<p> The effective management of submersed aquatic macrophytes depends on understanding their reproductive biology. <i>Potamogeton crispus </i> L. (curlyleaf pondweed, Potamogetonaceae) produces numerous asexual propagules that make traditional management difficult. It has spread to roughly half of the counties in California (USA) from alpine habitats such as Lake Tahoe to the tidally influenced Sacramento-San Joaquin Delta. Studies were conducted from May 2012 till October 2012 at the bench and mesocosm scales in Davis and Sacramento, California, to explore the effects of benthic barrier control measures on the propagules (turions) of <i>Potamogeton crispus. </i> The first study examined the effects of three benthic barrier materials (jute, polyethylene and rubber) on turion sprouting. Jute benthic barrier material allows some light and oxygen through the fabric, while polyethylene allows oxygen, but not light. Rubber barrier material blocks light and oxygen exchange. Turion viability, as determined by sprouting, was then assessed post-treatment. Results showed no significant differences at the bench-scale for the untreated control (100% sprouting, SE=0%), jute (100% sprouting, SE=0%), or polyethylene treatments (96.9%, SE=2.1%) (n=16 for all treatments, &alpha; = 0.05). Rubber treatments resulted in 48.4% sprouting (SE= 10.6%; n=16). Results for the mesocosm experiments showed significant differences between the control and the jute and polyethylene treatments (control = 98.4% sprouting, SE= 1.6%; jute = 71.9% sprouting, SE= 4.5%; polyethylene= 70.3% sprouting, SE= 4.7%, n=16 for all treatments). Jute and polyethylene treatments were not significantly different in the mesocosm experiment. The mesocosm experiment with the rubber barrier significantly reduced sprouting (29.7% sprouting, SE= 6.1%; n=16) compared to other treatments. While light had minimal impact on sprouting, anoxia appeared to be the main factor inhibiting sprouting using benthic bottom barriers. Barrier induced anoxic stress combined with herbicides may potentially offer enhanced efficacy. The second study explored enhancement of the impermeable rubber barrier material with dilute acetic acid loaded into cassava starch "pearls". Turions were exposed for two weeks and then assessed for viability via post-treatment sprouting protocol with and without hydrosoil at the bench- and mesocosm-scale. Results for the bench-scale showed that the 20.8 mmol L^&ndash;1 acetic acid treatment was not significantly different (p=.4231) compared to the untreated control (Tukey HDS; p&le;0.05). However, the 41.6 mmol L^&ndash;1 acetic acid treatment was highly significantly different from the control (p-value &lt; 0.0001) at the bench-scale, but did not completely inhibit sprouting (mean sprouting of 31.25% (<i>SE</i>= 11.97)). Complete inhibition of sprouting turions occurred for both experiments at and above acetic acid concentrations of 83.3 mmol L^&ndash;1 (SE= 0). Results showed that tapioca starch saturated with acetic acid and combined with impermeable benthic barriers may offer an effective chemical treatment for the control of <i>Potamogeton crispus.</i> The final study examined hot water exposures under the barriers to kill and inhibit sprouting in turions. Heated water circulated under an insulated benthic bottom barrier may potentially offer a simple non-chemical rapid method to target surface propagules on the sediment, subterranean propagules and young plants. Heated water was used to treat <i>P. crispus</i> turions at the bench and mesocosm scales (25&deg;C, 40&deg;C, 50&deg;C, 60&deg;, 70&deg;C and 80&deg;C exposures for 30 to 300 seconds). Heated water exposures inhibited sprouting turions at 50&deg;C and 60&deg;C at the mesocosm and the bench scales, however, did not completely inhibit sprouting for all time exposures except at the bench-scale 60&deg;C treatment for 300 seconds. For 70&deg;C and 80&deg;C treatment exposures, there was a slight difference at the 30 second exposure mark, but at 60 second and beyond, all 70&deg;C and 80&deg;C treatments provided 100% inhibition. The cost to raise the temperature 60&deg;C from ambient water temperature under the contained limited volume under insulated barriers is estimated to be approximately $2 per 9.3 m² (100 ft²) for 5 minute treatments or $3459 ha^-1 ($1400 acre^-1).</p>

