Studies on the differences of physiological and ecological characteristics of the artificially raised amphidiploid in comparison with those of its parents. : XI.The germination and storage of pollen.

Abstract

(1) Studies were made on the germination and storage of the pollen of "Nori-Asa" (Abelmoschus glutino-terdilis), an amphidiploid crop raised between Abel. esculentus and Abel. Manihot, in compariscn with those of its parents. (2) The optimum amounts of agar-agar and succharose in artificial germination were 3-4% and 30-35% tespectively in " Nori-Asa ", 0.5-3%' and 5-30% in esculentus and 7% and 25% in Manihot. The germination % was ca. 90% or more in escelentus and "Nori-Asa ", but only 50-60% in Manihot, so far as the present experirnents are concerned. (3) The optimum temperature for the pollen germ;.nation was 28'-31'C in escgilentus and "Non Asa" and 25'C in Manihol. The relative humidity good for the same was 50-100% in esculentus and 75 100% m Mamhot and " Norl Asa ". The optimum pH valu of the medium for the germination was 4.0-7.0 in esculenllis and 5.6-7.0 in Manthol and "Nori-Asa". Light and darkness showed no effect on the germination of the pollen in the three crops . (4) The elongation of the pollen tube occurred most speedily and its length attained was the longest in esculentus. Manihot was rapider in the tube elongation at the early stage th.an "Nori-Asa "but the le<ngth attained was the shortest of all thle three crops. In " Nori-Asa " the tube elongated slowly at the early stage and quite rapidly later, but the length attained was intermediate of its; parents . ( 5 ) The germination % of the pollen was superior when it was gathered in the following periods : in esculenteis from 6 hours 'previous to and to 10 hours after the flower opening, in Mardhot from the fiower opening to 14 hours after it and in " Nori-Asa " from 2 hours previous to, and to 12 hours after the flower opening. ( 6 ) The best conditions of temperature and relative humidity for the storage of the; pollen were 15'C-22'C and 80% respectively in the three crops. Escelerdus showed the longest period in which the pollen vitality was kept and M22:nihot the next, "Norl Asa" being about the same as in Manthot.