31 research outputs found
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Physiology of flowering in Coffea arabica L. : role of growth regulators and water relations
Coffee trees growing in the Kona district of Hawaii
were treated with different concentrations of either BA,
GA3, or Promalin, and pruned at the time of flowering. No
significant differences in the flowering and fruit ripening
pattern were found. High concentrations (100 mg/1) of
growth regulators decreased fruit fresh weight. Pruning
yielded the lowest number of fruit and flowers, and caused
branch dieback. Fruit set was between 46 and 83% for the
two years studied.
Flower buds from trees growing in the field that were
>4 mm, but not developed to the candle stage at the time of
GA₃ treatment, reached anthesis 20 days earlier than the
controls. Their development was independent of rainfall,
unlike the controls. Fruit from buds that had been treated
at the >4 mm or the candle stage ripened more synchronously
and earlier than the control. Buds smaller than 4 mm did
not respond to GA₃ treatment.
A threshold leaf water potential of -2.7 MPa, and
flower bud water potential of about -4.0 MPa was necessary
to overcome dormancy of flower buds in greenhouse grown
trees. GA₃ stimulated anthesis in some plants that were
stressed to leaf water potentials of -2.1 MPa. Ethylene
evolution of flower buds where dormancy had been broken
with water stress was low, compared to dormant flower buds.
At anthesis, ethylene evolution reached highest levels.
Free and conjugated IAA levels in flower buds changed
markedly after the dormancy breaking stimulus. Doubling
of fresh and dry weight of flower buds occurred 3 to 5 days
after water stressed plants were rehydrated. It was
preceded by an increase in free IAA, and a tripling in the
rate of water uptake from 1 to 3 days after rehydrating
water stressed plants. Throughout the development, the
largest percentage of IAA was present in the conjugated
form
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Frost hardiness of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings raised in three nurseries
Two-year-old Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] seedlings of two seed sources raised in three nurseries in Oregon and Washington were tested for differences in frost hardiness from September 1985 to March 1986. The objective of the study was to determine whether nursery location had an influence on seedling acclimation, deacclimation , budburst and first-year field performance.
Frost hardiness was determined five times from September to December in the nurseries. In January 1986 seedlings were lifted at the three nurseries. Dehardening of potted trees was observed under outdoor and growth chamber conditions. Budburst of the trees dehardening outdoors was recorded from March to June. Hardiness was determined with a whole plant freezing test. Seedlings were frozen at each sampling date to 4 test
temperatures to evaluate needle, bud and stem tissue damage. In general, trees raised in the highest elevation nursery or the most northern nursery had hardier tissue than seedlings raised in the coastal nursery. However, hardiness varied for each tissue and among nurseries and seed sources. In February and March seedlings from the Cascade (975m) seed source were less hardy than seedlings from the coastal source (450m). A growth chamber experiment confirmed the outdoor dehardening pattern.
With a 16 hour photoperiod a constant temperature of +5°C maintained cold hardiness, whereas +10°C and 15°C promoted rapid dehardening after 20 days. To predict hardening, a regression equation with nursery
weather data and elevation was calculated. Photoperiod, number of frost days, and elevation were the most important independent
factors predicting hardening (R²=0.29).
