Perception of light and shade by some weeds

摘要

In the present study the distribution pattern of weeds with respect to their sunlight requirement is studied. For the study, five sites on the campus of University of Pune, Pune were selected and the vegetation growing beneath and outside the tree canopy was studied. The light intensity was recorded using Lux meter and with the help of random quadrats, frequency, abundance and density of these species was recorded. In addition, soil moisture and soil depth was also taken into consideration.The observations revealed that the species like Synedrella nodiflora L grows under shade only and its density gradually reduces with increase'in light intensity.The Achymnthus aspera Linn, and Lagasca mollis Cav. was recorded at the peripheral region of tree canopy under shade. Interestingly, Cassia uniflora Mill, grows only under open sunlight intensity and never found grown under shade. On some sites under open sunlight where the moisture regimes are less along with less soil depth, instead of Cassia uniflora Mill. Poaceae members were found growing,Thus with respect to above species it is concluded that the species have different levels of light perception that determines their distribution pattern and density under natural growth.