<p> <b>Purpose.</b> The purpose of this research was to examine how inmate horticulture programs have emerged and have been replicated in an effort to rehabilitate individuals, curtail spending, and reduce recidivism. The research explores how food justice and drug policy intersect, examining the roles of classism and racism and taking note of factors influencing recidivism. </p><p> <b>Theoretical Framework.</b> Diffusion of innovation analyzes the adoption of a new idea, technique, product, or service, focusing on how it is communicated and adopted by a social system over a period of time. It is necessary to understand the relationship among culture, values, existing practices, and political/social/environmental climate in order to facilitate the adoption of a new innovation.</p><p> <b>Methodology.</b> The researcher employed a mixed methods research design. The researcher performed a historical review of policies and events that led to the overcrowding of prisons and the criminalization of certain substances. Semistructured interviews were conducted with 10 individuals involved with inmate horticulture programs. Elements included in the study are the variation between programs and their perceived efficacy, challenges, and barriers. </p><p> <b>Findings.</b> Research findings revealed inmate horticulture programs fall into different areas of focus; innovative programs have blended components to provide integrated services. Five primary archetypes were identified: rehabilitative/therapeutic, punitive/labor, vocational, cost savings, and sustainability. Collaboration was crucial in framing the conversation, determining the skillsets of those involved, and the best way to leverage resources. Challenges to diffusing therapeutic inmate horticulture programs stem from social and political inflexibility.</p><p> <b>Conclusions and Recommendations.</b> The social construction of an issue or population impacts the political response, framing of issues, and type of media attention received. The amount of public demand to address the policy issue and federal government involvement influence the adoption and diffusion of innovations. The community benefits from horticulture programs, because former inmates are less likely to commit crimes or victimize people if they have been exposed to rehabilitative programs that prepare them for job opportunities upon release. Well-rounded programs give participants an understanding of food justice, horticulture, leadership, restoration, and healing and access to wraparound services.</p>

A new, uncomplicated system for the forced ventilation of plants and cultures has been investigated in terms of both its efficiency of ventilation and its effects on the growth and physiology of various plant species, including cauliflower, tobacco, Annona (custard apple) and potato. This new system, which has no moving parts or artificial energy requirement, provides a sustained, pressurised stream of sterile, humidified air (RH = 70-94%) driven by humidity-induced diffusion. This process depends upon the maintenance of a gradient of water vapour across a microporous partition for inducing the diffusion of air into the apparatus. Flows up to 5 cm³ min¯¹ can be produced and the atmosphere in a 60 cm³ culture vessel can be renewed every 12 min Compared to the standard conventional diffusive method of ventilation, e. g. by capping the vessel with a polypropylene disc, this new system has proved to be 18X more efficient in removing accumulated ethylene and in keeping CO₂ and O₂ levels in culture vessels close to atmospheric. This forced ventilation system has also been shown to be very effective in the in vitro cultivation of seedlings or cuttings of cauliflower, tobacco, Annona and potato for improving growth and preventing symptoms of vitrification such as leaf epinasty, reduction of leaf area and production of abnormal stomata. In potato cuttings the induction and production of microtubers have been promoted and the growth of abnormal callus prevented. In Annona cuttings flower bud production, leaf and shoot growth and micropropagation have been promoted and leaf and flower bud abscission have been reduced. In cauliflower, tobacco and Annona the leaf chlorophyll contents, rates of photosynthesis and yields were improved by this forced ventilation. These beneficial effects have been variously attributed to the efficient removal of ethylene, the maintenance of near to atmospheric levels of CO₂ and O₂ by day and night and to the reduction of humidity levels in the vessels to below 100% RH. It is hoped that this new ventilation system, which is comparatively inexpensive and requires very little maintenance might have some useful applications in the field of tissue culture and perhaps particularly in developing countries.

No description available.

