Record Details
Physical factors affecting longevity and germination of seed of Western dwarfmistletoe (Arceuthobium campylopodum Engelm. f. campylopodum)
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Physical factors affecting longevity and germination of seed of Western dwarfmistletoe (Arceuthobium campylopodum Engelm. f. campylopodum) |
| Names |
Beckman, Kent Mardsen
(creator) Roth, Lewis F. (advisor) |
| Date Issued | 1964-04-15 (iso8601) |
| Note | Graduation date: 1964 |
| Abstract | Longevity and germination of seed of western dwarfmistletoe (Arceuthobium campylopodum Engelm. f. campylopodum) of ponderosa pine (Pinus ponderosa Laws.) was investigated to determine: 1) the influence of humidity and temperature on seed viability and deterioration during storage; 2) the physiology of seed dormancy; 3) the composition of seed reserve food at intervals during dormancy, and 4) the influence of temperature, moisture and light on seed germination. Standard procedures were used for chemical analyses and paper chromatography; moisture conditions during germination were controlled over gradients of sulfuric acid, while light intensities and temperatures were maintained in standard growth chambers. Seed were collected in paper bags and stored both in shelters in the field and in the laboratory refrigerator. Viability determinations were made with one percent triphenyltetrazolium chloride or three percent hydrogen peroxide whereas the criterion for seed germination was radicle emergence. Western dwarfmistletoe seed, after expulsion in the fall, remain dormant for approximately six months. Preliminary investigations suggested dormancy is regulated by a chemical inhibitor associated with the endocarp. Initial seed viability varied from one infected stand to another, whereas retention of viability was correlated with temperature. Seed stored at 1.5°C retained initial viability levels for 10 months; after 10 months seed began to significantly deteriorate. In some cases, however, viability was observed after a prolonged storage period of 48 months. Western dwarfmistletoe seed germinate over a temperature range from 1.5 to 31°C. The optimum constant temperature lies between 15 and 20°C, whereas various combinations of alternating night-day temperatures revealed a combination of 5 to 15°C to be most favorable for germination. Absorption of liquid moisture is essential for germination and germination readily occurs at reduced levels of aeralion. Germination also occurs in total darkness; however, light intensities between 200 and 1000 foot candles in conjunction with favorable temperatures significantly enhance germination. Increases in photoperiod up to 24 hours progressively increased germination percentages. Red light was slightly more effective in seed germination than far-red light. Black light (near ultraviolet) was injurious to seed when levels were greater than 120 foot candles and exposures exceeded 12 hours. Unfavorable temperatures, moisture, and light during the 30 days following seed discharge appeared to be the most contributory factors toward low seed viability and accompanying low infection potentials. |
| Genre | Thesis/Dissertation |
| Topic | Ponderosa pine -- Diseases and pests |
| Identifier | http://hdl.handle.net/1957/48723 |
