The Rice EP3 and OsFBK1 E3 ligases alter plant architecture and flower development, and affect transcript accumulation of microRNA pathway genes and their targets

Fruit yield reduction due to high temperatures has been widely observed in Solanaceous crops. Our past experiments have demonstrated that Capsicum annuum cultivars Ace and Bell Boy completely fail to produce fruit when grown at constant 33 °C. However, flowers are produced, continually. To determine which stages of flower development are sensitive to high temperatures, pepper buds, ranging in size from 1 mm to anthesis, were exposed to high temperatures for 6 hr, 48 hr, 5 days, or for the duration of the experiment. Fruit set for each bud size was determined. Exposure to high temperatures at anthesis and at the 2-mm size stage for 2 or more days significantly reduced fruit production. To determine whether inhibition of pollination, inhibition of fertilization, and/or injury to the female or male structures prevents fruit production at high temperatures, flowers from pepper cultivars Ace and Bell Boy were grown until flowers on the 8th or 9th node were 11 mm in length. Plants were divided between 25 °C and 33 °C constant growth chambers for 2 to 4 days until anthesis. At anthesis, flowers from both treatments were cross-pollinated in all combination, and crosses were equally divided between 33 or 25 °C growth chambers until fruit set or flowers abscised. All flower crosses resulted in 80% to 100% fruit set when post-pollination temperatures were 25 °C. However, post-pollination temperatures of 33 °C significantly reduced fruit production. Reduced fruit set by flowers exposed to high temperatures during anthesis and pollination is not a result of inviable pollen or ovule, but an inhibition of fertilization or initial fruit development.

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Effect of High Temperatures on the Postharvest Flowering of Specialty Floral Crop Species

HortScience ◽

10.21273/hortsci.33.3.447f ◽

1998 ◽

Vol 33 (3) ◽

pp. 447f-448

Author(s):

Millie S. Williams ◽

Terri Woods Starman ◽

James E. Faust

Keyword(s):

United States ◽

Heat Tolerance ◽

Flower Development ◽

Consumer Satisfaction ◽

The United States ◽

Plant Canopy ◽

Flower Number ◽

Flower Bud ◽

Crop Species ◽

Mature Flower

Flower growers experience decreased consumer satisfaction with plant species that cease flowering during the summer. The objective of this experiment was to characterize the heat tolerance of four specialty floral crop species in order to predict their summer performance in the different climatalogical regions of the United States. The effect of increasing temperatures on the duration of postharvest flower development was determined for Ageranthemum frutescens `Butterfly' and `Sugar Baby', Brachycome hybrid `Ultra', and Sutera cordata `Snowflake'. Plants were grown in a 18 °C greenhouse until marketable with foliage covering the container and flowers distributed evenly across the plant canopy. Plants were then placed in a phytotron to determine their heat tolerance. Temperature set points of 18, 23, 28, and 33 °C were delivered serially at 2-week intervals, starting at 18 °C. Plants were then returned to 18 °C after the 33 °C treatment. Immature flower bud, mature flower bud, flower and senesced flower numbers were collected once per week. Sutera `Snowflake', and Brachycome `Ultra' had the greatest flower number at the 23 °C temperature, decreasing in the 28 °C environment. Argeranthemum `Butterfly' and `Sugar Baby' had greatest flower number at 28 °C, but flowers were smaller and of lower quality than at 23 °C. Flower development of all cultivars ceased at 33 °C, but when plants were returned to the 18 °C production greenhouse, flower development resumed. According to normal average daily temperatures in Knoxville, Tenn., Ageranthemum frutescens `Butterfly' and `Sugar Baby' would flower until mid-June, while Brachycome hybrid `Ultra' and Sutera cordata `Snowflake' would flower until mid-May.

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