Effects of water availability and temperature increase on pollen grains of Bromeliaceae from São Paulo Metropolitan Region Green Belt biosphere reserve

Abstract

With the trend in the last decades of temperature increase and longer periods of drought in the São Paulo Metropolitan Region Green Belt Biosphere Reserve, a study on the impact of those stressor agents on native plants of RBCV-SP and on those ones maintained in situ and ex situ has become necessary. A successful pollination process, with viable pollen grains, is an essential factor for maintenance of native plants. Among the stressor agents, the water availability and increase of temperature have been considered important factors that affect the reproductive period of plants. The effects those factors have been observed in species of Bromeliaceae that are considered indicators of environmental changes. The objective of this study is to perform a classical palynological evaluation that covers pollen morphology using technological tools such as light microscopy and scanning electron microscopy to verify possible abnormalities in the pollen grains of native species of Tillandsia L. and Vriesea Lindl. of RBCV-SP due to its exposure to the factors associated with climate changes that have occurred during the last decades. Further will be evaluated the effects of water suspension and increase of temperature on pollen productivity and viability in plants of the Nidularium minutum Mez through simulations of expected future situation due to climate changes. For this will be made floral induction experiments with the use of Ethephon. This species is endemic of Paranapiacaba mountain range and plants that were reserved to controlled experiments have been kept in a greenhouse of the Botanical Institute of São Paulo, State Park Parque Estadual das Fontes do Ipiranga. The data will be compared to pollen grains of plants maintained under conditions representing the situation before the climatic changes that have been predicted for the end of the 21st century. (AU)