The environment of the three nurseries seemed to have a strong influence on budburst. Trees raised in the coastal nursery
burst bud significantly earlier than trees from the other two nurseries. Mean terminal budburst of potted trees from both seed
sources in each nursery occurred only 2 days apart. Frost hardiness in January and first-year field growth were not
correlated. A correlation between the electrolytic conductivity of shoot tips and the damage of needles, buds, and stems as determined by the whole plant freezing test was poor. The highest correlation coefficient (r) was 0.69. Different hardening rates of tissues and plant to plant variability may have contributed to the low correlation. The conductivity method as outlined in this study does not provide a satisfactory estimation of frost hardiness of
two-year-old bareroot Douglas-fir seedlings
Climate-Ready Landscape Plants: Garden Roses Trialed at Reduced Irrigation Frequency in Utah, USA
Increased urban and suburban populations in the arid western United States have resulted in more water demand; however, water availability in the region has become limited because of inadequate precipitation. Recent droughts have led to restrictions on irrigating landscape plants. Garden rose (Rosa ×hybrida) is commonly used as flowering plants in residential landscapes, but its drought tolerance has not been widely studied. The objective of this study was to determine the impact of reduced irrigation frequency on visual quality, plant growth, and physiology of five garden rose cultivars, including ChewPatout (Oso Easy® Urban Legend®), Meibenbino (Petite Knock Out®), MEIRIFTDAY (Oso Easy® Double Pink), Overedclimb (Cherry Frost™), and Radbeauty (Sitting Pretty™). Twenty-four plants of each rose cultivar were established in a trial plot at Utah Agricultural Experiment Station Greenville Research Farm (North Logan, UT, USA) in Summer 2021. Plants were randomly assigned to one of three deficit irrigation treatments for which irrigation frequencies were calculated using 80% reference evapotranspiration (ETO) (high), 50% ETO (medium), and 20% ETO (low). The total volumes of irrigation water applied to each plant were 345.6, 172.8, and 43.2 L for the high, medium, and low irrigation frequencies, respectively, during the deficit irrigation trial from 12 May to 30 Sep 2022. Root zones were wetted more frequently as irrigation frequency increased from low to high irrigation frequencies. Decreased irrigation frequency increased the number of visibly wilted and damaged leaves on all rose cultivars. However, only ‘Meibenbino’ and ‘MEIRIFTDAY’ exhibited a reduction in overall appearance under decreased irrigation frequency. The relative growth indices of both ‘Meibenbino’ and ‘MEIRIFTDAY’ decreased by 6%, whereas the dry weights of their leaves decreased by 37% and 36%, respectively, as irrigation decreased from high to low frequencies. Roses in this study appeared to decrease stomatal conductance up to 51% when irrigation decreased from high to low frequencies, or when air temperature increased. ‘Meibenbino’ and ‘MEIRIFTDAY’ exhibited unacceptable overall appearance, growth reduction, and higher leaf–air temperature differences, and they were less tolerant to reduced irrigation. Although the ‘Radbeauty’ maintained plant growth under the reduced irrigation frequency, the large leaf size led to a more visibly wilted appearance and the potential for heat stress, thus impairing visual quality. ‘ChewPatout’ and ‘Overedclimb’ were most tolerant to deficit irrigation at 20% ETO and maintained plant growth with acceptable visual quality and lower leaf temperatures when they received one irrigation during the growing season
Climate-ready Landscape Plants: Garden Roses Trialed at Reduced Irrigation Frequency in Utah, USA
Increased urban and suburban populations in the arid western United States have resulted in more water demand; however, water availability in the region has become limited because of inadequate precipitation. Recent droughts have led to restrictions on irrigating landscape plants. Garden rose (Rosa ×hybrida) is commonly used as flowering plants in residential landscapes, but its drought tolerance has not been widely studied. The objective of this study was to determine the impact of reduced irrigation frequency on visual quality, plant growth, and physiology of five garden rose cultivars, including ChewPatout (Oso Easy® Urban Legend®), Meibenbino (Petite Knock Out®), MEIRIFTDAY (Oso Easy® Double Pink), Overedclimb (Cherry Frost™), and Radbeauty (Sitting Pretty™). Twenty-four plants of each rose cultivar were established in a trial plot at Utah Agricultural Experiment Station Greenville Research Farm (North Logan, UT, USA) in Summer 2021. Plants were randomly assigned to one of three deficit irrigation treatments for which irrigation frequencies were calculated using 80% reference evapotranspiration (ETO) (high), 50% ETO (medium), and 20% ETO (low). The total volumes of irrigation water applied to each plant were 345.6, 172.8, and 43.2 L for the high, medium, and low irrigation frequencies, respectively, during the deficit irrigation trial from 12 May to 30 Sep 2022. Root zones were wetted more frequently as irrigation frequency increased from low to high irrigation frequencies. Decreased irrigation frequency increased the number of visibly wilted and damaged leaves on all rose cultivars. However, only ‘Meibenbino’ and ‘MEIRIFTDAY’ exhibited a reduction in overall appearance under decreased irrigation frequency. The