The effects of water stress and GA, on breaking dormancy of flower buds of coffee (Coffea arabica L.) were investigated. In the first experiment, water was withheld until the trees reached leaf water potentials (WP) of -1.20, - 1.75, -2.65, or -3.50 MPa. Water potential, ethylene production, and ion leakage of flower buds and leaf disks were examined from release from water stress until anthesis. Trees that had experienced leaf WP of less than - 2.65 MPa, and flower bud WP of about - 4.0 MPa flowered within 9 days after irrigation. In flower buds where dormancy had been broken with water stress, ethylene production was low compared to dormant buds and flowers at anthesis. In the second experiment, O, 50, 100, or 200 mg GA3/liter was painted on branches of nonstressed trees. In experiment three, water was withheld until plants reached leaf WP of -0.6, -1.3, - 2.1, or - 3.0 MPa, then two branches per tree were painted with O, 50, and 100 mg GA3/liter. Gibberellic acid partially compensated for insufficient water stress to initiate flower opening. Ethylene evolution of flower buds was affected by water stress but not by GA3 treatment. Severe water stress treatments and GA, treatment (200 mg·liter-1) increased ethylene evolution of leaf disks. Ion leakage of flower buds and leaf disks was increased by severe water stress. Ion leakage of flower buds was highest at anthesis. After water stress, dormant and nondormant flower buds at the 4-mm stage could be distinguished based on their ethylene evolution. Chemical name used: gibberellic acid (GA3).
Ursula K. Schuch, Leslie H. Fuchigami, and Mike A. Nagao
Ursula K. Schuch, Leslie H. Fuchigami, and Mike A. Nagzao
Floral initiation in coffee has been shown to be stimulated by short days in young plants, but the inductive stimulus for mature plants is still not clear. Experiments were conducted to determine whether floral initiation in immature and mature plants is promoted by short photoperiods, and delayed by long photoperiods. In a growth chamber study, 18-month-old coffee (Coffea arabica L. cv. Guatemalan) plants exposed to 8 hr photoperiods developed flower buds after 4 weeks, whereas no floral initiation was observed on the plants exposed to 16 hr photoperiods for ten weeks. Trees growing in the field were illuminated with incandescent light from midnight to 3:00 a.m. from July to December 1989. The control plants received no artificial light during the same time period. Night light interruption delayed flower initiation until the end of December on branches that were fully exposed to the light. On control trees, flower buds started to emerge at the beginning of November. These results indicate that in immature and mature coffee plants floral initiation is stimulated by short days, and delayed by long days.
Ursula K. Schuch, Jack J. Kelly, and Trent Teegerstrom
Capillary mats and overhead sprinkler irrigation were used in a simulated retail environment to maintain annual and perennial plants in containers for various time periods during summer and winter. Combining the results from both seasons, four species with dense canopies had larger canopy sizes when maintained on the capillary mats, three species requiring more drainage had larger canopies with overhead irrigation, and five species were unaffected by irrigation systems. Substrate electrical conductivity was higher for some species in winter for plants on capillary mats, conserving fertilizer compared with overhead irrigation. Most species tolerated either irrigation system well. Water application was 71% less in summer and 62% less in winter to maintain plants on capillary mats compared with overhead irrigation. An economic analysis compared the investment required for setup and maintenance of plants in a retail situation using hand watering, overhead sprinkler, or capillary mat irrigation. The partial budget indicates that capillary mats are a labor-saving alternative to hand watering in a retail nursery and will compensate for the higher initial investment within less than 1 year. The overhead sprinklers are the most cost-effective system of the three because of less costly initial set-up and maintenance than the capillary mats; however, they are not a true alternative to hand watering in a retail situation because they interfere with customer traffic and worker activities.
Hannah M. Mathers, Alejandra A. Acuña, Donna R. Long, Bridget K. Behe, Alan W. Hodges, John J. Haydu, Ursula K. Schuch, Susan S. Barton, Jennifer H. Dennis, Brian K. Maynard, Charles R. Hall, Robert McNeil, and Thomas Archer
The U.S. nursery and landscape industry generates 1.9 million jobs and had an annual payroll of greater than $3 billion in 2002, yet little is known about nursery and landscape workers. This lack of information is even more pressing considering that labor generally accounts for greater than 40% of production costs and 31% of gross sales. Labor shortages, immigration reform, and legal status of employees are widely reported as the industry's most critical issues. We hypothesized that relevant data regarding the nursery industry workforce may raise an appreciation of the industry's diversity, increase political power and public awareness, and help stakeholders evaluate policy decisions and plan corrective strategies in a more informed manner. A total of 4466 self-administered questionnaires were sent in 2006, attempting to reach 30 nurseries in each of nine states with 1561 returned (35% response rate). Hispanics constituted 70% of the average nursery workforce, including general laborers (76%), crew leaders (61%), and sales/managers (others) (21%). Across firms, labor retention was less than 51% after 5 years and only 22% of employees understood English, raising questions regarding availability and access to training. Sixty percent of nursery employees had not received work-related training, although 81% of men and 72% of women were interested, and an association between training and employee retention existed. The highest rated training topic of interest was English/Spanish (respective of Spanish/English primary language respondents). There was a positive correlation between developing fluency and worker turnover, making the laborer attrition rate even more unfavorable for employers who not only lost employees with acquired experience, but also with acquired English skills.