Steady state transcript levels of psbA, rbcL, atpB, and psbN genes accumulated differentially in mature leaves of a field-grown tree Populus deltoides during natural diurnal cycle and in dark adaptation followed by irradiation. The rbcL transcript accumulated independent of irradiation under diurnal conditions, which demonstrated a correlation with the phenomenon of midday depression in photosynthesis. The psbA and atpB transcripts accumulated more in dark whereas psbN accumulated more in light. Diurnal rhythm of gene expression in mature chloroplasts was independent of development related changes. and S. Srivastava, P. K. Trivedi, P. Nath.
At first glance, tensegrity structures give the impression of levitation, but, of course, they do not deny gravity. They are a beautiful example of the application of basic physical laws and applying physical principles in practice. The term tensegrity refers to structures formed by rigid bodies under pressure in a network formed by mechanical tension.