Growth cabinet studies into cold-tolerance of Festuca arundinacea populations: III. Cold tolerance of roots and shoots

Abstract

Plants of three populations of Festuca arundinacea, syn. 1 and syn. 2 (North African) and S. 170 (British) were subjected to 3 h cold stress treatments in the range 13-25 °F. Such treatments were applied independently to either roots or shoots, the untreated plant portions remaining at 35-40 F°.In all populations considerable tiller death occurred following exposure of roots to temperatures of 17 °F or below; however at no temperature was there complete killing of tillers. Tiller deaths occurred following shoot exposure to temperatures below 21 °F in syn. 1 and syn. 2, and below 19 °F in S. 170. Universal mortality occurred in all populations after shoot exposure to 13 °F.

The Independent Assessment of Frost Hardiness of Excised Laminae, Excised Roots and Trimmed Tillers of Tall Fescue (Festuca arundinacea)

“…Thomas & Lazenby 1968c), it is Conductivity measurements have often been used to assess frost hardiness of plants and excised plant parts (e.g. Dexter, Tottingham & Graber 1932;Stuart 1939;Wilner 1960;Olien 1971;Ketchie, Breman & Ballard 1972;Stergios & Howell 1973).…”

“…Several studies of hardiness to frost in forage grasses have concentrated on survival of seedling or established tillers (Robson -& Jewiss 1968;Thomas & Lazenby 1968a;Lorenzetti et al 1971). Thomas & Lazenby (1968c) studied the effects of exposing different attached parts of tall fescue plants to low temperatures and suggested that cold tolerance of any part of a tiller could not be satisfactorily assessed by the subsequent survival of the whole. This paper describes the assessment of damage, caused by freezing, to excised roots and excised laminae of leaves, and the effect of freezing on the subsequent regrowth of trimmed tillers.…”

The relative hardening of roots and shoots and the influence of day‐length during hardening in perennial ryegrass

“…This was found in Poa annua submerged in an ice sheet for 60 days (Beard & Olien, 1963). Formation of adventitious roots may also explain the higher survival rate of plants of F. arundinacea when roots were exposed to low temperatures than when shoots were exposed to similar temperatures (Thomas & Lazenby, 1968).…”

“…Where these have been considered separately, difficulty has been encountered in distinguishing between the influences of low temperature on the roots per se and its effects on the crown of the plant. Thomas & Lazenby (1968) found that recovery in tall fescue (Festuca arundinacea Shreb.) was greater if the roots were subjected to low temperature than if the shoots were subjected to the same temperature.…”

Growth cabinet studies into cold-tolerance of Festuca arundinacea populations: II. Responses to pretreatment conditioning and to number and duration of low temperature periods

“…B to fall to 32 °F in less than 1 h. It may be that the latent heat of the soil water delayed further fall, for at the end of 6 h the soil temperatures had fallen only to 26-27 °F, compared with 18 °F (almost the same as the air temperature) after 12 or 18 h. Rogers (1962) has suggested that roots of tall fescue are more susceptible to low temperatures than are shoots, and this would seem a possible explanation for this apparent relationship of survival and soil temperature. Differential susceptibility of roots and shoots is examined in a later paper (Thomas & Lazenby, 1968c).…”