Plant Structures 1 Flashcards
area between cell walls called
Middle Lamella
What is Middle Lamela filled with?
living or non living?
Pectin
non living
Cell wall is made up of ________ cells bounded to __________
plasmalemma(plasma membrane)
Why is middle lamella important for fruit ripening
pectases secreted into middle lamella and break down pectin causing softening
What forms a continuum throughout the plant?
how is this possible?
The plasma membrane
possible because of the plasmodemata(pores) occuring through cell walls allowing cytoplasm to flow through
Continuum of living material is called the _______, which flows through the _________
symplast
cytoplasm
Apoplast, and 2 examples
Non living plant tissue,
middle lamella and dead xylem
the 3 components of the plasmalemma
and their functions
lipids (40%) arranged in bilayer- polar out nonpolar in (makes up unit membrane)
proteins (40%) most are enzymes that transport metabolites accross membrane, some extend through, while some are inside or outside
carbohydrates(20%) linked to proteins and lipids
what is the lipid component in the plasmalemma made up of?
phospholipids, glycolipids, and sterols
why is membrane structure important
linked to resistance to chilling in many crops
symptoms of chilling injury
-surface pitting
-sunken watersoaked areas
-abnormal pigmentation
-inability to ripen
-increased susceptibility to pathogens
Membrane at non chilling temperature
-LIQUID CRYSTALLINE STATE
-protines move in phospholipid matrix
-increased functionality of enzymes. these are responsible for transport in & out of cell
-semi permeable
Membrane at chilling temperatatures
-SOLID GEL PHASE
-membrane activity to standstill
-increased permeability–> cracks, leakage
- accumulation of toxins
-alteration of enzyme activities
Fully saturated vs not fully saturated fatty acid tails and chilling injury
saturated tails pack closely–> Gel quickly
unsaturated tails dont pack as quickly
Chilling injury is much lower where
there is a higher proportion of unsaturated fatty acids
