The Effect of Elevated Root Zone Temperatures of Various Duration on Growth and Development of Several Poinsettia Cultivars

Wulster, George J.; Jänes, H.

doi:10.17660/actahortic.1984.148.109

Cited by 4 publications

(3 citation statements)

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“…Similarly, an accelerated rate of flowering with increased root-zone temperature has been reported for poinsettia, chrysanthemum, peace lily (Spathiphyllum sp. ), african violet, and tomato (Brown and Ormrod, 1980;Janes et al, 1981;Vogelezang, 1988Vogelezang, , 1992Wulster and Janes, 1984). For example, TTF of chrysanthemum 'Improved Mefo' was 84 and 99 d when plants were grown at a day/night temperature of 16/11°C with RZH of 25°C or without RZH, respectively (Brown and Ormrod, 1980).…”

Section: Resultsmentioning

confidence: 99%

Bench-top Root-zone Heating Hastens Development of Petunia under a Lower Air Temperature

Olberg¹,

López²

2017

horts

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Heating accounts for up to 30% of total operating costs for greenhouse operations in northern latitudes. Growers often lower air temperatures for production to reduce energy costs; however, this causes delays in development even in cold-tolerant crops, such as petunia (Petunia ×hybrida). This delay increases production time and can reduce profitability. Recent studies on low air temperature bedding plant production indicate petunia as a strong potential candidate for using lower air temperatures in combination with bench-top root-zone heating (RZH) to avoid or reduce delays in development. The objectives of this study were to 1) quantify time to flower (TTF) of seven petunia cultivars and two recombinant inbred lines (RILs) when the mean daily air temperature (MDT) was lowered by 5 °C and bench-top RZH was used and 2) determine if a high-quality petunia crop can be produced on RZH. Petunia ‘Sun Spun Burgundy’, ‘Sun Spun Lavender Star’, ‘Sanguna Patio Red’, ‘Potunia Plus Red’, ‘Potunia Plus Purple’, ‘Supertunia Red’, ‘Supertunia Bordeaux’, and two RILs, IA160 and IA349, were grown in a greenhouse with an MDT of 15 °C without RZH or with a RZH set point of 21, 24, or 27 °C. Additionally, a commercial control (CC) was established by growing plants without RZH at an MDT of 20 °C. All plants were grown under a 16-hour photoperiod to provide a daily light integral (DLI) of ≈12 mol·m−2·d−1. Time to flower was shorter at higher RZH set points. For example, TTF of ‘Potunia Plus Red’ was 56, 52, 49, or 47 days for plants grown at an MDT of 15 °C without RZH, or with RZH set points of 21, 24, or 27 °C, respectively. When a RZH set point of 27 °C was employed, TTF of all cultivars and inbred lines, except ‘Potunia Plus Red’ and ‘Sanguna Patio Red’, was similar to plants grown in the CC. Shorter stem length, lower growth index, and smaller shoot dry mass (SDM) at flowering were observed for plants grown under lower air temperatures with RZH, resulting in a more compact and high-quality plant. Producing a compact plant in a shorter time period is beneficial for growers; thus, results suggest that MDT can be lowered to 15 °C for petunia production when a RZH set point of 27 °C is employed.

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Section: Resultsmentioning

confidence: 99%

Bench-top Root-zone Heating Hastens Development of Petunia under a Lower Air Temperature

Olberg¹,

López²

2017

horts

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“…However, under long days they observed decreased branching and increased stem elongation when the root one was heated. Wulster and Janes (1984) This study was conducted to quantify in situ temperature changes in the canopy and potting medium (root zone) microenvironments under two day/night air temperature regimes, and to determine the response of two poinsettia cultivars to these environments.…”

mentioning

confidence: 99%

“…Root zone heating during the day reduces the canopy-root-zone temperature difference, reducing the magnitude of the stem elongation response. Thus, (-) DT-NT regimes (Erwin et al, 1989a;Moe and Heins, 1990), and continuous (24 h) root zone heating under (+) DT-NT regimes (Janes and Mc-Avoy, 1983;Wulster and Janes, 1984), may produce similar plant growth responses by regulating separate mechanisms controlling the stem elongation response.…”

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confidence: 99%

In Situ Plant Canopy and Potting Medium Temperatures under Two Greenhouse Temperature Regimes

McAvoy¹

1992

HortSci

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Root-zone and plant canopy temperatures were continuously monitored as a poinsettia (Euphorbia pulcherrima Willd. ex JSI.) crop was grown in the greenhouse under warm day/cool night [(+) DT-NT] or cool day/warm night [(-) DT-NT] temperature regimes. Day temperatures were imposed from 0900 to 1700 hr. Light levels photosynthetic photon flux (PPF) and outside ambient air temperatures were also monitored. Temperature differences between the root-zone and plant canopy microenvironments were most extreme during the night-to-day and day-to-night temperature transition periods. The temperature difference between the plant canopy and the root zone following temperature transition periods had been previously identified as a critical factor affecting stem elongation. Overall poinsettia height was consistently shorter under the (-) DT-NT than under the (+) DT-NT environment.

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Plant response and energy savings for bench-top-heated greenhouses

Sachs

Sisto

Jenkins

et al. 1992

Scientia Horticulturae

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The Effect of Elevated Root Zone Temperatures of Various Duration on Growth and Development of Several Poinsettia Cultivars

Cited by 4 publications

References 0 publications

Bench-top Root-zone Heating Hastens Development of Petunia under a Lower Air Temperature

Bench-top Root-zone Heating Hastens Development of Petunia under a Lower Air Temperature

In Situ Plant Canopy and Potting Medium Temperatures under Two Greenhouse Temperature Regimes

Plant response and energy savings for bench-top-heated greenhouses

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