Types of Sap:
– Xylem sap consists of hormones, mineral elements, and nutrients.
– Transport in xylem moves from roots to leaves.
– Xylem sap transport may be disrupted by cavitation.
– Cavitation can be caused by water stress or freeze-thaw cycles.
– Phloem sap contains sugars, hormones, and minerals in water.
Xylem Sap:
– Movement is explained by the cohesion-tension theory.
– Other theories include osmotic pressure gradients and axial potential gradients.
– Cavitation disrupts xylem transport.
– Environmental stresses like water stress and freeze-thaw cycles impact xylem transport.
– Xylem sap transport moves from roots to leaves.
Phloem Sap:
– Phloem sap flows from sugar source to sugar sinks.
– Loading and unloading patterns are determined by conductivity and plasmodesmata.
– Mobile proteins and RNA play a role in long-distance signaling.
– Some insects feed directly on phloem sap.
– Phloem sap is consumed by a limited range of animals due to its extreme nature.
Human Uses:
– Maple syrup is made from sugar maple xylem sap.
– Birch juice is harvested for human consumption in some countries.
– Palm tree sap can be used to make palm syrup.
– Specific palm trees are used for making syrup in different regions.
– Human consumption of sap is common in various cultures.
References:
– How to Remove Tree Sap From a Car.
– General Introduction to the Mineral Nutrition of Plants.
– Driving forces for water lifting in the xylem conduit.
– Cohesion-tension theory of sap ascent.
– Xylem Embolism in different tree types.
Sap is a fluid transported in xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant.
Sap is distinct from latex, resin, or cell sap; it is a separate substance, separately produced, and with different components and functions.
Insect honeydew is called sap, particularly when it falls from trees, but is only the remains of eaten sap and other plant parts.