Hill Reaction
THE HILL REACTION: EFFECT OF HERBICIDES (CLEAROUT 41 PLUS AND DIURON 50 WP) IN CORN (ZEA MAYS) LEAVES
JENNY A. ADTOON
ELIEZER B. GALOPE II
SANDY FAYE D. SALMASAN
JYAN DESSE M. SOLANO
MARIANNE KRISTELLE E. YARRA
INTRODUCTION
Photosynthesis sustains almost all of the living world directly or indirectly. It is the process of converting light energy to chemical energy of sugars and other organic compounds. The process depends on the interaction between two sets of reactions, namely the light-dependent and light-independent reactions.
The light-dependent reactions convert low energy electrons from splitting of water to a high energy state in the form of NADPH. This process is also coupled with ATP synthesis. The photosynthetic electron transport occurs in thylakoid membranes inside chloroplasts.
It was first demonstrated by Robert Hill that photosynthesis could be “uncoupled” if the thylakoid membranes and the stroma components of chloroplast are separated via cell fractionation. The Hill reaction is also referred to as photolysis of water with the subsequent evolution of oxygen. Isolated thylakoids do not contain much of their complement of electron acceptors hence a lot of artificial electron acceptors are used to study the Hill reaction in vitro (the final electron acceptor in vivo is NADP). Many of these artificial electron acceptors accept electrons at different sites along the transport pathway. This study used DPIP dye as an artificial electron acceptor in determining the effects of two herbicides on photosynthetic electron transport by isolated thylakoids of Zea mays leaves. DPIP in analysed by color changes it exhibits – it is blue in its oxidized form and turns colorless when reduced.
The shikimate pathway is a biosynthetic sequence in plants to produce the aromatic amino acids phenylalanine, tyrosine, and tryptophan. One of the enzymes of the pathway, EPSP (5-enolpyruvylshikimate-3-phosphate) synthase, is often targeted by
JENNY A. ADTOON
ELIEZER B. GALOPE II
SANDY FAYE D. SALMASAN
JYAN DESSE M. SOLANO
MARIANNE KRISTELLE E. YARRA
INTRODUCTION
Photosynthesis sustains almost all of the living world directly or indirectly. It is the process of converting light energy to chemical energy of sugars and other organic compounds. The process depends on the interaction between two sets of reactions, namely the light-dependent and light-independent reactions.
The light-dependent reactions convert low energy electrons from splitting of water to a high energy state in the form of NADPH. This process is also coupled with ATP synthesis. The photosynthetic electron transport occurs in thylakoid membranes inside chloroplasts.
It was first demonstrated by Robert Hill that photosynthesis could be “uncoupled” if the thylakoid membranes and the stroma components of chloroplast are separated via cell fractionation. The Hill reaction is also referred to as photolysis of water with the subsequent evolution of oxygen. Isolated thylakoids do not contain much of their complement of electron acceptors hence a lot of artificial electron acceptors are used to study the Hill reaction in vitro (the final electron acceptor in vivo is NADP). Many of these artificial electron acceptors accept electrons at different sites along the transport pathway. This study used DPIP dye as an artificial electron acceptor in determining the effects of two herbicides on photosynthetic electron transport by isolated thylakoids of Zea mays leaves. DPIP in analysed by color changes it exhibits – it is blue in its oxidized form and turns colorless when reduced.
The shikimate pathway is a biosynthetic sequence in plants to produce the aromatic amino acids phenylalanine, tyrosine, and tryptophan. One of the enzymes of the pathway, EPSP (5-enolpyruvylshikimate-3-phosphate) synthase, is often targeted by
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