アカマツとクロマツのスミワケに関する研究(2) : アカマツ・クロマツ針葉の耐乾性について

This paper treats of the drought resistance of needles of Pinus densiflora and P. Thunbergii, and is a part of the writer's research on their habitat seregation.
To find their differences in the resistance to severe drought, needles were dried in desiccators in which <Na>_2S0_4 was placed at 30℃.
The results obtained are as follows :
1) The drying speed of needles of P. densiflora is faster than that of P. Thunbergii and the ratio is 5 : 3.
2) New needles dry faster than old.
3) When their needles lose water above a certain limit, they can not recover their nor mal water content.
4) Needles of P. densiflora reach this limit at double the speed of P. Thunbergii.
5) From these results, it may be concluded that P. Thunbergii is more adaptable to severe drought than P. densiflora.