Tại sao lá vàng trong mùa thu?
ác phân tử tạo màu vàng và cam chính là nguyên nhân khiến cây thay áo khi thu sang, nhưng điều gì khiến nhiều loại cây đỏ rực rỡ vẫn còn là bí ẩn. Màu lá còn tiết lộ cho ta biết mức độ stress của cây. Lá cây phản ứng trước sự giảm nhiệt độ và ánh mặt trời yếu và ít hơn của mùa thu bằng cách ngừng sản xuất diệp lục - chất tạo điều kiện cho cây bắt ánh sáng và tạo ra năng lượng. Bởi diệp lục rất nhạy cảm với điều kiện lạnh, nên trong những trường hợp như sương đến sớm, lá cây sẽ đổi màu rất nhanh.
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