What are the nectaries of plants for?

Although honey contains a small amount of amino acids, protein, alkaloids and other substances. It can be regarded as an aqueous solution of sugar.

Sugar is the main energy substance in nectar. The sugar concentration of nectar varies greatly between species and even within species, which mainly depends on

The concentration of plant species and environmental conditions varies from 4% to 60%, even higher in some special cases (Herreraet al.., 2006). However, the change of nectar sugar content with time is mainly influenced by the nectar secretion mode (nectar secretion rate or resorption rate) of plant nectaries (Liang Junnuo, 2007). Generally, when the sugar content of nectar is less than 8%, bees have no power to collect or collect; When the sugar content of nectar is above 8%, bees begin to collect it. If the external honey powder source is abundant, bees often wait until the sugar content reaches 15% ~ 20% before collecting it (Tan et al., 20 13).Wykes and Percival( 1952) used paper chromatography to semi-quantitatively analyze the sugar in various nectaries. They found that most nectaries are composed of glucose, fructose and sucrose, and a few nectaries also contain oligosaccharides such as stachyose and raffinose. Three common sugars in nectar

The relative content depends on the amount of sucrose hydrolyzed into glucose and fructose by sucrase in nectaries. Generally speaking, the nectar of flowers without nectar exposure, such as long tubular flowers, is usually mainly sucrose, such as clover (Trifoliumspp.) and apple (Malus pumila); But flowers with dew honey, such as cruciferous plants, often contain no sucrose, only glucose and fructose.