Hi

Pores are always there on  leaves be it dry or green i.e alive.

Pores present on leaves are used by plants for the exchange of gases and for the process of transpiration through which they loss water.

So in normal condition condition, plants lose water through the pores present on the leaves but when plant doesn't get enough water leaves dry , but it doesn't mean that pores have got destroyed, it's been seen that many leaves are when put in water, they absorb water  and again start appearing green, which suggest the presence of pores in dry leaves .


Thankyou

Yes pores are present on upper surface of leaves and are called stomata. Below is given a detailed knowledge about stomata that you should know.

Stomata consist of a pair of guard cells and open in response to the blue light present in sunlight. Opening of stomata leads to carbon dioxide uptake, explaining why photosynthesis occurs during the day. When plants are under dark conditions and/or drought stress, a plant hormone, abscisic acid (ABA) is biosynthesized and induces stomata closure. Stomata are closed during the night to prevent water loss from the plant.

When the guard cells in the stomata detect blue light, the photoreceptor, phototropin is activated and induces signaling within the cell. As a result of the signaling, the enzyme, plasma membrane proton pump (PM H+-ATPase) is activated, leading to the uptake of potassium ions. This triggers water uptake and cell swelling that opens the stomata. Although activation of PM H+-ATPase is known to be significant for stomatal opening, the full mechanism of stomatal opening is yet to be clarified.