首页   按字顺浏览 期刊浏览 卷期浏览 The effect of a diurnal period of supra-optimal temperature on the seed vigour of sunfl...
The effect of a diurnal period of supra-optimal temperature on the seed vigour of sunflower

 

作者: A.A. Nel,  

 

期刊: South African Journal of Plant and Soil  (Taylor Available online 1998)
卷期: Volume 15, issue 1  

页码: 19-21

 

ISSN:0257-1862

 

年代: 1998

 

DOI:10.1080/02571862.1998.10635109

 

出版商: Taylor & Francis Group

 

关键词: Emergence;seed vigour;soil temperature;sunflower.

 

数据来源: Taylor

 

摘要:

The daily maximum temperature in the upper 20 mm of sandy soils is often higher than 45°C on cloudless days during November, December and January in the summer rainfall region of South Africa. At these supra-optimal temperatures, sunflower seedling vigour declines, resulting in a low plant population and lack of uniformity of plant density. The aim of this experiment was to quantify the effect of peak daily temperatures on the emergence of sunflower in a controlled environment. A3×4×5×3 factorial design with three cultivars, four growth chamber temperature treatments of 40, 45, 50 and 55°C, applied daily for periods of 3, 4, 5, 6 and 7 hours and three replicates of 20 seeds, were used. Seeds were planted to a depth of 25 mm in sand moistened to field capacity and incubated at 30°C. Treatments commenced after 24 hours. Emerged seedlings were counted daily. An emergence index, which takes both the rate and homogeneity of emergence into account, was calculated. Cultivars differed in their heat tolerance. This may be due to genotype or seed quality differences. The index declined rapidly above a threshold temperature of ca. 44°C. Some seedlings survived and emerged at temperatures above 50°C.

 

点击下载:  PDF (187KB)



返 回