environmental regulation, customer-perceived value of the practice in question, grower attitudes toward the practice, and grower demographic characteristics. Environmental regulations. Environmental regulations are environmental laws imposed by state and
Tanya J. Hall, Jennifer H. Dennis, Roberto G. Lopez, and Maria I. Marshall
I.E. Yates and Darrell Sparks
Detached anthers and pollen of pecan [Carya illinoinensis (Wangenh.) C. Koch] were exposed to a range of relative humidities (RH) and/or temperatures to assess the interaction of these environmental factors on pollen dispersal and germination. Dehiscence of anthers was evaluated at selected time intervals following exposure to ≈56%, 33%, 64%, and 97% RH at 10, 21, 27, and 33C in a factorial experiment. Pollen release increased as RH decreased and temperature increased for detached anthers under laboratory conditions and for attached anthers under field conditions. Inhibition of anther dehiscence by high RH could be overcome or minimized with high temperatures and inhibition by low temperatures, in most cases, with low RH. Temperature effects on specific phases in the pollen germination process were evaluated in a sequence of experiments. First, pollen rehydration temperature was varied (3, 15, 29, 33, and 42C) and incubation temperature during tube development kept constant at 25C. After 2 hours of rehydration, tube formation was maximized at 15C and tube length at 29C. Second, all pollen was rehydrated at a constant temperature (25C) and the incubation temperature during tube development varied (3, 15, 29, 33, and 42C). The temperature for maximum tube formation (15C) was different from that for maximum tube length (33C). Morphology of pollen tubes was normal under all rehydration conditions; but, during incubation for pollen tube development, tubes did not develop at 3C and developed abnormally at 42C. The adverse effect on tube development at 3C, but not at 42C, could be reversed by transferring pollen to 25C.
Calin O. Marian, Atilla Eris, Stephen L. Krebs, and Rajeev Arora
The influence of photoperiod and temperature on the seasonal (fall to winter) cold acclimation and accumulation of a 25 kDa dehydrin in Rhododendron `Chionoides' was studied by exposing two groups of plants each in the greenhouse or outdoors to either a natural photoperiod (or short days) or an extended photoperiod (or long days) regime. Results suggest that the shortening daylength alone is sufficient to trigger both the first stage of cold acclimation and concomitant 25 kDa dehydrin induction. Exposure of the plants to natural photoperiod and temperatures induced the greatest cold hardiness and 25 kDa accumulation, while exposure to extended photoperiods (long days) and warmer temperatures (in the greenhouse) failed to induce any significant freezing tolerance in leaves. Whereas short days trigger the cold acclimation process initially, low inductive temperatures can eventually replace the photoperiod stimulus. Seasonal accumulation of 25 kDa dehydrin, on the other hand, appears to be predominantly effected by short photoperiods. Data indicated that the leaf water content of outdoor plants maintained under natural photoperiod was lower than that of plants grown under extended photoperiod. This was also true for the greenhouse plants at the first (September) and the last (January) sampling. It is hypothesized that early 25 kDa dehydrin accumulation may be due to short-day-induced cellular dehydration. Accumulation of two other dehydrins of 26 kDa and 32 kDa molecular masses does not appear to be associated with short day (SD)-induced first stage of cold acclimation. Results show that their accumulation may be regulated by low, subfreezing temperatures and may be associated with the second and/or third stage of cold acclimation of `Chionoides' rhododendron leaves.
Jennifer H. Dennis, Roberto G. Lopez, Bridget K. Behe, Charles R. Hall, Chengyan Yue, and Benjamin L. Campbell
container types used, and 10 open-ended questions based on demographic and industry priorities. It asked respondents about the importance of sustainability, views of state environmental regulations, sustainable practices in place, sustainable practices they
Rhuanito Soranz Ferrarezi, Geoffrey Matthew Weaver, Marc W. van Iersel, and Roberto Testezlaf
environmental impact. Recycling and reuse of unused fertilizer solution prevents the unwanted release of nutrient-rich runoff into the environment, which helps growersmeet environmental regulations. Subirrigation is currently used largely for ornamental plants
Jose Linares, Johannes Scholberg, Kenneth Boote, Carlene A. Chase, James J. Ferguson, and Robert McSorley
environmental regulations ( Athearn, 2004 ). Because excessive use of potentially harmful agrochemicals may affect biodiversity, environmental quality, food safety, and farmers' health, there is increased interest in more sustainable production systems
State and federal regulations relevant to compost marketing and end use can greatly affect the success of a compost distribution and marketing program. Typically, regulations are feedstock-specific and they vary from state to state. They address health, safety, and environmental issues, as well as other concerns of the general public and professional end users. This presentation reviews regulatory approaches adopted by states that are leaders in compost production. It provides insight as to regulatory trends and discusses how they have affected market development to date. Suggestions regarding the improvement or modification of environmental regulations and USDA Acts are also provided.
Jing Zhou, PingPing Li, JiZhang Wang, and Weiguo Fu
( Hikosaka et al., 2006 ). Light and temperature interactions provide crucial information for optimizing environmental regulations under various seasonal conditions ( Franklin et al., 2014 ; Lu et al., 2017 ). Romaine lettuce ( Lactuca sativa L.) is the
A.P. Papadopoulos, J.L Shipp, W.R. Jarvis, T.J. Jewett, and N.D. Clarke
Greenhouse crop production technology is advancing rapidly, and the management of greenhouse crops has become increasingly difficult. Computerized environment and fertigation control of greenhouse crops grown in soilless media offer opportunities for unparalleled manipulation of crop growing conditions. However, the optimization of crop growing conditions for maximum productivity must be practiced with an eye on environmental regulations; worker health concerns; consumer demands for safe food; and ultimately on energy, water, fertilizer, and pesticide use economy. Managing the complex greenhouse cropping system requires a multidisciplinary approach that integrates pest and disease protection strategies with routine cultural practices and environmental and fertigation regimes into a common decision-making process or Integrated Crop Management strategy. This poster describes an Expert System for greenhouse cucumber management based on a general model of Integrated Crop Management for greenhouse crops.