Pollen tube the pollen tube responds to extracellular guidance signals to achieve fertilization. Pollen tubes are produced by the male gametophytes of seed plants. They act as conduits to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms. Pollen tubes were first discovered by Giovanni Battista Amici. Pollen tube formation is important for sexual reproduction to occur in seed plants. Plants have separate structures such as microsporocytes and megasporocytes and the pollen grains are transported to the female gametophyte
Resistant starch manufactured foods. Starches with high amylose content generally have increased resistant starch. Resistant starch (RS) is any starch or starch digestion products that are not digested and absorbed in the stomach or small intestine and pass on to the large intestine. RS has been categorized into four types: Processing may affect the natural resistant starch content of foods. In general, processes that break down structural barriers to digestion reduce resistant starch content, with greater reductions resulting from processing. Whole grain wheat may contain as high as 14% resistant starch, while milled wheat flour may contain only 2%. Resistant starch content