The horticultural industry is responsible for approximately half of the invasive plant introductions in North America. To reduce these introductions, voluntary initiatives are preferred over government regulations. This thesis aims to evaluate the effectiveness of two types of voluntary initiatives. At the gardener level, I investigated the effectiveness of alternative species promotion campaigns, called “Grow Me Instead” programs. Adult gardeners visiting the Royal Botanical Gardens in Hamilton, Ontario, as well as customers at two garden centres, participated in a conjoint analysis which measured their preferences for various traits of potential ground cover species. Results showed that gardeners generally prefer plant species having invasive characteristics, suggesting these programs may not be as effective as initially believed. At the retailer level, this study aimed to build upon the work done by Burt and colleagues (2007) to obtain further understanding of the relative strength of internal (ethical motivations) and external (legislation, stakeholder pressures and economic opportunities) factors for motivating participation in voluntary initiatives. Telephone interviews were conducted with 30 industry professionals from southern Ontario to assess their adoption of the St. Louis Voluntary Codes of Conduct. Results found that participation rates of industry professionals in southern Ontario were lower for every specific initiative than those interviewed by Burt et al. (2007). Industry professionals presently experience the most pressure to participate from a sense of personal responsibility and the desire to create a green business image. Pressure was significantly higher from these sources than from pressure from employees. Together these two studies identified several barriers to the efficacy of voluntary initiatives as well as some reasons for optimism. To ensure the success of future voluntary initiatives, efforts must be made to encourage these two groups to work together. Understanding how both retailers and gardeners respond to voluntary initiatives will assist in the development of more effective programs and lead to fewer horticultural invasive species introductions in the future.

New Zealand�s main export earnings come from the primary production area including agriculture, horticulture, and viticulture. One of the major contributors in this area of horticulture is the production of quality export grade fruit; specifically apples. In order to maintain a competitive advantage, the systems and methods used to grow the fruit are constantly being refined and are increasingly based on data collected and analysed by both the orchardist who grows the produce and also researchers who refine the methods used to determine high levels of fruit quality. To support the task of data analysis and the resulting decision-making process it requires efficient and reliable tools. This thesis attempts to address this issue by applying the techniques of Connectionist-Based Intelligent Information Systems (CBIIS) for Image Analysis and Knowledge Discovery. Using advanced neurocomputing techniques and a novel knowledge engineering methodology, this thesis attempts to seek some solutions to a set of specific problems that exist within the horticultural domain. In particular it describes a methodology based on previous research into neuro-fuzzy systems for knowledge acquisition, manipulation, and extraction and furthers this area by introducing a novel and innovative knowledge-based architecture for knowledge-discovery using an on-line/real-time incremental learning system based on the Evolving Connectionist System (ECOS) paradigm known as the Evolving Fuzzy Neural Network (EFuNN). The emphases of this work highlights knowledge discovery from these data sets using a novel rule insertion and rule extraction method. The advantage of this method is that it can operate on data sets of limited sizes. This method can be used to validate the results produced by the EFuNN and also allow for greater insight into what aspects of the collected data contribute to the development of high quality produce.

Doctor of Philosophy (PhD) / The Flesh Browning (FB) disorder of ‘Cripps Pink’ apples presents a significant threat to the established market identity of the ‘Cripps Pink’ apple in Australian and export markets. Climatic conditions during fruit growth and development predispose ‘Cripps Pink’ apples to developing the FB disorder during storage. The FB disorder can be classified into two distinct disorders based on their physiological and structural differences and by seasonal climatic conditions. The diffuse type of FB (DFB) is a chilling injury, occurring in districts or seasons accumulating less than 1100 growing degree days (GDD) above 10oC between full bloom and harvest. In these climatic conditions, ‘Cripps Pink’ apples have delayed postharvest ethylene production. Diffuse FB effects fruit cortex tissue and is characterised as cellular collapse. Storing fruit at 3oC can reduce the incidence of DFB. The radial type of FB (RFB) is primarily a senescent disorder, occurring in districts or seasons accumulating greater than 1400 GDD above 10oC between full bloom and harvest. In these climatic conditions, postharvest ethylene production is not delayed. Radial FB affects the cells adjacent to the vascular tissue of the fruit and is characterised by damaged cell walls. Storing fruit at 1oC can reduce the incidence of RFB. Harvest maturity and the level of CO2 in the storage atmosphere are additive influences on the development of RFB. Seasons or districts accumulating more than 1700 GDD have a very low risk for developing RFB. Seasonal climatic conditions can provide a guide for predicting the risk of developing RFB and DFB during storage.

