What would you expect the concentration of sugar in the stigmas of the flowers to be?
Answers
Answer:
The pistil usually is located in the center of the flower and is made up of three parts: the stigma, style, and ovary. The stigma is the sticky knob at the top of the pistil. It is attached to the long, tubelike structure called the style. The style leads to the ovary that contains the female egg cells called ovules.
Answer:
Sugary secretions are present in many plants and frequently they are linked with reproductive processes. Most of the gymnosperms, both extant and extinct, possess a pollination drop, a diluted sugary secretion protruding from the micropyle, which serves for pollen capture, hydration, and transport in the ovule. It is most probable that this secretion attracted insects giving origin to a plant–insect relationship for pollination based on a sugary solution well before the raise of angiosperm. Floral nectar, a new type of sugary exudate produced by a specific secreting tissue (the nectary), evolved rapidly when the transition from naked ovule to closed carpel was completed and the pollination drops were no longer available as a food resource for insects. Floral nectar is widely distributed and very diverse in the extant angiosperms where it represents the more common reward for a large variety of pollinators. In this chapter, we highlight the evolutionary relationship between nectar and pollination drops in terms of morphology, physiology, ecology, and biochemistry.
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