低温与脱锻炼处理下2种绣线菊膜脂肪酸变化研究

试验应用气相色谱技术,以抗寒能力不同的园林树木华北和金山绣线菊为材料,通过低温与脱锻炼处理,研究低温诱导时其膜脂肪酸种类与含量的变化,探讨绣线菊细胞膜膜脂肪酸变化与抗寒能力的关系。结果表明:华北和金山绣线菊膜脂肪酸主要由豆蔻酸(14∶0)、棕榈酸(16∶0)、油酸(18∶1)、亚油酸(18∶2)、亚麻酸(18∶3)等组成,约占膜脂总脂肪酸的90%以上;饱和膜脂肪酸以棕榈酸(16∶0)为主,不饱和膜脂肪酸以亚油酸(18∶2)和亚麻酸(18∶3)为主;低温处理下金山绣线菊不饱和膜脂肪酸含量变化显著,华北绣线菊不饱和膜脂肪酸含量变化不显著,其较高的抗寒能力可能与低温下较稳定的膜脂不饱和度(IUFA)水平有关,维持华北绣线菊较稳定的膜脂不饱和度水平,需要一定的低温水平;低温处理对华北和金山绣线菊饱和膜脂肪酸含量也有一定影响。     

Photosynthetic Acclimation to Cold as a Potential Physiological Marker of Winter Barley Freezing Tolerance Assessed under Variable Winter Environment

Winter‐hardiness is a complex trait limiting cultivation of winter barley (Hordeum vulgare ssp. vulgare) with respect to the regions of temperate climate. In the present studies, we verified whether inexpensive and fast physiological markers characterizing photosynthetic acclimation to cold may provide robust characteristics of winter barley genotypes for improved frost resistance. Freezing tolerance of 28 winter barley varieties and advanced breeding lines were tested for three winters in field‐laboratory experiment and under fully controlled conditions. To increase the environmental variability of freezing tolerance, a part of the plants were also de‐acclimated under semi‐controlled conditions and re‐acclimated in laboratory before freezing tests. After controlled cold acclimation, apparent quantum yield of photosystem II (F_v/F_m) as well as photochemical (q_P) and non‐photochemical (NPQ) coefficients of chlorophyll fluorescence quenching were studied. Field‐laboratory method assessment of freezing tolerance gives distinct and even opposite results in subsequent years. Also de‐acclimation interacted with growth conditions in the field, giving different rankings of genotypes each year. The results obtained suggest that high level of freezing tolerance measured in laboratory, which is connected with photosynthetic acclimation to cold may be not sufficient for the expression of field resistance, especially when winter conditions are not favourable for cold acclimation.