To solve this problem, we need to analyze each statement about sapwood and heartwood:$\newline \bullet$Option 1: Sapwood is involved in conduction of water and minerals from root to leaf.$\newline$ - Sapwood, also known as alburnum, is the outer part of the secondary xylem.$\newline$ - It is active in the conduction of water and minerals.$\newline$ - Therefore, this statement is correct.$\newline \bullet$Option 2: Sapwood is the innermost secondary xylem and is lighter in colour.$\newline$ - Sapwood is actually the outermost part of the secondary xylem, not the innermost.$\newline$ - It is lighter in color compared to heartwood.$\newline$ - Therefore, this statement is incorrect.$\newline \bullet$Option 3: Due to deposition of tannins, resins, oils etc., heart wood is dark in colour.$\newline$ - Heartwood, also known as duramen, is the central, non-living part of the tree.$\newline$ - It becomes dark due to the deposition of substances like tannins, resins, and oils.$\newline$ - Therefore, this statement is correct.$\newline \bullet$Option 4: Heart wood does not conduct water but gives mechanical support.$\newline$ - Heartwood is non-functional in terms of water conduction.$\newline$ - It provides structural support to the tree.$\newline$ - Therefore, this statement is correct.$\newline$Based on the analysis, the incorrect statement is Option 2.