Studies were undertaken to elucidate the moisture relationships in germinating sugarcane setts* and the precise role of moisture in the early stages of germination.
It was found that when the controlling effect of the apical meristem was removed by cutting the cane into individual, single-budded setts, the water in the cane moved into the bud. It appeared that the meristemic cells of the bud (and root primordia) must attain a certain critical water content before they can start to sprout.
Increasing the water content of setts increased the moisture in the bud and root primordia until they attained the critical level, when sprouting was hastened. Bud and root primordia appeared to compete for water in the sett. Removal of buds hastened the sprouting of root primordia. When the water content of setts was increased the inhibiting influence of buds on the sprouting of root primordia was nullified.
At 96% relative humidity both buds and root primordia sprouted and grew out, but at 85% relative humidity, buds sprouted but root primordia did not. This disparity in the sprouting condition of buds and root primordia appeared to be due to the protective action of the bud-scales. When the water content of the setts was increased both the buds and root primordia sprouted, but the latter dried up shortly thereafter.
Experiments showed that the water in a sett was adequate for the germination of its buds and that, in the early stages, the role of soil water was only indirect.