Combined effect of green-colored covers and shading on the growth of sisal (Furcraea hexapetala) plants

Plants have the ability to respond in different ways to the quality of light, its intensity, and the combination of both. In addition, chlorophyll absorbs light in the blue and red bands of the spectrum, but green and infrared light are poorly absorbed or not absorbed, yet they affect plant morphogenesis. An experiment was carried out in Tunja, Colombia, in which the influence of shading on sisal plants (Furcraea hexapetala) was evaluated. The plants were placed under green polypropylene filters that induced 55.4, 85.8 and 90.1% light reduction and were compared with open exposure plants in a greenhouse. As a consequence of shading, the values of the following variables were reduced: chlorophyll content index by between 52.2 and 55.0%, dry mass by between 80.8 and 94.0%, water uptake by between 40.9 and 44.9%, water use efficiency by between 23.0 and 53.7% and relative growth rate by between 35.1 and 58.4%, as compared to the control, while the values for the root to shoot ratio, specific leaf area and leaf area ratio were increased by ranges of 24.2 to 73.5%, 107.5 to 132.4% and 116.6 to 174.9%, respectively. The shading with green filters induced a reduction in the red/far red ratio of light. Based on these results, it was possible to infer that the sisal plants presented low plasticity for tolerating the abiotic stress induced by green-filter shading.