[Effects of irradiance on boron requirement of phaseolus aureus cutting for its adventitious root development]

This paper studied the boron requirement of Phaseolus aureus cutting for its adventitious root development under different photosynthetic active radiation (PAR). The results showed that exogenous boron supply was necessary for the adventitious root development of the cutting under 10 days of PAR at 50 or 100 micromol x m(-2) x s(-1), but unnecessary under 6 days of this irradiance and followed by 4 days of darkness. Exogenous boron supply was also necessary for the rooting under 6 days of PAR at 180 micromol x m(-2) x s(-1) and followed by 4 days of darkness. When the PAR at 100 micromol x m(-2) x s(-1) was employed for 10 days, the amount of soluble boron in each hypocotyl of the cutting was only half of that under 6 days of this irradiance and followed by 4 days of darkness, which might be the reason of the necessity of exogenous boron supply for the rooting under 10 days of PAR at 100 micromol x m(-2) x s(-1).