Cucurbit Genetics Cooperative Report 18:21-22 (article 10) 1995
Jianhui Liu and Hongwen Cui
Department of Horticulture, Northwestern Agricultural University, Yangling, Shaanxi 712100, P.R. China
Chilling injury can occur during cucumber production (2). The most feasible method of increasing the chilling resistance of crop plants is by genetic manipulation. Breeding for chilling resistance requires a method for evaluating chilling sensitivity. Results with cucumber fruit (3, 4) and plants leaves in other species suggest that ethylene measurement (increase) after chilling could provide a means by which genotypes could be rated for chilling resistance. However, the effect of chilling on ethylene release in cucumber (seedling) has not been reported. The objective of this research was to study the relationship of ethylene release in cucumber seedlings after chilling and define a method for evaluating chilling resistance.
Methods. Chilling sensitive and tolerant cucumber cultivars [Heidanb-1 (tolerant), Nongda-11 (tolerant), Jin-7 (sensitive), Xiong-58 (sensitive)] were grown in a growth chamber under a 12-h photoperiod (photon irradiance of 30000 lux) with mean day and night temperatures of 25 and 18C, respectively. The age of seedlings when chilling temperatures were applied was 12 days from seeding. The seedlings of each cultivar were divided into four lots, and assigned as either control (20C) or one of three chilling treatments (3.0 and -3C) cultivars were then incubated for 6, 18 or 36 h.
After the chilling exposure, the seedlings were transferred to a 20C room and held for 4 h. Then, about 3 g of cotyledonary tissue from plants in each treatment was sealed in 75 ml jars for 1 h. Subsequently, 1 ml samples were taken from each jar and ethylene were measured by gas chromatography.
Results and Discussion. Chilling injury varied with chilling temperature. The degrees of chilling injury could be reflected by rate of electrolytic leakage. The rate of electrolytic leakage increased by chilling stress (Table 1). Difference in chilling cultivar sensitivity were defined by rate of electrolytic leakage after chilling at -3C (18 h). ‘Heidan-1’ and ‘Nongda-11’ were tolerant to chilling, while ‘Jin-7’ and ‘Xinong-58’ were sensitive to chilling.
Table 2 shows that ethylene production of seedlings varied with chilling temperature. Ethylene evolution remained very low in seedlings exposed to 20C, and less ethylene was produced after chilling at 3C. Ethylene production increased rapidly, however, when seedlings were chilled at 0C, and decreased significantly with chilling at -3C when compared to ethylene production at 0C. This result agrees with previous studies.
After the transfer of cucumber seedlings from 0 to 20C for 4 h, ethylene production increased rapidly, and there were significant cultivar differences. Higher ethylene levels for extended periods were found in chilling tolerant cultivars when compared to sensitive cultivars (Table 3). This result indicates that ethylene production after chilling at 0C positively correlates (associates) with chilling resistance in cucumber cultivars. Moreover, these results suggest that ethylene production after re-warming of chilled seedlings could serve as a good indicator of chilling sensitivity.
Table 1. Effect of chilling temperature on the rate of electrolyte leakage in cotyledons of four cucumber (Cucumis sativus L.) cultivars at 4 h after seedlings were transfered to 20C (%).
Cultivarz |
20C |
3C |
0C |
-3C |
| Heiden-1 (tolerant) | 10.8 | 12.5 | 32.3 | 70.5 |
| Nongda-11 (tolerant) | 10.9 | 12.8 | 33.4 | 73.9 |
| Jin-7 (sensitive) | 10.4 | 14.1 | 35.9 | 92.7 |
| Xinong-58 (sensitive) | 11.4 | 12.8 | 38.2 | 94.4 |
zSeedlings were chilled for 18 h before transferring.
Table 2. Effect of chilling temperature on ethylene production of four cucumber (Cucumis sativus L.) cultivars at 4 h after seedlings were transferred to 20C ( μ g.g-1 .h-1 ).
Cultivarz |
20C |
3C |
0C |
-3C |
| Heidan-1 (tolerant) | 0.2707 | 0.449 | 0.889 | 0.493 |
| Nongda-11 (tolerant) | 0.2510 | 0.451 | 0.778 | 0.464 |
| Jin-7 (sensitive) | 0.2674 | 0.344 | 0.619 | 0.392 |
| Xinong-58 (sensitive) | 0.2331 | 0.401 | 0.557 | 0.398 |
z Seedlings were chilled for 18 h before transferring.
Table 3. Changes of ethylene production of four cucumber (Cucumis sativus L.) cultivars with chilling periods at 0C after seedling transferred to 20C for 4 h (μ g.g-1 .h-1).
Cultivar |
6 h |
18 h |
36 h |
| Heiden-1 (tolerant) | 0.609 a | 0.889 Aa | 1.276 Aa |
| Nongda-11 (tolerant) | 0.479 a | 0.778 AaB | 0.921 Abb |
| Jin-7 (sensitive) | 0.383 a | 0.619 Bb | 0.678 Bc |
| Xinong-58 (sensitive | 0.401 a | 0.557 Bb | 0.538 Bc |
Literature Cited
- Chen, Y.Z., and B.D. Patterson. 1985. Ethylene and 1-amino-cyclopropane-1-carboxylic acid as indicators of chilling sensitivity in various plant species. Aust. J. Plant Physiol. 12L377-385.
- Liu, H.X., S.X. Zeng, and Y.R. Wang. 1985. Effect of low temperature on SOD activity in various organs of different chilling-sensitive cucumber seedling. Acta Phytophysiologica Sinica 11(1):48-57.
- Wang, C.Y. and D.O. Adams, 1980. Ethylene production by chilled cucumbers. Plant Physiol. 66:841-843.
- Wang, C.Y. and D.O. Adams. 1982. Chilling-induced ethylene production in cucumbers. Plant Physiol. 69:424-427.