A late spring in Europe and the adaptability of plants. Epigenetic regulation seems to play a major role in plants' ability to adapt to and remember unusual climate patterns.

After an unusually long winter in Europe and a very cold and wet spring that lasted until late May, many perennial plants have come late into leaf and flower. As such, 2013 will probably see a late harvest and possibly reduced yields, despite the hot weather that came later in July. This response by plants to a long cold period is a normal adaptation to adverse weather conditions, but this unusual period of weather has given biologists a chance to understand how plants determine the optimal time for essential processes such as flowering or fruit ripening in response to current and even past climate conditions. Such knowledge could be applied to agriculture both to deal with adverse weather and to breed plant vari eties better adapted to harsher climates, especially in colder regions. Plants use various environmental cues to determine their flowering time in the spring. Some species respond directly to temperature changes whereas others use day length, which results in less variation in the timing of their leaf and flower development between successive springs. Some observers, however, have noticed that some plants seem to respond not just to the immediate season but also to the previous one: during a cold spring they will still come into leaf and bud at the normal time if the previous spring was warmer than usual. This suggests that plants are not just subject to the whims of the weather, but that they are capable of adapting to long-term environmental conditions by taking two or more years of weather patterns into account. Such observations are informing the search for the molecular mechanisms and genes involved in these adaptations, with the hope of developing plant varieties that have a high tolerance for a range of stress factors, including drought, parasites and cold. There is also the potential to alter the time at which plants come into flower and fruits ripen, which would have great commercial advantage for farmers.