Effect of Low-Temperature Stress on Germination, Growth, and Phenology of Plants: A Review

Abstract

Climatic models indicated that in this century, both average temperatures and extreme events frequency will increase in the Mediterranean basin. These changes are expected to have a great impact on agriculture in general and on crop phenology in particular. Great progress has been made in understanding the responses of plants to abiotic stress. There are inherent physical, morphological, and molecular limitations to the plant’s ability to respond to stress. Plant responses to abiotic stress are dynamic and complex. Among the various abiotic stresses, low temperature adversely affects germination, normal plant growth, development, and phonological events. Consistent with the increasing temperatures, crop development is expected to be faster; thus, phenological stages will be reached early, and the length of the growth period of crops with determinate cycle (i.e., cereals, grapevine, etc.) will be shorter. These impacts, together with the higher risk to have extreme climate events during sensitive phonological phases, may have strong negative effects on final yield and on yield quality. The actual impact of phonological change needs to be assessed for specific crop environment combinations, providing the basis to formulate feasible adaptation options to climate change. In other terms, the simulated changes in phenology cannot be interpreted without considering the environmental context in which a species lives. For winter crops, the effect of predicted prolonged summer drought periods and heat weaves for the next decades may be smoothed or prevented due to the faster development that will allow escaping these and then avoiding reduction in final yields. In contrast, crops, whose growing cycle takes place in summer time, are likely to experience a severe reduction of final yield as the result of increased frequency of extreme climatic events and a reduced time for biomass accumulation to yield.