The experiment was carried out to determine the varietal difference in morphological and physiological characters during early growth period of indica varietes, in the Department Agriculture, Peradeniya, Ceylon in 1963.
Results obtained are summarized as follows:
1. There was remarkable difference among varieties on the elongation of plumule in dark at room temperture. The varietal difference of the growth speed during early stage was closely related to that of fertilizer response, also the elongation of radicle on the local varieties in dry zone gave relatively long elongation as compared to the others.
2. When deep sawing, the indica varieties was observed development of crown roots from mesocotyle node with elongation of mesocotyle, and some varieties was shown the develoment of the mesocotyler roots.
3. The responses to gibberellin applied to the seeds, giving shoot elongation, shown remakable difference among the varieties. Namely, some varieties gave high sensitivity, while some varieties gave very low responses.4. A negative correlation was found between the resistance of seedlings against flooding of indica varieties and the elongation of shoot during flooding.

View full abstract

The seeds as well as germinating seeds of varieties of Japonica and Indica type, each 7 in number, were treated for certain hours with the solution of KClO₃, followed by washing with water and being allowed to grow on seed beds and, after several days when young seedlings attained 2-3cm in height, the toxicant resistance was determined by testing the symptoms of injury on both their leaves and rootlets.
According to the results obtained, it was shown that Japonica varietyes were generally more resistant than Indica ones to the toxicant resistance between rice varieties of above-noted two different type.
Based upon the hypothesis ever proposed by Yamasaki, one of the authors, the toxicant resistance of plants to the chlorate depends on their quantity of reducing matters which convert the chemical into hypochlorite (KClO), much poisonous to plants.
Accordingly, the results obtained, it is supposed, will afford certain suggestions for further comparative physiological studies on Japonica versus Indica type of paddy rice.

View full abstract

[in Japanese]

View full abstract