reduce spore load • sanitation in field, greenhouse, shed • Prevent spore germination • reduce condensation, injury, temperature • Prevent fungal entry • care in handling

17. Disease control - the host • Maintain in good condition, grow healthy plants, enhance physiological resistance. • Molecular biology-introduce resistance genes • Select resistant cultivars-variance is commonly observed • Treat with fungicides

18. Fungicides • Rely on synthetic chemical fungicides • Effective • Applied by dipping, in fogs • Development of resistance • Safety & environmental concerns

19. Sodium hypochlorite (NaOCl) • A strong oxidizing agent with broad spectrum antimicrobial activity • Active ingredient in household bleach • Commonly used for reducing bacterial and fungal contamination on fruit and vegetable surfaces and in flower vase solutions

20. Using NaOCl to control Botrytis infection in cut rose

21. Optimal concentration of sodium hypochlorite for controlling botrytis on rose ‘Akito’ and ‘Gold Strike’ flowers

22. Water supply • Plants are mostly water (80-90%) • Loss of water causes • loss of quality • wilting • accelerated aging • (ethylene production)

23. Failure in water relations • Water uptake < transpiration • Xylem occlusion • Emboli • Hard water • Bacteria • Physiological plugs

24. Air emboli • Recut under water • Acidify the water • Use warm (or cold) water • Pressurize (20 cm H2O) • Use a brief detergent dip

25. Roses dehydrated 10% Recut Placed in different water depths Photograph taken after 4 hours Water depth 20 cm 10 cm5 cm

26. Bacterial contamination

27. The Problem Desiccation of potted plants Lack of proper watering At the retail level Control Training retail staff Treatments to close stomata Salt stress? ABA?

28. Chemical manipulation of ABA Level Well-watered NaClABA No water

29. Ethylene-dependent senescence • Carnation model system • Ethylene production prior to onset of natural senescence • Pollination accelerates ethylene production and senescence

30. Ed Sisler, NCSU Mimics ethylene, blocks the binding site Marketed for flowers as EthylBloc For fruits and vegetables as ‘SmartFresh’ 1-MCP - a new ethylene inhibitor Ethylene 1-MCP

31. Studies on environmental requirements • Experiments to determine the best treatment conditions • concentration • temperature • time of MCP exposure • effective duration

32. 1-MCP effects may be transient Day 2 Day 3 Day 1 Plants were treated with 1-MCP on day 0, then exposed to ethylene on days 1, 2 or 3

33. Other growth regulators • Gibberellins retard leaf yellowing • So do cytokinins • Including thidiazuron, at very low concentrations (5 µM)

34. Thidiazuron • A non-metabolized cytokinin analog • Mode of action not yet clear • Reduced metabolism of native cytokinins? • Triggers the cytokinin response mechanism?

35. At higher concentrations (500 µM)TDZ improves Iris opening and vase life Can stimulate opening of a second flower Plus TDZ No TDZ

36. Cyclamen after 2 months display Control TDZ

37. Food • Flowers need food to grow and develop • Sugar (sucrose, glucose, or fructose) provides all that is needed • Vase solutions should contain 1.5 – 3% sugar • Bacteria like sugar too – use a bactericide

38. Effect of sucrose pulse on Eustoma

39. Continued growth • Growth away from gravity • Growth towards light • Can cause quality loss • snapdragons, tulip, red-hot poker • Control • temperature • orientation • Chemicals • Naphthylphthalamic acid • Inhibits auxin transport

40. Effect of NPA pretreatment

41. USDA BARD_Israel American Floral Endowment Joseph H. Hill Memorial Foundation Mellano & Company Kitayama Brothers Goldsmith Seeds Rosen Tantau Acknowledgments