relative growth indices of both ‘Meibenbino’ and ‘MEIRIFTDAY’ decreased by 6%, whereas the dry weights of their leaves decreased by 37% and 36%, respectively, as irrigation decreased from high to low frequencies. Roses in this study appeared to decrease stomatal conductance up to 51% when irrigation decreased from high to low frequencies, or when air temperature increased. ‘Meibenbino’ and ‘MEIRIFTDAY’ exhibited unacceptable overall appearance, growth reduction, and higher leaf–air temperature differences, and they were less tolerant to reduced irrigation. Although the ‘Radbeauty’ maintained plant growth under the reduced irrigation frequency, the large leaf size led to a more visibly wilted appearance and the potential for heat stress, thus impairing visual quality. ‘ChewPatout’ and ‘Overedclimb’ were most tolerant to deficit irrigation at 20% ETO and maintained plant growth with acceptable visual quality and lower leaf temperatures when they received one irrigation during the growing season
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Questions to ask when planning to start a wholesale plant nursery
6 pp.The plant nursery business is complex and requires knowledge about the technical aspects of growing plants and managing a business. This publication is an introduction for those interested in starting their own wholesale nursery business. Different types of production systems - container and field production- are discussed as well as the types of plants typically grown in Southwest nurseries. Starting a business involves many decisions that will culminate in the development of a business plan. Resources for new producers include national, regional, and local trade organizations. A worksheet with questions is included to help future operators consider whether they want to start a new wholesale production nursery. Publication AZ1393 Revised 07/2017. Originally published 200
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Poda de arbustos en los desiertos de baja y media elevación de Arizona
La necesidad de podar arbustos que comúnmente se plantan en los en los desiertos de baja y media elevación de Arizona varÃa desde la no poda hasta la poda por temporada. Esto depende según la especie de la planta, el diseño intencionado y la ubicación en el paisaje. Por lo general los arbustos de crecimiento rápido necesitan ser podados frecuentemente desde el momento que son plantados hasta su madurez, mientras que los arbustos de crecimiento lento requieren poca o ninguna poda. La poda sólo debe hacerse cuando sea necesario y durante la época del año adecuada. Utilizar la forma natural de crecimiento del arbusto es una buena guÃa para la poda. Se debe evitar esquilar (recortar) los arbustos, al menos que sea para el mantenimiento de setos formales o esculturas de plantas. La poda debe hacerse con podadoras manuales afiladas o, para tallos más gruesos, tijeras de yunque
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Pruning Shrubs in the Low and Mid-Elevation Deserts in Arizona
Revised; Originally published: 10/200910 pp.This publication presents reasons for pruning, and how and when to prune. Pruning recommendations of individual regional plants are provided and shrubs for formal and informal hedges are listed
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Forcing Containerized Roses in a Retractable Roof Greenhouse and Outdoors in a Semi-Arid Climate
Sales of containerized roses have increased dramatically in recent years and producing flowering plants in containers in a timely manner is important to the nursery industry. An experiment was conducted to determine whether forcing containerized roses will be faster in a retractable roof greenhouse compared to outdoors. Results suggest that forcing roses in a retractable roof greenhouse can shorten the production time and increase quality of finished plants, however, cultivar, time of harvesting, and time in cold storage also affect these parameters
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Drought and Extreme Heat: Plant Responses and Landscape Maintenance Practices
Drought and heat conditions are becoming more common in the southwestern United States with below average annual rainfall, highly variable local and regional rainfall patterns, and warmer than normal temperatures. Drought conditions are characterized by a prolonged period of less than normal rainfall in the environment, or lack of surface or ground water. In arid climates, drought is common as the amount of annual evapotranspiration, the combined loss of water through the soil evaporation and through plant transpiration, is greater than the amount of rainfall. Although many plants are adapted to dry conditions, prolonged drought and varying degrees of severity may cause irreversible damage or mortality to plants, including our native vegetation
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The Benefits of Plants for Human Health in Healthcare Settings
Gardens have multiple health benefits and have been a component of healthcare facilities through the ages. In the last 30 years, the benefits of nature, gardens, and garden views have been studied to document physical and mental health benefits of patients, staff, and visitors. Healing or therapeutic gardens are designed specifically to evoke positive effects on physical, mental, and spiritual health and to address the needs of those visiting the space. In this article, some concepts applicable to gardens in health care settings in the arid Southwest are discussed