Stratification of Seed of Pinus Strobiformis

It was not necessary to pretreat seed of Pinus strobiformis Engelm. from northern Arizona and northern New Mexico in order to increase germination values. In general, sulfuric acid treatments were detrimental; they were especially harmful when combined with stratification in moist sand. Stratification alone for 45 days produced high germination values, but these were not significantly different from those obtained from untreated seed. The numerous techniques used to hasten and produce uniform. seed germination have been adequately described and summarized (3,4). The present test is related to the part of the "Woody-Plant Seed Manual" (6, p. 272), which reads "Germination [of seeds of Pinus flexilis var. reflexa] only fair without pretreatment." However, a footnote on the same page reads "Treatment only suggested for this species; experimental data not complete." In the present note, evidence shows that scarification, stratification, and other techniques were not required for rapid and uniform germination. As part of a nursery test within a rangewide progeny study of the Pinus flexilis complex, several seed stratification techniques were used to determine the efficacy of pregermination treatments to induce more rapid and uniform germination rates. The series of tests described under the methods section was applied to the seeds of two stand collections of the southern member of the complex, Pinus strobiformis, which is nomenclaturally synonymous with P. flexilis var. reflexa Engelm.

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Author(s): John William Andresen

Publication: Tree Planters' Notes - Issue 72 (1965)