Câu 53: Câu 53: What is the “quiescent center” and where is What is the “quiescent center” and where is it located? What is known about the it located? What is known about the function of the quiescent center? function of the quiescent center? This structure is located This structure is located just behind the root cap and just behind the root cap and consists of 500-1,000 seemingly consists of 500-1,000 seemingly inactive cells. inactive cells. These cells are usually in These cells are usually in the G1 phase of the cell cycle the G1 phase of the cell cycle and divide only about once and divide only about once every 15-20 days. every 15-20 days. Quiescent and Quiescent and meristematic cells are different meristematic cells are different in sensitivity to environmental in sensitivity to environmental problems such as radiation. problems such as radiation. For example, meristematic For example, meristematic cells stop dividing when cells stop dividing when exposed to x rays while exposed to x rays while quiescent cells are unaffected by quiescent cells are unaffected by radiation and soon begin radiation and soon begin dividing to reform the dividing to reform the meristem. meristem. Cells in the quiescent Cells in the quiescent center function as a reservoir center function as a reservoir to replace damaged cells of to replace damaged cells of the meristem. the meristem. Its important because it Its important because it organizes the patterns of organizes the patterns of primary growth in roots. primary growth in roots.