Seasonal changes of dry matter productivity and photosynthesis in Gerbera hybrida.

This study was conducted to study the seasonal changes of dry matter productivity and photosynthesis ability of Gerbera hybrida cv. Cosmo in greenhouse cultivation. For growth analysis, dry weight and leaf area were measured every month during growing period (Apr. 2006~Mar. 2007). Photosynthesis rates in accordance with light intensity, CO and leaf characteristics were measured by LI-6400 and seasonal changes were also checked. The maximum RGR (relative growth rate) and NAR (net assimilation rate) were observed at early growth stage. Among the growth analysis characters, NAR of individual plant and LAI (leaf area index) of canopy were the main factors in plant productivity and it could be assumed that CGR (crop growth rate) was the maximum at 3.42 g.m.day when LAI was 2.09. Light saturation and compensation points were 804 and 32 mol.m.s, respectively. Intercellular CO concentration and photosynthesis were positively correlated and regressed as binomial. Maximum photosynthesis rate would be achieved at 784 mol.mol of intercellular CO concentration. Photosynthesis rates were increased until 4 months after transplanting and then decreased during winter season. Leaf area/leaf dry weight ratio and vapor pressure deficit in leaf were positively correlated with photosynthesis.