The Growth and Development of Montane Species at Near‐Freezing Temperatures

Abstract

Studies were conducted to determine species response to low—temperature environments. Apical development was found to progress at near—freezing temperatures throughout the winter except when the plants were encased in a solid soil—ice matrix. Claytonia lanceolata and Nemophila breviflora shoots developed above the soil surface, under snow cover. In both species, chlorophyll content was inversely proportional to depth of snow cover. Spectrophotometric analysis of light penetration through snow indicated about 10% penetration through shallow layers (ca. 3.5 cm), and 0.01% through layers of 69 cm. C. lanceolata, Orogenia linearifolia, and Erythronium grandiflorum plants developed complete floral structures during the winter months, these being protected by leaves or an apical sheath (Orogenia).

Ecophysiology of a snow-bed bryophyte Kiaeria starkei during snowmelt and uptake of nitrate from meltwater

“…The low light penetration through the snowpack (maximum 13% at 10 cm depth) recorded in this study is similar to that of studies completed in North America (e.g., Kimball et al 1973;Tieszen 1974) but is a factor of 10 lower than that in an antarctic study (Walton 1982). The absolute quantity of light penetrating the snow in the current study does not vary with light intensity at the surface.…”

“…Other workers showed snow cover to have an insulating effect, resulting in subnivean temperatures remaining constantly at O°C, even when the ambient temperature was below freezing (Kimball et al 1973;Scott and Larson 1985;Salisbury 1985) and even when snow cover was only 25 cm deep (Kimball et al 1973). No ambient temperatures of below 0°C were recorded during this investigation to enable the effects of this on the subnivean temperatures to be elucidated.…”

The Effect of Long Exposure to Low Temperatures on the Cold Hardiness of Sprouting Wheat in the Dark

“…When field-grown material was transferred to an illuminated growth cabinet at 3'C after the end of December, it lost hardiness much faster than material that was left in the field (Roberts 1919\. Long-term storage at -10'C of the sprouting hardened seeds caused damage to the seedlings. A similar but less pronounced trend was observed at -J.5"C (Table 1) If the cover rises to 50 cm, the light falls to about 0.04Vo of full daylight and is relatively deficient in both the red and blue ends of the spectrum which are required for photosynthesis (Kimball et al 1973 (Roberts 1979 (Sakai 1956;Salt 1961;Rammelt 1972;Pomeroy et al 1975;Gusta and Fowler r9t1). …”

“…Thus, flats of plants hardened for several weeks could not be stacked in a cold room after growth at 3"C without damaging the plants or using spacers which would necessitate the use of more space than was available. Plants in the field under snow cover are exposed to low light intensities (Kimball et al 1973). Seeds sorouted in the dark for no more than 7 wk at 0.5 to t.0'C produce seedlings small enough that flats of them can be stacked since emergence usually occurred between '7 and 9 wk after moistening depending on whether the temperature was at the low or high end of the specified range (0.5'C-1.0"C).…”

Low Temperature Photosynthesis in Successional Winter Annuals

“…Competition among species can be reduced by some plants growing when other plants are dormant. Kimball et al (1973) show that ability of some montane herbs to grow and develop at nearfreezing temperatures in early spring reduced competition from larger species developing later in the season.…”