Response of Tomato Plants to Stressful Temperatures

Abstract

To investigate the abscisic acid (ABA) production of tomato (Mill.) plants in response to diurnal stressful temperatures, five-week old seedlings were exposed to day/night temperatures of 10/5, 15/10, 25/15, 35/25, or 45/35 C. The daylength was 16 hours with a light intensity of approximately 400 microeinsteins per meter per second. Plant tops were sampled at 12, 24, 48, and 72 hours. Free, alkaline-hydrolyzable (conjugated), and total ABA quantities were measured using standard gas chromatographic techniques. AU temperature regimes significantly increased both free and conjugated ABA levels over concentrations in control plants (25/15 C). The highest ABA levels were observed in plants exposed to the coolest temperature of 10/5 C. Since normal water potentials were obtained in plants of al treatments, the observed ABA response was not due to temperature-induced water stress. Therefore, temperature stress, like several other environmental stresses, induces the plant to produce high levels of ABA. Because of the similar involvement of ABA in temperature-induced and other environmental stresses, ABA may be a common mediator for all plant stresses.ABA is a naturally occurring compound of major importance in regulating plant growth and development. It has been implicated in a variety of physiological processes (1,11,13,15) and is found in elevated levels under several stressful conditions (3,4,7,8,16,18,23 Samples for ABA determination were harvested at 0, 12, 24, 48, and 72 h. Zero sampling time (09:00 h) was 3 h after the lights came on; therefore, all samples, except those at 12 h, were harvested 3 h after the lights came on. The 12-h samples were taken 1 h before the end of the light period (2 1:00 h). At each harvest, three single plant replicates (exclusive of the root system) were immediately frozen on dry ice and stored in a freezer at -18 C until analyzed. A representative sample (1-3 g) of each frozen and crushed plant was weighed, homogenized in ice-cold 90% methanol (10 ml/g fresh tissue), and filtered. ABA was analyzed according to the method described by Seeley and Powell (21). The alkaline-hydrolyzable ABA (conjugated ABA) was determined by adjusting the pH of the remaining aqueous phase to 11.0 with KOH, heating it at 60 C for 45 min, and re-extracting with methylene chloride. Acidic fractions were derivatized by ethereal diazomethane. ABA was quantified with a Tracor 222 Gas Chromatograph equipped with a Ni3 electron capture detector. Column packing was 3% OV-25 on Gas Chrom Q (100 to 200 mesh support). Purified N2 at a flow rate of 80 ml/min was used as the carrier gas.

ABA Increased Soybean Yield by Enhancing Production of Carbohydrates and Their Allocation in Seed

“…Another interesting aspect to take into account is the photosynthetic capacity of the plant. It has been reported in literature that ABA stops the photosynthesis of different species under controlled conditions (Daie & Campbell, 1981;Xu et al, 1995;Gong et al, 1998;Wilkinson & Davies, 2002;Reddy et al, 2004;Liu et al, 2005); but our results showed an increase in the content of dry matter that increases in correlation with chlorophyll levels (Travaglia et al, 2009). These results are similar to those we observed during three years of essays with field-grown wheat treated with ABA; the treated plants showed higher levels of chlorophyll and maintained green leaves longer (5 to 10 days) than control plants (Travaglia et al, 2010).…”

Protein Synthesis in Bromegrass (Bromus inermis Leyss) Cultured Cells during the Induction of Frost Tolerance by Abscisic Acid or Low Temperature

“…Endogenous levels of ABA have been shown to increase during high and low temperature growth conditions (8). Following application of exogenous ABA, improved cold resistance has been observed in alfalfa seedlings (22), potatoes (5), and suspension cultures of some plant species (4,19) and callus cultures (14).…”

Wild-Type Levels of Abscisic Acid Are Not Required for Heat Shock Protein Accumulation in Tomato

“…The greatest increase in ABA concentration has been observed in response to drought stress, yet other osmotic stresses such as salinity and PEG-mediated water deficit also result in elevated levels of ABA ( 19). Temperature also has an effect on endogenous ABA levels (8). However, the effect of a rapid increase in temperature or heat shock on leaf ABA concentration has not been widely studied (13).…”