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Dr. Hongqi Li - Biography
My research interests include:
Paleobotanic Research Interests
My research interests are mainly focused on the "origin of angiosperms" that has been an "abominable mystery" since Darwin. Currently, we still do not know when, where, and from which plants the flowering plants originated, while the confirmed, earliest angiosperm megafossils are 125 million years old, found from the Yixian Formation, Lower Cretaceous, Liaoning, northeastern China.
I have published three papers on three different fossil flowering plants found from the Yixian Formation, including Archaefructus eoflora (Ji et al., 2004), Archaeamphora longicervia (Li, 2005) and Hyrcantha decussata (Dlicher et al., 2007). Considering that angiosperms had highly diversified during the Early Cretaceous, the origin of angiosperms must be much earlier.
To trace the possible PreCretaceous angiosperms, I am applying two approaches, studying the plant morphology and anatomy and analyzing fossil molecules from 1) angiosperms collected form the Yixian Formation of the Early Cretaceous, northeastern China; 2) possible angiosperm fossil plants collected form the Middle-Late Jurassic, northeastern China; 3) fossil plants that have some angiosperm characteristics, collected form the Late Triassic- Early Jurassic, northern and southern China; and 4) Permian gigantopterids (250-290 million years ago) from China and USA.
I have been studying Chinese gigantopterids since 1983 and found their morphology (e.g., broad leaves, complex reticulate venation) and anatomy (e.g., paracytic stomata, vessels. 1996 Science) make them resemble angiosperms the most among all living and fossil seed plants, and their Permian age well matches the origin time of angiosperms suggested by molecular clock studies (see my gigantopterid-related-papers published in 1990, 1994, 1996, 1998, and 1999). However, because the confirmed earliest angiosperms are only about 125 million years old, I have been hesitating to further correlate gigantopterids with angiosperms, unless I obtain some more convincing evidence.
Because there is no DNA or RNA preserved in PreCretaceous fossil plants, we have to use other stable fossil molecules to trace lineage of angiosperms. Oleanane appears to be an ideal angiosperm biomarker because it has been found in most angiosperm families, and its increase matches well with the diversification of flowering plants during Cretaceous.
From the Yixian Formation, I have reported a species flowering plant, Archaefructus eoflora (Ji et al., 2004). More excitingly, I also have found fossil pitcher plants from the same place in the same fossil flora (Li, 2005). The fossil pitcher plants of Archaeamphora longicervia share many characteristics with modern sarraceniacean pitcher plants of America. Since Sarraceniaceae are placed within the crown group of angiosperms, the discovery of the sarraceniacean-like fossil pitcher plants suggests the basal angiosperms should have originated much earlier, possibly as 280 million years ago as recent molecular clock studies suggested. I have found oleanane from the Chinese gigantopterids of Permian (Taylor et al., 2006, Paleobiology 32(2): 179-190). Nature editor Dr. Henry Gee pointed out that, "If they (gigantopterids) are found to be closer to the flowering plants, the lineage leading to flowering plants will be put securely back into the Permian period" (http://www.nature.com/nsu/991209/991209-8.html).
Carnivous Plants Research Interests
The Archaeamphora longicervia found from the Lower Cretaceous is actually a fossil pitcher plant that shares many morphological and anatomical characteristics with modern sarraceniacean pitcher plants of America (Li, 2005). This conclusion is also supported with the discovery of angiosperm biomark molecule oleanane from Archaeamphora specimens. Since Sarraceniaceae are placed within the crown group of angiosperms, this is the earliest fossil record of carnivorous plants and the earliest fossil record of crown group of angiosperms.
My discovery of fossil pitcher plant Archaeamphora also inspired my interests in study of modern carnivorous plants, including their origin, phytogeography, morphology, ecology, conservation, and molecular as well as medicinal studies. I had one graduate student conpleted his master degree research on a comprehensive investigation of local populations of Sarracenia purpurea. Beside these, I have organized the 6th Conference of International Carnivorous Plant Society, hosted at Frostburg State University, June 1-5, 2006.
When I was working on modern pitcher plants and trying to find out some special molecules that could be used as specific biomarkers, I found many of them yield mocule plumbagin that have studied as a potential anticancer agent. That lead me to further expanded my research into examine plumbagin and other molules, with a new technology, T-Hertz Spectrascopy, and ended with several publications.
Therefore, I study not only fossil plants, but also modern plants. In particular, when I cannot find some morphology/anatomy of a modern plant from literature, I will dissect the plant and use my own observation to clarify some characteristics in related fossil plants. For example, when I study the earliest, anatomically preserved fossil cycad, I dissected living cycad material to obtain a comprehensive understanding of anatomy of cycads. These studies may lead to important discoveries to clarify some evolutionary problems.