English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Wilting during shelf life is a major cause of postharvest shrink for bedding plants shipped long distances from production greenhouses to retail outlets. The objective of this research was to determine if irrigation at lower, constant substrate moisture content (SMC) during greenhouse production would be a feasible way to acclimate plants for reduced shrinkage during shelf life while potentially conserving irrigation water. In two separate experiments conducted in the fall and spring seasons, rooted plugs of Angelonia angustifolia ‘Angelface Blue’ (angelonia) were grown in greenhouse production until a marketable stage in substrates irrigated at SMC levels of 10%, 20%, 30%, and 40% using a controlled irrigation system. At the end of the greenhouse production stage, plants were irrigated to container capacity and subjected to a simulated shipping environment in shipping boxes in the dark for 2 days. After shipping, plants were placed back in the greenhouse and watered minimally to simulate a retail environment. Data were taken at the end of each stage, i.e., greenhouse production, simulated shipping, and simulated retail. Results indicated that as SMC decreased from 40% to 10%, plants were shorter in height but had proportional and more compact flowering sections. The volume of water received by the 40% SMC plants was three times greater (fall) and 12 times greater (spring) than the 20% SMC plants during greenhouse production and two times greater (fall) and nine time greater (spring) during simulated retail. During production, midday water potentials decreased as the SMC levels decreased, but at the end of the simulated retail, the midday water potentials were the same, suggesting that plants that were drought-stressed during production were acclimated to lower water levels experienced in retail settings. Overall, the 20% SMC treatment produced the best postharvest quality plant resulting from reduced plant height without detrimental effects on flowering. The results demonstrate that while conserving water, controlled irrigation at a lower SMC can produce high-quality plants that have equal shelf life to those that are irrigated at high levels. Retail environments for marketing floriculture crops have a wide range of light levels and temperature. One common characteristic is that irrigation is almost never optimum as a result of untrained personnel or understaffing. Watering practices at retail venues may be indiscriminate, i.e., all plants are watered on the same time schedule regardless of their need resulting in some plants being overwatered and some underwatered. Conversely, watering may be limited, i.e., plants are allowed to wilt before they are watered. Either watering regimen is detrimental to plant health and hastens their decline in postharvest quality and shelf life at the retail level. Hardening off, or toning, at the end of the greenhouse production cycle by reducing fertilizer rate, temperature, light intensity, and soil moisture levels is a practice that has long been known to increase shelf life of floriculture crops such as chrysanthemum (Chrysanthemum indicum), poinsettia (Euphorbia pulcherrima), and other bedding plants (Jones, 2002). Reduced end-of-production fertilization resulted in higher quality ratings for an additional week for bracteantha (Bracteantha bracteata), nemesia (Nemesia ·hybrida), and sutera (Sutera hybrida) and extended flower retention for two argyanthemum (Argyranthemum frutescens ‘Comet White’ and ‘Sunlight’) cultivars during simulated retail (Beach et al., 2009). Reducing irrigation volume during the entire greenhouse production cycle rather than only at the end of production may serve to acclimate floriculture crops to drought stress during marketing. For example, when irrigation was withheld in salvia (Salvia splendens) and vinca (Catharanthus roseus) until wilting for two consecutive drying cycles, both species had a higher water use efficiency (WUE) during the second drying cycle compared with the first, indicating a physiological acclimation of the plants (Nemali and van Iersel, 2004). By comparing four water levels applied throughout production of two cultivars of potted miniature roses (Rosa ·hybrida ‘Charming’ and ‘Bianca Parade’), it was found plants were better able to survive periods of inadequate water during postproduction when water consumption was lower during production (Williams et al., 2000). Rose plants watered at the highest water level had higher water contents but tended to wilt sooner than plants grown with reduced water. Petunias (Petunia ·hybrida) grown at three irrigation frequencies during production and then evaluated in three postproduction temperatures (10/10, 20/20, or 30/20 C day/night) declined in quality most rapidly and had the greatest number of senesced flowers in the moderate and warm postproduction environments when they had been irrigated at the highest frequency. Conversely, plants irrigated less frequently had slower flower development