Measurement of Seed Responses to Environment

A. M. Wilson
1972 Journal of range management  
Highlight The objective of this work was to develop a method for evaluating seed responses to field environments. Seeds placed in soil in the field were brought into the laboratory for germination tests under controlled conditions. Hastening of germinat,ion, an indicator of seed responses to environment, was determined by subtracting the number of days required for samples placed in soils in the field to reach 50% germination from the days required for air-dry control samples to reach 50%
more » ... to reach 50% germination. A temperature of 5 C provided a more sensitive test for measuring hastening of germination than 10 or 20 C. Measurements of environment and of seed responses to environment will help explain why seeds sometimes fail to germinate on harsh rangeland sites. Environmental conditions during the interval from planting to germination may be critical in the establishment of perennial grasses on harsh rangeland sites. Yet, we know little concerning responses of seeds to extreme and fluctuating temperature and moisture conditions during this period. We lack this type of information because suitable methods for measuring these responses have not been available. This paper describes a method for measuring hastening of germination and discusses how it may be used in evaluating responses of seeds to environment. The method is adapted from the work of Keller and Bleak (1968). The concept of hastening of germination suggests that planted seeds do not remain quiescent until the time germination can be observed. Instead, it suggests that during periods of favorable environment they carry on numerous biochemical reactions which eventually lead to cell division, cell enlargement, and the protrusion of root and shoot. Thus, hastening of germination is an integrated measure of how far seeds have progressed toward germination. Materials and Methods Seeds of Nordan crested wheatgrass (Agropyron desertorum (Fisch. ex Link) Schult.) were treated with 20 mg of thiram (tetramethylthiuram disulfide) per g dry weight to inhibit microbiological growth. In a laboratory test, samples of 100 seeds were placed on two layers of moist seed-germinating blotter paper in petri dishes and incubated at 5, 10, or 20 C in a germinator. The l Cooperative investigations
doi:10.2307/3897016 fatcat:cr3ro656ynhldcrt3umvngjesm