During photosynthesis, the last reactant is called light energy. The plant absorbs this energy through its green pigments, called chlorophyll. So Li Ming is correct.
Reactants are substances that are used in a chemical reaction, and undergoes a chemical change to transform into a product. A chloroplast is an organelle found in the leaves or green cells of the plant tissues. It exhibit pigment named as chlorophyll which captures the sunlight required for photosynthesis. Neither chloroplast nor chlorophyll are reactants of the process of photosynthesis, but the light energy captured through them is used for the process of photosynthesis. The carbon dioxide from the atmosphere and water already present in plant are the reactants of photosynthesis and they produce product (carbohydrates) in the presence of light energy from sun.
Therefore, Julian is correct for disagreeing the fact that chlorophyll is a reactant of photosynthesis.