but had reduced number of senesced flowers, greater dry weight, and an overall better visual quality regardless of postproduction temperature to plants irrigated more frequently (Armitage and Kowalski, 1983). Greenhouse irrigation systems have become more efficient in water conservation while still maintaining floriculture crop quality. Constant SMC was reliably maintained for impatiens (Impatiens walleriana), petunia, salvia, and vinca for an extended period of time despite varying plant sizes with little to no runoff and wastage of water (Nemali and van Iersel, 2006). By maintaining SMC, the irrigation system effectively replaced the water that was lost by evapotranspiration, thus creating a plant-driven system (Burnett and van Iersel, 2008). This type of irrigation system could make it easier for growers to limit water during production to only that needed by the plant to maintain quality and plant health that is sustainable throughout the market channels. The objective of the present research was to determine the effect of four levels of constant SMC during greenhouse production followed by one of two postproduction irrigation regimens during simulated retail: 1) indiscriminate (all plants watered the same); or 2) limited (plants allowed to wilt before watering) on growth and subsequent shelf life of angelonia (Angelonia angustifolia) ‘Angelface Blue’. Our hypothesis was that lower, constant SMC during greenhouse production would acclimate or ‘‘condition’’ plants for the two simulated retail watering regimens while conserving irrigation, fertilization, and plant quality during production and marketing. Materials and Methods Rooted cuttings of angelonia ‘Angelface Blue’ were obtained from a commercial propagator (EuroAmerican, Bonsall, CA) and graded for uniformity. Sixteen 16-L (28.1 cm wide, 45.7 cm long, 18.3 cm deep) plastic containers (Iris USA Inc., Pleasant Prairie, WI) were used to hold root substrate (Sunshine LC1 mix; SunGro Horticulture, Bellevue, WA) rather than commercial pots. These containers were necessary to accommodate the size of the Received for publication 26 Aug. 2014. Accepted for publication 14 Nov. 2014. To whom reprint requests should be addressed; e-mail tstarman@tamu.edu. 272 HORTSCIENCE VOL. 50(2) FEBRUARY 2015 Acclima time domain transmissometry sensors (5.4 cm wide, 20.3 cm long, 1.4 cm deep) (Acclima, Inc., Meridian, ID). The exterior surface of each container was sprayed with silver paint to restrict light penetration and algae growth within the containers. Additionally, holes were drilled at the bottom of each container to allow drainage. Fifty-four grams (2.6 kg·m) of 15N–3.9P–9.9K slow-release fertilizer (Osmocote, Peters Professional; Scotts-Sierra, Marysville, OH) were incorporated evenly throughout the substrate before planting. Two dribble ring emitters with a flow rate of 5.3 mL·s (24-inch lead, 6-inch diameter) (Dramm Cooperation, Manitowoc, WI) were placed on top of the substrate and around the plants and secured with greening pins to deliver irrigation. Plants were grown in a glass wall and polycarbonate roof greenhouse in College Station, TX, for two experiments: 1) fall (3 Sept. to 29 Oct. 2010); and 2) spring (25 Jan. to 11 May 2011). Air temperature and solar radiation were measured at plant canopy level using data loggers (WatchDog; Spectrum Technologies, Plainfield, IL) every hour and averaged into daily measurements. Temperature set points for the greenhouse were 24 C day/18 C night. Average temperature in the greenhouse was 25.8 C day/23.1 C night (fall) and 23.2 C day/20.9 C night (spring) for the greenhouse production stage. Average light levels were 14 mol·m·d (fall) and 7 mol·m·d (spring). Average temperatures for the greenhouse during simulated retail were 24.5 C day/22.3 C night (fall) and 23.7 C day/21.9 C night (spring) and average light levels were 5 mol·m·d (fall) and 12 mol·m·d (spring). The greenhouse production stage was initiated by transplanting angelonia plants into the containers and drenching the root substrate with a fungicide to prevent root rot (Banrot, Peters Professional; Scotts-Sierra). Containers were allowed to dry down to their respective SMC treatment levels and those levels were held throughout production until plants were flowering and deemed marketable, i.e., they displayed full foliage and had three flowering stems. To give time for water to travel through the root substrate, the soak cycle was set to water for 30 s with an interval length between watering of 4 min. This allowed water to percolate through the substrate, thus preventing underestimating SMC reading and excess water from being applied. Treatments. Two experiments were conducted, in Fall 2010 (3 Sept. to 29 Oct.) and in Spring 2011 (25 Jan. to 11 May) using similar greenhouse production and simulated shipping practices but with two different irrigation regimens (indiscriminant in fall and limited in spring) during simulated retail. Each experiment

Substrate Moisture Content Effects on Growth and Shelf Life of Angelonia angustifolia