In a saucepan, bring the stock to a boil; keep warm over low heat. Heat the olive oil in a large heavy saucepan. Add the artichokes, carrots, onion, celery and leek and cook over moderate heat for 5 minutes. Add the zucchini and cook, stirring occasionally, until the vegetables are crisp-tender, about 5 minutes longer. Add the rice and stir over moderate heat until translucent, 2 to 3 minutes. Add the wine and cook over moderately high heat, stirring, until absorbed. Add 1 cup of the stock and cook, stirring, until absorbed. Continue adding the stock, 1 cup at a time, stirring constantly until it is absorbed before adding more. The rice is done when it's tender and creamy but still firm to the bite, 20 to 25 minutes.