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- Author or Editor: N. C. Peterson x
Ficus benjamina were treated with ancymidol [α-cyclopropyl-α- (p- methoxyphenyl)-5-pyrimidine methanol] as a soil drench using 1.0 mg/15-cm pot plus 200 ppm spray. Plants were exposed to dark storage treatments (0, 4, 8, and 12 days) in shipping boxes before being held 4 months in a simulated interior environment (SIE) under 15 μE m−2s−1 photosynthetically active radiation (PAR) from incandescent (INC) lamps or Cool White fluorescent (CWF) lamps. Leaf drop was less for ancymidol-treated plants for all dark storage periods in comparison to untreated plants. In addition, leaf drop was less on plants held in SIE 4 months under INC lamps. Ancymidol-treated plants had better plant grade for all dark storge periods than untreated plants when held under both lamp sources and were superior under INC lamps.
Ficus benjamina was maintained 10 weeks in a simulated interior environment (SIE) with a controlled temperature of 21°C ± 1° under either 15 µEm-2sec-1 photosynthetically active radiation (PAR) from Cool White fluorescent (CWF) lamps or 15 µEm-2sec-1 (PAR) from incandescent (INC) lamps after receiving no light for various time periods (0, 4, 8 and 12 days). Plants held under CWF had a decrease in chlorophyll content and increase in leaf drop with increased days in dark. Quality as determined by leaf retention and plant grade indicated that those plants receiving 8 and 12 days dark storage and held under CWF lamps lost more leaves and were not salable after 10 weeks in SIE. Most plants held under INC lamps had no decrease in chlorophyll content, retained more leaves, and maintained good plant grade regardless of days in dark storage.
In vitro growth of white potato (Solanum tuberosum L.) cv. Norland was investigated comparing two types of culture vessel enclosures. Nodal cuttings were aseptically transferred to 25 × 150 mm glass culture vessels containing a solidified medium consisting of Murashige and Skoog salts, 1% sucrose, and pH adjusted to 5.8. The vessels were capped with loose-fitted (1 cm gap between the top of the vessel and the top of the cap) Magenta 2-way caps or Bellco Kap-uts with calculated air changes hr-1 of 2.25 and 1.43, respectively. Instantaneous PPF attenuations of 15% for Magenta caps and 23% for Bellco caps were also measured. The cultures were maintained for 28 d in an environmental growth chamber under Daylight fluorescent lamps with a 16 hr light/8 hr dark photoperiod, 200 μmol m-2s-1 PPF maintained for each cap type, constant 23 C, 65% relative humidity, and CO2 enrichment of 1000 μmol mol-1 external to the culture vessels. Results showed that increased plantlet height, fresh weight, and dry weight was obtained for plantlets cultured with Magenta caps. The differences in growth and internal CO2 concentration of the vessels correlated well with the difference in air exchange rates, suggesting that increased air exchange of culture vessels resulted in increased mixotrophic plantlet growth.
Leaf abscission was promoted in Ficus benjamina L. (weeping fig) by withholding water from plants growing in sand and by the addition of polyethylene glycol 6000 to hydroponically-grown plants. Leaf shedding occurred when plant water potential decreased below about −6 bar in sand and below −3.5 bar in water culture. Shoot and root environmental conditions modified the water status of plants. Leaf shedding can be dramatically reduced by manipulating environmental conditions to maximize water absorption and minimize transpiration.
Relationships were examined among water deficits, ABA content of leaf tissue, and leaf abscission in intact Ficus benjamina L. (weeping fig). Water deficits were imposed by withholding water from plants growing in sand and by raising the osmotic potential of water culture solutions through the addition of PEG 6000. Unconjugated ABA was quantitatively analyzed using gas chromatography. A strong inverse linear correlation existed between ABA content of leaves and plant water potential. No relationships between ABA content and leaf abscission were observed. ABA content in leaves collected from plants growing in a greenhouse, having a plant water potential of −0.5 bar, was about 75 fold greater than the ABA content of leaves collected from plants maintained in a controlled environment room, having plant water potentials of −8.0 bar. Results indicate that ABA does not independently regulate leaf abscission in Ficus benjamina.
‘Idlewild’ peach [Prunus persica (L.) Batsch] was released by the Louisiana Agricultural Experiment Station to provide a 500- to 600-hr chilling-requirement cultivar which produces a good quality fruit. ‘Idlewild’ produces a heavy crop of medium to large semi-freestone fruit that ripen 36 days before ‘Elberta’ or about June 9 in southeastern Louisiana. ‘Idlewild’ has exhibited good resistance to bacterial leaf spot [Xanthomonas campestris pv. pruni (Smith 1903) Dye 1978] when grown under southeastern Louisiana conditions.