The Denoted: The literal (intended / preferred ) message is that on a culturally-signified day ("Mothers Day") you should treat your mother as if she were a queen - the monarch of your family group - and the most satisfying way to do this is to purchase and consume something. Note: deliberate double (polysemic) meaning of word "treat".
The Connoted: The use of cucumber slices points to a series of floating signified: the colour green is shorthand for Green (in the ethically political / cultural senses of the word); it also signifies Nature and the 'naturally-occuring' (items that seemingly oppose the synthetic, the artificial (note how the 'real' '3D' cucumber slices sit on top of the 'false' '2D' image of the queen; how they also imply lenses through which the world can be seen in new / fresh ways)); images that connote the 'natural' often have a 'naturalising' intent: they make an artificial message seem natural, for it to be part of the natural world, the "order of things". Cucumber slices also imply the phrase "cool as a..." with all its additional inferences of 'coolness', 'freshness', a soothing, relaxing balm, as well as a luxuriant beautifying process, something normally found only in an expensive clinic or spa. A 'treat.' The hand placing the cucumber is your hand; you are the child - the 'daughter': for is it not a woman's hand we see? - perhaps you are a mother yourself; in which case you will understand, by inference, the 'duties' required of a mother, both upwards and downwards through the generations of your family and culture. It is your mother's turn to be served, rather than providing service (as it will one day be your's). The queen - often pictured / depicted in the media as unsmiling - smiles here, showing her pleasure at the idea of you purchasing something, as your own mother will almost certainly smile and look upon you with favour upon receiving her gift or service. We are all customers - the givers and recipients of various transactional physical and emotional services within our families. Our familial relationships are themselves an economy.
The Mythic / Ideological: That a queen - a monarch - rules over a culture, leads it; and that it is the duty of those outside the so-called 'royal' family to serve and provide for those inside her class and position without question. It is part of the 'natural order of things' within our culture - a given. That this ideology underpins everything is reflected by the 'flatness' of the image of the Queen, that it sits behind or under the artificially '3D' images of the cucumber (the natural world) and the hand (you) highlights this. An image of the national flag then sits behind the Queen - another layer, one representing the wider 'culture' of which the Queen, its notional head, rules over through various institutions. The royal family refer to their own lives as "service", a "responsibility", that it is their "duty" to serve the nation - they hint they they are perhaps burdened by this duty, that it is of a higher order than the duties (labour) that fall upon the rest of society. "It is 'hard' being a member of the ruling class." This is how they deflect accusations of privilege while reinforcing their entitlement, and this model of privilege-deflection is reflected / echoed 'down' through the layers and strata of our culture. But - wait! - the sub-image of the flag sits at a jaunty, euphoric angle - it implies fun, euphoric consumption - and is tinted pink to attract the gaze of the female consumer, as our culture has designated pink to be the primary signifying colour of femininity. It remains similarly unchallenged - a mythic 'fact' - that the woman should be the prime supplier of services within the family - the colour-scheme, the length of the fingernails, various elements within the advert all conspire to reinforce this 'truth'. She (The Queen) is the queen of all women within your culture, but today she is having fun. "Now, serve your own mother for one day as you serve me on all other days."