Julius von Sachs

Today is the birthday of the German botanist known as the Father of Plant Physiology, Julius von Sachs, who was born on this day in 1832.  

In the 1860s, Sachs tested adding a variety of nutrients to plants growing in water. He was trying to determine what plants need to live. It was early, early efforts on modern-day hydroponics.
In 1864, Sachs determined that blue light is the most important color for inducing phototropism in plants. Plants are generally blind to other colors; which is why you don't see plants bending toward the lamps inside your house; unless you are using grow-lights!
In 1868, Sachs became Head of the botanical institute at Würzburg University.  Sachs was a good friend of Frank Darwin. When Darwin needed a lab to conduct his experiments on plants growing toward the light, he naturally used the world-class lab of his friend, Julius von Sachs, at Würzburg U.
Sachs himself was studying how plants process light. He correctly identified that starch was a product of the sunlight process known as photosynthesis. He proved that chlorophyll in the chloroplast is involved in photosynthesis. Sachs is responsible for identifying structures like the organelle and chloroplasts. 
Sachs used some ingenuity to help him come up with things like planter boxes with one glass side so that he could better understand the formation of roots. Using a magnifying glass, he could discern the development of root hairs and cellular protrusions.