Abstract:

The purpose of this paper is to clarify the photosynthetic characteristics of purple cabbage, and the differences compared with cabbage. The pigment contents and photosynthetic characteristics of purple cabbage varieties 'Zaohong' and 'Hongri' were investigated by Unispec spectrometer and Ciras-2 photosystems respectively, and compared with a common cabbage variety 'Zhonggan 11'. The result showed that the two varieties of purple cabbage differ less in pigment content and photosynthetic rate (Pn), their chlorophyll content were higher, the Pn were lower than those of 'Zhonggan 11'. There were more proportion of anthocyanin in purple cabbage, but no in cabbage. The Pn of purple cabbage was highest in initial heading stage, and decreased by a less margin in last stage compared with that of cabbage. The chlorophyll content was highest in middle heading stage, but the anthocyanin content increased as growing period getting along. The daily Pn varied in a single peak curve. The light compensation point and light saturation point of 'Zaohong' was 68.5 μmo1·m^-2·s^-1, and 1,077.5 μmo1·m^-2·s^-1 respectively, the CO2 compensation point and saturation point was 70.4 μmo1·mol^-1 and 1,140 μmo1·mol^-1, which higher than those of 'Zhonggan 11'. The Pn of 'Zaohong' was highest in 20 ℃, the compensation point was －4.4 ℃ at low temperature and 51.3 ℃ at high temperature, which lower than those of 'Zhonggan 11'.

Key words: purple cabbage, cabbage, photosynthetic characteristics, temperature compensation points