Plant development depends largely on the light it receives. In this sense, the so-called photoperiod refers to the influence exerted by periods of light and darkness on plants over a period of time, whether it is a day, a season or a solar cycle.
Each plant species needs a specific photoperiod
The organic functions of vegetables are activated or deactivated according to the number of hours of light they are exposed. There are trees that need many hours of light a day for their metabolism to work properly. In this way, if they do not receive a sufficient light impact, their growth will change (during autumn there are fewer hours of daylight and tree growth stops significantly).
Long, short and neutral day plants
Seed germination and flowering are states that occur at a specific time of year. The environmental stimulus used by plants to detect each time of the year is the basic principle of the photoperiod.
Long-day plants only flower if the light periods are prolonged. This situation occurs in the northern hemisphere in late spring and early summer, while in the southern hemisphere the situation is reversed. Some examples of modality are clover, spinach, lettuce, wheat and beetroot.
Short-day plants need more hours of darkness than light. The cane sugar , corn and tobacco are some examples of this type.
The day and night cycles of the photoperiod are not decisive for all plants, as some of them regulate their functions autonomously. Photoperiod insensitivity is present in tomatoes or cucumbers.
The photoperiod and the internal clock of plants
All living things have a biological clock that allows them to regulate their functions. In this sense, photoperiod sensitivity occurs through the interaction of two elements: sunlight received by the photoreceptors of specialized cells and the circadian clock of plants.
The link between the biological clock of plants and their adaptation to changes in light is an issue directly related to the production of agricultural crops. Plant physiology experts say that plants’ circadian clocks work flexibly, to the point of adapting to unpredictable changes in light. Knowledge of its internal mechanisms can be of great use in coping with periods of drought or in improving crop quality .