GERMINATION OF THE RED SPRUCE

Abstract

Picea rubra seed were capable of germinating promptly following maturity under a wide range of conditions. In the field, germination and survival were best on mineral soil and were favored by surface soil moisture. In the exps. the seed did not retain its vitality long when stored in the duff. Most of it germinated during the 1st season but some remained viable for 1 yr. and some for 2 yrs. The germinative energy of freshly harvested seed was 66-87% in 30 days, with an av. of 77%. During air-tight dry storage it decreased about 10% per yr. for the 1st 3 yrs. Germination of air-dry seed took place between 15[degree] and 32[degree] C, and was incomplete below 20[degree] and above 28[degree] C. The opt. range appeared to be 24[degree]-26[degree] C. After prolonged stratification at low temps., the min. temp. for germination was lowered. After-ripening at 7[degree]-10[degree] C in a moist substratum hastened germination only slightly. Light was found non-essential, but somewhat stimulating to germination. Moisture was most important, especially at the beginning of germination. Moisture absorption was rapid, and began immediately. Germination took place under water when aeration was provided. The seed tolerated a wide range of acidity, and germinated well between pH 2.0 and 7.0. Germination increased up to pH 2.0 and was poorest toward the neutral point and alkaline side. Best seedlings resulted between pH 5 and 6. The speed of germination was greater in the more acid samples. The most vigorous seedling growth was obtained in the distilled water controls, but there was no evidence that the buffered solutions used retarded germination. Molding of the seed was less severe at higher acidities.[long dash]Natural reproduction evidently depends not so much on the requirements for germination as on the factors which determine survival of the seedlings after germination.