Thesis--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

Thesis--University of Wisconsin. / eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 341-350.

Thesis (MScAgric)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Internal breakdown (internal browning - IB and gel breakdown - GB), over maturity and immaturity are the main factors adversely affecting the quality of exported South African plums. Maturity problems occur when plums are strip harvested, i.e., all the fruit in a block or orchard are harvested once, when the majority of the fruit are at optimum maturity. This results in both ovennature and immature fruit being harvested and contributes to a high percentage of fruit being rejected for export. In general, internal browning occurs when plums are exported under a single 10\,,, temperature regime and gel breakdown occurs when plums are exported under a dual temperature regime. However, GB can also occur at harvest in fruit that are very ripe and may occur at single low temperatures, where it would be masked by lB. While it is known that some cultivars, like 'Angeleno', can withstand a single temperature regime, others cannot. To the best of our knowledge, the reason for this difference is not understood. Many factors affect the quality of plums, including light incidence in the canopy, mineral nutrition and harvest maturity. Plums that were grown on high density training systems such as 'a V- or spindle system yielded consistently high quality fruit with low incidences of gel breakdown. This was in contrast to earlier findings where low-density training systems produced high levels of GB, especially in the lower part of the tree canopy. Branches that were shaded with 80% shade netting yielded fruit with high levels of GB, indicating that the main effect of improved canopy structure on quality was improved light management. A postharvest boron application on 'Songold' plums prior to storage had no effect on the incidence of intemal breakdown in the fruit, but did damage the cuticle, resulting in severe shrivel. However, internal conductivity and firmness measurements indicated that there was some effect of the boron on cell membranes. A more thorough investigation of pre- and postharvest application of boron is recommended in order to determine whether there could be a positive effect of boron in improving fruit quality in plums. Four cultivars of plums ('Pioneer', 'Sapphire', "Songold ' and 'Angeleno') were harvested throughout, and extending beyond, the commercial harvesting period. In all cultivars, the drop in firmness between harvests was not as great as expected and the later harvested fruit were of a similar, if not superior, quality as compared to the earlier harvested fruit. Later harvested plums tended to have higher TSS and better colour development. Contrary to what was expected, later harvested fruit did not have more internal disorders than earlier harvested fruit. This indicates the importance of harvesting at optimum maturity. 'Angeleno' plums had no internal disorders, even after five weeks of cold storage at a single low temperature. 'Pioneer' and 'Sapphire' plums were classified as climacteric and 'Songold' and 'Angeleno' were classified as suppressed climacteric based on ethylene production. The climacteric plums respired and produced ethylene at a higher rate than the suppressed climacteric plums. Climacteric plums ripened faster during shelf life than suppressed climacteric plums. Furthermore, while climacteric plums did not need a cold storage period prior to ripening, suppressed climacteric plums needed a cold storage period in order to ripen normally. The longer the cold storage period prior to transfer to higher temperatures, the faster the plums ripened and the higher the ethylene production at the higher temperature. The suppressed climacteric genotype could possibly be incorporated into plum breeding programs in order to extend the storage period and shelflife of new plum cultivars. The long storage times required to ship plums from South Africa to the export markets has necessitated research on postharvest physiology and quality of this fruit. The use of the climacteric and suppressed climacteric system to classify fruit is expected to assist in understanding the different physiological responses of the cultivars and assist