This study was carried out to investigate some similarities between the nectaries of <em>Nicotiana</em> sp. and <em>Cucurbita</em> pepo, such as starch accumulation in the nectary parenchyma, changes in nectary color during maturation, and the production of a large quantity of sucrose-dominant nectar. The concentration of hydrogen peroxide in <em>C. pepo</em> floral nectar was determined in order to verify the presence of a defense mechanism similar to that found in <em>Nicotiana</em> sp. which protects nectar from yeast and bacteria proliferation. We also tested the eventual accumulation of antioxidants in the nectary of <em>C. pepo</em> as a protection against oxidative stress caused by hydrogen peroxide. The level of hydrogen peroxide found in the floral nectar of <em>C. pepo</em> was much lower than that found in <em>Nicotiana</em> sp. and the male flowers of <em>Cucurbita</em> had a higher concentration than the female flowers. The low oxidative stress induced by this level of hydrogen peroxide caused the accumulation of a low amount of lutein inside the plastoglobules which were contained in amyloplasts. Plastids of the <em>C. pepo</em> nectary are specialized in the accumulation of starch rather than antioxidants.