These changes were made to prevent depletion of nutrients in long running experiments while maintaining a low osmotic pressure. The final solution pH is 6.0, and the electroconductivity is 0.66 dS m -1 . Even though Si is not recognized as an essential mineral for plants, we include Si because Si is naturally present in the soil solution and in the plant cell wall. Arabidopsis is a facultative long-day plant and there are many interactive effects of day length, light intensity, light quality and temperature on the transition to flowering. At less than inductive photoperiods, the total photon flux determines the rate of development and time of flowering.
Higher temperatures tend to reduce the time to flowering and leaf number.
We have observed that Landsberg erecta does well at 23 C, whereas Columbia shows some signs of stress at this temperature. For plants to obtain maximal growth a balance of environmental conditions must be found that delays flowering yet produces rapid growth. We have observed that under an 8-h photoperiod plants grow large, but slowly. Whereas, under a 14-h photoperiod, plants grow more rapidly but flowering is induced early thus reducing leaf biomass. Numbers of individuals Figure 2.