in developing handling protocols. Preharvest factors, particularly light and nutrition, also playa role in postharvest quality. / AFRIKAANSE OPSOMMING: Interne verval (interne verbruining en gelverval), oorrypheid en onryp vrugte, is die hoof faktore wat die uitvoer van Suid Afrikaanse pruime negatief beïnvloed. Rypheidsprobleme ontstaan wanneer pruime gestroop-oes word, met ander woorde, al die vrugte in 'n blok of boord word geoes wanneer die meerderheid vrugte optimum rypheid bereik het. As gevolg hiervan word 'n groot persentasie vrugte vir uitvoer afgekeur, omdat hulle te ryp of nie ryp genoeg is nie. Oor die algemeen vind interne verbruining plaas wanneer vrugte onder 'n enkel lae temperatuur uitgevoer word en gelvervel vind plaas wanneer vrugte onder 'n dubbele temperatuur regime vervoer word. Gel verval kan egter in baie ryp vrugte by oes voorkom en mag by enkel lae temperature voorkom .waar dit deur interne verbruining gemaskeer sal word. Kultivars soos 'Angeleno' kan onder enkel lae temperatuur uitgevoer word sonder interne probleme, terwyl ander pruimkultivars me so uitgevoer kan word nie. So ver ons weet, word die rede hiervoor nie goed verstaan nie. Daar is baie faktore wat die kwaliteit van pruime beïnvloed, onder meer lighuishouding, minerale voeding en die rypheid waarby die pruime geoes word. Pruime wat in hoë-digtheid sisteme soos 'n V- of "spindle" groei het goeie kwaliteit vrugte met 'n lae persentasie gelverval gelewer. Dit is in teenstelling met vroeër bevindinge, waar vrugte van lae digtheid boorde hoë persentasies geverval gelewer het, veral in die onderste gedeeltes van die boom. Takke wat met 80% skadunet bedek is het hoër persentasies gelverval as die kontrole gelewer, wat aandui dat die hoof effek van die verbeterde boom struktuur op kwaliteit, verbeterde lighuishouding was. 'n Na-oes aanwending van boor op 'Songold' pruime het geen effek op die voorkoms van gelverval gehad nie, maar het die kutikula beskadig en tot hoë persentasies verrimpeling gelei. Fermheid en inteme weerstand lesings het egter getoon dat daar wel 'n effek van die boor op die selmembrane en selwande was. 'n Meer omvattende ondersoek van voor- en na-oes aanwending van boor word aanbeveel om vas te stelof daar wel 'n positiewe effek van boor in die verbetering van pruim kwaliteit is. Vier pruim kultivars, ('Pioneer', 'Sapphire', 'Songold' en 'Angeleno'), is gedurende, sowel as later as die kommersiële oesperiode geoes. In al die kultivars was die afname in fermheid kleiner as wat verwag is, en vrugte wat later geoes is het dieselfde, en soms beter, kwaliteit as die vrugte wat vroeër geoes is gehad. Pruime wat later geoes is het beter kleur en gewoonlik hoër suikers gehad. In teenstelling met wat verwag is, het pruime wat later geoes is nie meer interne verval gehad as die pruime wat vroeër geoes is nie. Dit dui die belangrikheid van optimale oesrypheid aan. 'Angeleno' het geen interne verval gehad nie, selfs na vyfweke opberging by -0.5°C. 'Pioneer' en 'Sapphire' pruirne is as klimakteries en 'Songold' en 'Angeleno' as onderdrukte klimakteries geklassifiseer, gebaseer op etileen produksie. Die klimakteriese pruime het teen 'n hoër tempo gerespireer en etileen geproduseer as die onderdrukte klimakteriese pruime. Gedurende raklewe het klimakteriese vrugte vinniger as onderdrukte klimakteriese vrugte ryp geword. Verder, terwyl klimakteriese pruime nie opbgerging by 'n lae temperatuur nodig gehad het nie, het onderdrukte klimakteriese vrugte welopberging by 'n lae temperatuur nodig gehad om normaal ryp te word. Hoe langer die koel opbergingsperiode was, hoe vinniger het die pruime ryp geword by raklewe en hoe hoër was hulle etileen produksie. Die onderdrukte klimakteriese genotipe kan moontlik in teelprogramme geïnkorporeer word om kultivars met verlengde opbergings- en raklewe te teel. Die lang vervoer tye wat benodig word om Suid Afrikaanse pruime by die uitvoer markte te kry het dit nodig gemaak om navorsing oor die na-oes fisiologie en kwaliteit van pruime te doen. Die klassifisering van pruime as klimakteries of onderdrukte klimakteries kan ons in staat stelom die verskillende fisiologiese reaksies van die kultivars te verstaan en om hanterings prosedures te ontwikkel. Voor-oes faktore, veral lighuishouding en mineraalvoecling speelook 'n rol in na-oes kwaliteit van pruime.