The promotive role of stigmasterol under salinized soil level is well documented in this report to elucidate the physiological effect of stigmasterol (10-6 and 10-4 M) to overcome soil salinity (0.59, 0.67 and 0.96m mos) on growth aspects, yield, photosynthetic pigments and sugar contents in sugar beet organs (Beta vulgaris, L.) variety Rass poly. Stigmasterol was added during vegetative and root growth stages.
Growth measurements of sugar beet plant organs as top (leaf area, fresh and dry weights) and root (diameter and fresh weight) significantly reduced with increasing salinity levels of soil, while, root length was insignificantly increased during root growth and sugar accumulation stages.
Stigmasterol significantly increased top and root measurements of sugar beet plant specially 10-6 M at root growth and 10-4 M at sugar accumulation stages except leaf area and top fresh weight at sugar accumulation stage that were significantly reduced. These concentrations gave the same trend with salinity levels specially 0.69 m mos at root growth and 0.96 mmos.
Salinity levels with or without stigmasterol significantly increased chlorophyll (a and b) contents with increasing both, while carotene content with salinity levels or its interaction with stigmasterol was insignificantly increased, however it significantly increased with stigma sterol application alone. Leaves soluble sugar were significantly increased by salinity or stigmasterol compared with control at root growth stage and insignificantly at sugar accumulation stage, also with interaction especially with (10-6 M) of stigmasterol. Salinity levels insignificantly decreased nonsoluble sugar at both stages. However, it significantly increased with stigmasterol concentrations during both stages with salinity levels. So, total sugar content of leaves was significantly increased at root growth stage and reduced at sugar accumulation stage with salinity levels. While, stigmasterol or its interaction with salinity significantly increased it at all stages compared with control.
Increasing salinity levels increased sugar contents of root compared with control at both stages, sucrose and glucose at sugar accumulation stage were significantly increased. Stigmasterol had the same trend of salinity but there was significant effect on total sugars, sucrose, glucose and TSS at sugar accumulation stage. However, sucrose and glucose were significantly increased with increasing salinity levels with stigmasterol concentrations (10-4 and 10-6 M).
Stigmasterol concentration (10-4 M) was more effective to overcome salinity effect and increase sucrose content of sugar beet root.