Table 3.
Summer frost resistance (LT ± SD, °C), temperature span between LT10 and LT90, and the range of ice nucleation temperature NT min/max and Δ min–max (in parentheses) in reproductive shoots of the investigated plant species at different stages of reproductive development (b1 before bolting; b2 bolting; a anthesis; f1 early fruit development)
| Stage | Frost resistance | Dwarf shrubs | Herbs | Cushion plants | ||||
|---|---|---|---|---|---|---|---|---|
| Loi pro | Rho ferr | Cer uni | Ran gla | Sax bry | Sax cae | Sax mos | ||
| b1 | LT 50 | ND | −5.5 ± 0.9 a,A | ND | ND | −9.3 ± 0.8 a,A | −5.3 ± 1.6 a,A | −7.9 ± 1.6 a,A |
| LT10 | ND | −4.5 ± 1.0 | ND | ND | −7.1 | −2.6 ± 1.3 | −4.3 ± 0.7 | |
| LT90 | ND | −6.5 ± 1.2 | ND | ND | −11.9 | −8.1 ± 1.9 | −11.5 ± 3.6 | |
| LT100 | ND | −7.6 | ND | ND | −12 | −11.0 | −14.2 | |
| Δ LT10–LT90 | ND | 2.3 ± 3.8 | ND | ND | 4.8 | 5.6 ± 0.6 | 7.2 ± 4.0 | |
| NT min/max (Δ) | ND | −2.9/−8.3 (5.4) | ND | ND | −3.8/−5.0 (1.2) | −2.0/−4.9 (2.9) | −2.3/−8.7 (6.4) | |
| b2 | LT 50 | −9.7 ± 1.2 b,c,B | −3.9 ± 1.7 a,A | −4.4 ± 0.4 a,A | −8.8 ± 1.9 b,A | −3.8 ± 0.8 a,B | −3.3 ± 0.8 a,B | −4.1 ± 1.9 a,B |
| LT10 | −5.8 | −3.0 ± 1.3 | −2.1 ± 0.7 | −7.2 ± 1.7 | −1.4 ± 0.8 | −2.2 ± 0.7 | −2.2 ± 1.1 | |
| LT90 | −12.4 ± 1.2 | −4.8 ± 2.7 | −6.7 ± 1.9 | −10.5 ± 1.9 | −6.1 ± 1.8 | −4.4 ± 0.8 | −5.9 ± 2.9 | |
| LT100 | −14.5 | −7.2 | −10.5 | −11.7 | −8.6 | −6.7 | −10.0 | |
| Δ LT10–LT90 | 6.6 | 1.7 ± 4.4 | 4.6 ± 1.4 | 3.2 ± 0.9 | 4.7 ± 2.2 | 2.1 ± 1.6 | 3.7 ± 2.5 | |
| NT min/max (Δ) | −3.6/−7.4 (3.8) | −3.1/−8.3 (5.2) | −2.2/−6.3 (4.1) | −3.0/−8.8 (5.8) | −3.0/−8.2 (5.2) | −2.0/−5.7 (2.7) | −1.8/−9.7 (7.9) | |
| a | LT 50 | −4.9 ± 0.3 a b,A | −5.6 ± 0.2 b,A | −4.8 ± 0.4 ab,A | −8.0 ± 1.2 c,A | −4.3 ± 0.6 a,B | −2.7 ± 0.9 a,B | −4,2 ± 0.5 a b,B |
| LT10 | −4.2 ± 0.5 | −3.7 ± 1.0 | −3.4 ± 0.9 | −6.2 ± 1.9 | −2.1 ± 0.5 | −2.0 ± 0.9 | −2.1 ± 1.0 | |
| LT90 | −5.6 ± 0.3 | −8.2 ± 1.3 | −6.2 ± 1.3 | −9.8 ± 2.3 | −6.2 ± 1.1 | −3.4 ± 1.0 | −6.7 ± 1.3 | |
| LT100 | −9.5 | −8.5 | −7.2 | −10.6 | −7.2 | −5.9 | −8.6 | |
| Δ LT10–LT90 | 1.4 ± 0.6 | 4.5 ± 2.3 | 2.8 ± 2.6 | 3.6 ± 3.7 | 3.8 ± 1.2 | 1.4 ± 2.7 | 4.9 ± 2.2 | |
| NT min/max (Δ) | −3.6/−9.2 (5.6) | −1.8/−9.2 (7.4) | −3.1/−6.6 (3.5) | −3.0/−8.5 (5.5) | −3.3/−7.5 (4.2) | −2.0/−4.9 (2.9) | −2.8/−11.0 (8.2) | |
| f1 | LT 50 | −7.1 ± 0.9 a,B | −4.0 ± 0.7 a,A | −7.8 ± 1.1 a,B | −7.6 ± 0.4 a,A | −5.1 ± 0.8 a,A | −5.5 ± 0.5 a,A | −5.9 ± 0.9 a,A |
| LT10 | −6.5 ± 2.0 | −2.0 ± 0.3 | −6.3 ± 1.4 | −5.6 ± 1.3 | −2.6 ± 1.9 | −4.2 ± 1.0 | −4.0 ± 1.6 | |
| LT90 | −7.8 ± 1.0 | −6.1 ± 1.1 | −9.1 ± 1.1 | −9.6 ± 1.4 | −7.5 ± 1.4 | −6.8 ± 0.3 | −7.8 ± 1.1 | |
| LT100 | −9.5 | −7.2 | −9.8 | −9.8 | −10.1 | −7.2 | −9.9 | |
| Δ LT10–LT90 | 1.4 ± 2.2 | 4.2 ± 0.9 | 2.8 ± 1.4 | 3.9 ± 1.0 | 4.8 ± 3.3 | 2.2 ± 0.3 | 3.8 ± 2.1 | |
| NT min/max (Δ) | −2.5/−10.4 (7.9) | −2.6/−5.4 (2.8) | −2.9/−10.1 (7.2) | −4.5/−8.3 (3.8) | −3.3/−8.0 (4.7) | −2.0/−4.6 (2.6) | −2.2/−11.6 (9.4) | |
LT-values are means of 3–6 replicates. LT50 values and statistical indication are given in bold: different small letters in a line indicate statistical difference in frost resistance among the different species, different capital letters in a column indicate statistical difference in frost resistance among different development stages within a species; italics value shows significantly different statistical groups on the basis of α = 0.05 (one-way ANOVA, Bonferroni post hoc comparison, α = 0.05)
ND not determined