Temperature and substrate on Plukenetia volubilis L. seed germination

The objective of this work was to evaluate the effect of temperature and substrate on the germination of P. volubilis seeds. Seeds harvested from 25 matrix plants were submitted, in two studies, to conditions of (i) sowing in rolled paper towel at the temperatures of 10, 15, 20, 25, 30, 35, 40, and 45 degrees C, for the evaluation of germination, first count of germination, germination speed index and mean time for germination, and (ii) sowing in the substrates paper towel, sand, Bioplant (R), Bioplant (R) and micron, superfine, fine, medium and coarse vermiculite. The same evaluations mentioned in the first study were conducted at the temperature of 30 degrees C, as well as plant growth. The treatment replicates were distributed in a completely randomized block design and the effects of temperature were compared by polynomial regression analysis. The substrates were compared by the Scott-Knott test at 0.05 probability level. The data show that the ideal range of temperature for the germination of P. volubilis is between 25 and 30 degrees C. The temperature of 20 degrees C is the minimum for germination and those above 35 degrees C are lethal to these seeds. The most favorable substrate for P. volubilis seed germination is micron or fine vermiculite.