With the imbibition of water, the h

With the imbibition of water, the hormone signal in barley, gibberellic acid (GA), is carried from the embryo to the aleurone layer of the endosperm. The GA activates the DNA for the gene encoding alpha-amylase in the aleurone cells. Transcription and translation of that gene results in the production of alpha-amylase inside the aleurone cells. This enzyme is shipped by ER into the Golgi, sorted and packaged into vesicles, and exported through the cell membrane by exocytosis. The amylase is thus dumped into the endosperm area. There the amylase breaks down starch into the sugar maltose which is transported to the embryo. The sugar fuels respiration in the embryo so it can grow. The radicle protrudes from the seed coat, and germination is accomplished. After plant physiologists figured this out, we could easily tell the brewing industry how to produce more beer per bushel of barley. What was the answer?
A similar mechanism exists in lettuce (lettuce has no aleurone and the embryo is a dicot), but the activating chemical is a pigment called phytochrome. This chemical exists in two different forms: Pr and Pfr. Pfr is the form of phytochrome that photoactivates the genes for amylase in lettuce; Pr is inactive. Whether a lettuce seed germinates depends on how much of each of these two forms of phytochrome is present in each cell. Typical lettuce seed batches germinate at 30-60% if placed in darkness because at least this percentage of seeds have enough Pfr to stimulate germination. If, however, you put the lettuce seeds in red light (660 nm), the red light causes all the Pr to change into Pfr. Now 85-95% of the seeds can sprout because they all have an abundance of Pfr inside. On the other hand, if you put lettuce seeds in far-red (730 nm) light, the far-red light causes all the Pfr to change into Pr. In far-red light, then, all the seeds have essentially no Pfr and so very few (0-5%) actually sprout. After plant physiologists explained this, Burpee Seed company understood why customers have trouble getting lettuce seeds to germinate well in their gardens...they tend to "bury" the seeds...they need to be exposed on the surface!

ผลลัพธ์ (อังกฤษ) 2:

With the imbibition of water, the hormone signal in barley, gibberellic acid (GA), is carried from the embryo to the aleurone layer of the endosperm. The GA activates the DNA for the gene encoding alpha-amylase in the aleurone cells. Transcription and translation of that gene results in the production of alpha-amylase inside the aleurone cells. This enzyme is shipped by ER into the Golgi, sorted and packaged into vesicles, and exported through the cell membrane by exocytosis. The amylase is thus dumped into the endosperm area. There the amylase breaks down starch into the sugar maltose which is transported to the embryo. The sugar fuels respiration in the embryo so it can grow. The radicle protrudes from the seed coat, and germination is accomplished. After plant physiologists figured this out, we could easily tell the brewing industry how to produce more beer per bushel of barley. What was the answer?
A similar mechanism exists in Lettuce (Lettuce has no aleurone and the embryo is a Dicot), but the activating Chemical Called phytochrome is a pigment. This chemical exists in two different forms: Pr and Pfr. Pfr is the form of phytochrome that photoactivates the genes for amylase in lettuce; Pr is inactive. Whether a lettuce seed germinates depends on how much of each of these two forms of phytochrome is present in each cell. Typical lettuce seed batches germinate at 30-60% if placed in darkness because at least this percentage of seeds have enough Pfr to stimulate germination. If, however, you put the lettuce seeds in red light (660 nm), the red light causes all the Pr to change into Pfr. Now 85-95% of the seeds can sprout because they all have an abundance of Pfr inside. On the other hand, if you put lettuce seeds in far-red (730 nm) light, the far-red light causes all the Pfr to change into Pr. In far-red light, then, all the seeds have essentially no Pfr and so very few (0-5%) actually sprout. After plant physiologists explained this, Burpee Seed company understood why customers have trouble getting lettuce seeds to germinate well in their gardens ... they tend to "bury" the seeds ... they need to be exposed on the surface!