Drought or Mechanical Stress Affects Broccoli Transplant Growth and Establishment but Not Yield

Abstract

<jats:p>Broccoli <jats:italic>(Brassica oleracea</jats:italic> L. Group <jats:italic>Italica</jats:italic> <jats:sc>cv</jats:sc>. Green Duke) seedlings were subjected to brushing with a piece of cardboard (40 strokes/min, 1 min twice daily), wind (7 m·s<jats:sup>-1</jats:sup> for 5 min twice daily) or drought (visible wilt for 2 hours daily) treatments. Plant response to treatment was affected by seasonal or environmental conditions. All conditioning treatments reduced leaf dry weight and area, stem dry weight and length, and the total shoot and root dry weights in an experiment conducted in Sept. 1986 (Fall 1986). However, in experiments conducted the following year, broccoli transplants treated in March (Spring 1987) showed little response to the treatments, while transplants treated in August (Fall 1987) showed only a moderate response. In Fall 1986 and 1987, brushing improved field establishment as measured by the rate of shoot dry weight gain over the period of field establishment. Yield of the primary head of broccoli transplants treated in either Spring or Fall 1987 was not affected by the conditioning treatments. Brushing may provide an effective alternative to drought or plant growth retardants in conditioning broccoli transplants prior to field planting.</jats:p>

Brushing effects on the growth and mechanical properties ofCorispermum mongolicumvary with water regime

“…No physical damage occurred to the plants. This type of brushing was chosen because it can simulate the mechanical effects of wind on plants without affecting their microclimate (Biddington & Dearman 1985;Latimer 1990). Plants were supplied with 200 or 400 ml water per day for the low and high water treatments respectively.…”

“…Generally, high water availability results in increased allocation to shoots at the expense of roots, and plants will also tend to be taller. Evidently these responses are in the opposite direction to thigmomorphogenesis (Grace et al 1982;Latimer 1990;Ennos 1997;Anten et al 2005). In many arid ecosystems, such as the Mu Us Sandland in China, plants tend to be exposed to high levels of MP because wind speeds tend to be high and vegetation is sparse, so plants do not shield each other from wind (Wang et al 2008).…”

Mechanical Conditioning for Control of Growth and Quality of Vegetable Transplants

“…However, Piszczek and Jerzy (1987) found that stem elongation of tomato transplants was reduced more effectively by small doses (5 sec) of shaking stress applied frequently (six times daily) than by a larger dose applied once daily (60 sec) or once every 3rd day (90 sec). Research on mechanical conditioning of vegetable transplants has typically used a minimum of 1.5 min of brushing applied once (Biddington and Dearman, 1985a) or twice (Latimer, 1990;Latimer et al, 1991) daily.…”

Responses of Aster, Dusty Miller, and Petunia Seedlings to Daily Exposure to Mechanical Stress

“…Using MS to control elongation of vegetable seedlings has been studied widely, and MS applied by brushing is recommended for conditioning cauliflower and broccoli (Brassica oleracea L. var. Botrytis Group) seedlings (Biddington and Dearman, 1985;Latimer, 1990). To our knowledge, studies on the responses of bedding plant seedlings to MS are not reported in the literature.…”

“…The response to MS may depend on several factors, including MS method (Beyl and Mitchell, 1983;Pöntinen and Voipio, 1992), season (Beyl and Mitchell, 1977;Wurr et al, 1986), and environmental conditions (i.e., Latimer, 1990). Furthermore, species differ in Received for publication 3 Jan. 1994.…”