Answer: I'm curious, how are you planning to apply the nitrogen to the leaves? Nitrogen occurs naturally in many forms, and an interesting thing about this element is that it changes its form readily...combining with other elements and molecules to form other molecules.<br><br>You probably know that a large percentage (about 78 percent by volume) of the atmosphere--the air we breathe--is made up of nitrogen. Certain microbes are capable of taking this nitrogen and "fixing" it into ions which are thenavailable for plants to use as nutrients. (This is a complex and very interesting subject that I won't go into here...I love chemistry!)<br><br>So, plant leaves are exposed to atmospheric nitrogen all the time. Other forms of nitrogen include the ammonium ion (NH4-); this is the form found in many fertilizers like ammonium nitrate. This ion also readily converts to ammonia gas (NH3), which in some cases can be absorbed by plant leaves. <br><br>Some people apply "foliar" fertilizers containingnitrogen to plant leaves. (This is done by dissolving fertilizer in water and spraying on the leaves). This is sometimes done if the plant is under stress and isn't able to absorb nitrogen through its roots quickly enough. So applying nitrogen fertilizer (in liquid form) to a plant's leaves should result in that plant taking in some of that nitrogen. <br><br>The common result of nitrogen application is a surge of vegetative growth, and a "greening up" of the leaves. Nitrogen applied in too concentrated a solution to the soil around a plant can "burn" plant roots; its seems likely that a concentrated solution may also injure plant leaves.<br><br>I hope this is helpful! It makes me want to get out my old soil chemistry textbook!
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