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  • Author or Editor: F. Takeda x
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Abstract

The water status of strawberry (Fragaria х ananassa Duchesne) was indicated by the occurrence of guttation. Guttation was present when pre-dawn leaf water potential (PLWP) was greater than -0.07 MPa and absent when PLWP was below – 0.11 MPa. Plants exhibiting guttation had greater stomatal conductivity and lower leaf – air temperature at midday, indicating a greater transpiration rate. Hydathodes on older leaves did not consistently express guttation; thus, the occurrence of guttation must be evaluated on young leaves.

Open Access

In previous work no difference was found in leaf water potential or solute potential between young guttating leaves and older non-guttating leaves of the same plant. This suggested that the absence of guttation in older leaves was associated with a plant resistance component in the hydathodes. Hydathodes of young, folded leaves contained water pores with various apertures and no signs of occlusion.. In expanded, young leaves, production of epicuticular waxes and excretion of some substance through the pores was observed in the hydathode region. By the time leaves had fully expanded the hydathodes had become brownish. The combination of wax deposition and excreted substance had formed plates of solid material covering water pores. These observations suggest that deposition of substances on top of pores contribute to occlusion of water pores in old leaves.

Free access

The objectives of this lysimeter study were to 1) evaluate the amount of dewfall, 2) determine the contribution of dew to daily evapotranspiration (ET) in fall-grown strawberries (Fragaria ×ananassa Duch.), and 3) determine the relationship between actual and potential ET (PET) of strawberry. Dewfall amounts averaged 0.8 mm·day–1 and accounted for 33% of the daily ET during the 27 Sept. to 6 Nov. period. Daily ET was linearly related to PET calculated from the Penman–Monteith equation, with an accuracy of ±3 mm based on lysimeter ET. Daily ET for 2- to 4-day periods was estimated with an accuracy of ±1 mm using the Penman–Monteith. We conclude that dewfall cannot be ignored in the ET of fall-grown strawberries in the mid-Atlantic section of the United States.

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Abstract

Naphthaleneacetic acid (NAA) in a concentration of 1.0% in 10% white latex paint applied to the trunk and crown of muscadine grapevines (Vitis rotundifolia Michx.) at budbreak in the spring effectively inhibited sprout development and did not affect fruit development.

Open Access

Western trailing blackberries (e.g., `Boysen' and `Marion') are grown in Oregon. USDA-released semi-erect thornless blackberries (e.g., `Chester Thornless') and erect, thorny blackberries (e.g., `Cherokee') from Arkansas are grown across the United States from the mid-Atlantic coast region to Oregon. Flower bud development in several blackberry cultivars growing at three sites (Arkansas, Oregon, and West Virginia) was studied. In buds of `Boysen' and `Marion' blackberries from Oregon, sepal primordia were first observed in September and November, respectively. Further floral bud development continued into January. Sepal development in `Cherokee' buds occurred in November in Oregon and in December in Arkansas. At all subsequent sampling dates, the development was more advanced in Oregon than in Arkansas. Buds of `Chester Thornless' blackberry from all three sites remained undifferentiated until spring. Preliminary findings indicated that the time of flower bud initiation varied considerably among the cultivars examined. The results suggest that floral bud development in blackberry, once initiated, is continuous, but periods of low temperature can arrest bud development.

Free access

Postharvest treatment with pyrrolnitrin (250 mg·liter-1) and low storage temperatures delay postharvest rot development in fall-harvested `Tribute' strawberries (Fragaria × ananassa Duch.). Untreated fruit stored at 18C developed gray mold fruit rot (Botrytis cinerea) and rhizopus rot (leak) by the second day. Fruit that did not develop gray mold or leak eventually developed blue mold rot (Penicillium spp.). No rot was observed at 1C, but gray mold and rhizopus rots developed after berries were transferred to 18C. Pyrrolnitrin delayed the appearance of the various rots by 2 to 4 days, but did not reduce the rate of rot development. Chemical name used: 3-chloro-4-(2'-nitro-3'-chlorophenyl)pyrrole (pyrrolnitrin).

Free access