Crossposting this in support:
Endocytosis. In that, plants are capable of absorbing molecules much larger than ions. Organic compounds, amino acids, etc. Prior theories expound that turgor pressures would prevent absorption of large molecules. Research, relatively recent early 2K, suggests that may not be the case.
Protein and low inorganic nitrogen in combination supported better growth of Arabidopsis than protein or low inorganic nitrogen alone. (A ) No nitrogen added. (B ) Protein only (6 mg BSA per ml). (C ) Inorganic nitrogen only (0.04 mg NH4NO3 per ml). (D ) Protein plus inorganic nitrogen (5.4 mg BSA per ml and 0.04 mg NH4NO3 per ml). [1]
We identified two mechanisms by which Hakea and Arabidopsis access protein. First, root-derived proteases break down protein. A smaller protein (ā50 kDa) was generated in the incubation solution of Arabidopsis roots when roots were supplied with a larger protein (66 kDa), and a proteināchromophore complex was cleaved by root-derived proteases of Hakea and Arabidopsis .
The second mechanism of protein acquisition observed was the uptake of intact protein. Although the uptake of protein into roots has not been considered previously, integrated endocytotic and secretory networks have been described in tip-growing root hairs (24). It is likely that protein enters root hairs via endocytosis and that root cells subsequently catabolize the acquired protein, but other possibilities, including membrane transport, cannot be ruled out. [2]
On Xylem transport and amino acid formation [3]:
Depending on the plant species, environmental conditions, and diurnal rhythm, amino acid assimilation might occur in roots and/or leaves (Coruzzi, 2003). Amino acids that are synthesized in roots or that are taken up directly from the soil are mainly translocated in the xylem to the shoot. Since transpiration is highest in photosynthetically active leaves, a relatively high amount of root-derived amino acids is transported to leaves. Here, amino acids are imported into the mesophyll cells, such as by AtLHT1 (Hirner et al., 2006), where they are utilized (e.g. for proteins involved in carbon (C) assimilation) or transiently stored in the form of vegetative storage proteins (Staswick, 1994; Klauer et al., 1996) and as amino acids in vacuoles (Tilsner et al., 2005). Alternatively, the amino acids are directly transferred into the leaf phloem for redistribution to flower, fruit, and seed sinks (Lalonde et al., 2003). Additionally, transfer of amino acids from the xylem to the phloem occurs along the long-distance transport pathway for direct N delivery to growing sinks (Pate et al., 1977).
There are quite a number of papers published on the subject and can be found via Google as āEndocytosis in Plantsā
. This is some time go back to school shit for me 
Once this schedule 3 thing goes through I bet weāll see an explosion of cannabis specific research papers.
itās definitely still in pioneering stage where we do not know everything about itā¦ and I sure wish we did already 
