Life Processes ...

Plants produce a number of waste products during their life processes. As compared to animals, plants produce waste products very slowly and in very small amounts. The plants have no special organs for waste removal like the animals.
The plants remove their waste products by different methods. The main waste products by plants are carbon dioxide, water, vapor and oxygen. Carbon dioxide and water vapor are produced as wastes during respiration by plants whereas oxygen is produced as waste during photosynthesis. The gaseous wastes of respiration and photosynthesis in plants (carbon dioxide, water vapor and oxygen) are removed through the 'stomata' in leaves and 'lenticles' in stems and released to the air. The plants excrete carbon dioxide produced as a waste during respiration only at night time. This is because all the carbon dioxide produced during respiration in daytime is used up by the plant itself in photosynthesis. The plants excrete oxygen as waste only during the daytime (because oxygen is produced by photosynthesis only during the daytime when there is sunlight). Water vapor produced as a waste by respiration is, however, excreted by plants all the time (day as well as night). This waste water is excreted out by transpiration.
           The plants also store some of the waste products in their body parts. For example, some of the waste products collect in the leaves, bark and ripe fruits fall off from a tree, thus the waste products contained in them are excreted. Some of the plant waste gets stored in the fruits of the plant in the form of solid bodies called raphides. These wastes are removed when the fruit gets detached from the plant. For example, the fruit called 'yam' (zamikand) has needle-shaped raphides on its surface. The plants secrete their wastes in the form of gum and resins from their stems and branches. The plants also excrete some waste substances into the soil around them.