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Production temperature effects on anatomy, morphology, physiology and postharvest longevity of Leatherleaf fern (Rumohra adiantiformis (Forst.) Ching)

Stamps, Robert Huguenor

Ph.D., University of Florida, 1984, 142 pages.

1984

บทคัดย่อ

PRODUCTION TEMPERATURE EFFECTS ON ANATOMY, MORPHOLOGY, PHYSIOLOGY AND POSTHARVEST LONGEVITY OF LEATHERLEAF FERN (RUMOHRA ADIANTIFORMIS (FORST.) CHING).

Leatherleaf fern, Rumohra adiantiformis (Forst.) Ching, was grown under 2 temperature regimes in controlled environment chambers.  The chambers had the same photosynthetic photon flux density, but half the chambers had high (30(DEGREES)C day/25(DEGREES)C night) and the other half had low (20(DEGREES)/15(DEGREES)) temperature regimes.  These regimes approximate those found in Florida during the months when postharvest longevity of leatherleaf fern fronds are low and high, respectively.

 Fronds produced under the high temperature regime (HTR) grew faster initially and produced sori sooner than low temperature regime (LTR) ones.  Fronds from both treatments were hypostomatous, anomocytic, and stipe tracheids had scalariform pitting.

 Light saturated carbon exchange, quantum efficiences, and dark respiration were lower for HTR grown fronds than LTR fronds when measured at 30.5(DEGREES).  Light compensation points, water use efficiency, photosynthetic efficiency, and soluble sugar and starch content were similar for fronds from both treatments.  Abaxial diffusive conductance (g(,wv)) of HTR fronds was lower than for fronds grown under the LTR.  The lower g(,wv) may have been due to greater physiological age or to preconditioning of HTR fronds.

 Temperature treatments did not affect frond weights, surface areas, water content, stomatal density, cuticle thickness, or number of epidermal layers, but leaf density thickness, specific leaf weights, pinnule thickness and vascularization, endodermal wall thickening, and stipe vascular bundle numbers and cross-sectional areas were reduced for HTR fronds.  Relative conductivities of freshly harvested stipes were 39% lower for HTR fronds than LTR fronds.

 Postharvest water uptake of HTR fronds was 36 to 50% lower than LTR uptake.  In 3 experiments, vase life or HTR fronds was reduced 28 to 66% compared to LTR fronds.  HTR fronds lost weight more rapidly after harvest.  Vase life was positively correlated with stipe cross-sectional area and initial water uptake.  Stipe recutting 1 to 6 days postharvest increased g(,wv) and water uptake of both frond types.

 Plants were switched from one temperature regime to the other.  Former production temperature effects predominated for the first harvest of fronds produced under the latter temperature regime.  The second crop of fronds was mainly influenced by the latter production temperature regime.