Phloem Anatomy, Exudation, and Transport of Organic Nutrients in Cucurbits

Translocation of Photosynthetically Assimilated C14 in Straight-Necked Squash

“…A mercury column (10) allows for volume expansion when CO2 is pumped in at the feeding port (11). B) Top side view, showing diameter of the air leads (1), the CO2 feeding port (2), the outlet to Hg column (3), the modeling-clay seal around the petiole (4) and the distribution of the leaf blade (5) French (4). The sugars were identified against known standards.…”

Metabolic networks of Cucurbita maxima phloem

“…There is a massive flux of assimilates exported from leaves to sink organs in cucurbits, resulting in a net increase in dry weight of fruits from 0.1-2 g/h and phloem velocities of about 60-240 cm/h (Schaffer et al, 1996;Crafts, 1932). Therefore, a huge gradient in osmotic pressure must be present.…”

“…The vascular system of plants and, specifically, of cucurbits is long known not to be a uniform string of companion cell/sieve element complexes (Kempers et al, 1998) (CC/SE) but spatially distinguishable into external, internal (Golecki et al, 1999), and extrafascicular phloem veins (Crafts, 1932). Therefore, cuts or incisions might cause a mixture of the contents of all these veins, thereby losing spatial resolution.…”

Seasonal Study of Tissue Function and Organic Solute Movement in the Sunflower

“…The colloid content of the phloem cells is very high, much higher than in other plant tissues, which indicates that the movement of organic solutes may be due to certain colloidal responses. He suggests that the organic solutes may move along colloidal surfaces, since CRAFTS (16) has shown that it is probable that protoplasmic strands are continuous throughout the plant. STEWARD (39) suggests that energy from living protoplasm assists in the movement of organic solutes, a suggestion which HOAGLAND (25) originally made for the inorganic solutes.…”