A lecture titled “Space-The Final Frontier for Root Phototropism” was given by Dr. John Z. Kiss on Thursday, March 9^th.

            By way of introducing, the topic of Nastic movement was mentioned, which consisted some interesting characteristics of plant growth. From this, it was seen that the plants do not grow straight; instead, they bend and twist as they elongate and grow. This movement indicated that the plants directly respond to the external stimulus, in which Dr. Kiss introduced thigmotropism, (response to touch,) phototropism (response to light) and gravitropism (response to gravity.) The interactions of different tropisms demonstrated that different plants’ parts respond to each type of tropism differently. In stem, there is positive phototropism but a negative gravitropism, while one the other hand, roots showed the exact opposite reaction. It was also highlighted that there are different light perceptions (receptors,) that consist red, blue and white lights. Using the Arabidopsis seedlings, the effect of such lights were shown, demonstrating their effect on the plant. The experiment using white light showed that when the light was shined, the leaves started to grow towards the light while the roots faced away from the light. With red light, there was positive phototropism; however, when blue light was shined, the experiment resulted in a negative phototropism. This indicated that the response of the plant to blue light is stronger than that of the red response, thus underlining that gravitation response is stronger than photo-response in the roots. Still, Dr. Kiss mentioned that the sensing of light occurs in root itself and it is not depended on shoot-derived signals, explaining that signaling by red light is active in roots as well as the regulation of several genes in roots. It was very interesting to find out that the growth of plant involved such features, and moreover, it was also very interesting to find out that in order to study photoresponses further it can be done in space where there is absence of gravity. It was amusing to find out that NASA is also involved in the project, and I thought it would be very exciting to find out the outcome of the project as working with them sounded very thrilling…!