To assess the floral life-times, individual flowers (N = 30 in the
dry and N = 45 in the rainy season) were observed from opening to
senescence. Another 353 flowers (N = 152 in the dry and N = 201 in
the rainy season) were used for the following measurements: calyx
length, greatest corolla diameter and the total length of the corolla
tube, largest stamens, and the pistil size. Further, the length of one
anther and of the style branches of each flower was measured and
the number of ovules counted. Measured parameters of the mor-
phological characters were correlated with rainfall, temperature
and photoperiod data.
The number of pollen grains of one anther per bud in pre-
anthesis was counted (N = 25 buds in the dry and N = 25 in the rainy
season) and grain viability was tested with acetic carmine (Dafni
et al., 2005). Stigma receptivity was tested with 2% hydrogen perox-
ide (Dafni et al., 2005) in pre-anthesis (N = 55 in the dry and N = 40
in the rainy season) and open flowers (N = 55 in the dry and N = 40
in the rainy season).
The location of the floral nectary and its functionality were
analyzed in pre-anthesis and open flowers in both seasons. For
this purpose, flowers were fixed, paraffin-embedded and sec-
tioned (Johansen, 1940). The PAS test (Schiff reaction: O’Brien and
McCully, 1981) was performed to assess the presence of polysac-
charides, and additional tests were conducted for the presence of
glucose using glucose strips® (Alamar Tecno Científica Ltd.).