Parenchyma - connected by plasmodesmata to sieve-tube...

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Parenchyma, fibers thin walled, living parenchyma and elongate, dead fibers are accessory storage site in xylem throughout the plant parenchyma: storage, repair; fibers: strength and non- conducting support Phloem Sieve-tube elements elongated; primary wall only; sieve areas on end walls called a sieve plate; living at maturity but lack a nucleus in phloem throughout the plant; elements lined up end to end form a sieve tube conducts dissolved carbohydrates and other foods in ngiosperms Companion cells living with variable, usually elongated shape; primary wall only;
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Unformatted text preview: connected by plasmodesmata to sieve-tube elements in phloem throughout the plant; derived from same mother cell as sieve-tube element apparently sends ATP and signal substances to the enucleate sieve-tube elements thus controlling cellular metabolism of the sieve tube elements in angiosperms Sieve cell elongated and tapering, living at maturity; primary cell wall with sieve areas; lacks a nucleus; cytoplasmn with much tubular endoplasmic reticulum in phloem throughout the plant conducts dissolved carbohydrates and other foods in gymnosperms...
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