�y��vlog

They show that cambial precursor cells, also known as procambium cells, are specified by a complex molecular network of plant hormones, transcription-factor proteins and microRNAs.

Miyashima et al.3 and Smetana et al.4 studied the plant Arabidopsis thaliana, and report their analysis of the development of a tissue called the cambium, which generates cells of the water- and nutrient-transporting systems — the xylem and phloem, respectively. a, Miyashima and colleagues studied young roots to investigate how procambium cells proliferate.

The studies by Smetana, Miyashima and their respective colleagues analysed the root procambium, which originates in the embryo.

P, pith; PB, primary bast; SB, secondary bast; C, cambium; PR, pith ray; PW, primary wood; SW, secondary wood; PS, procambium strands.

In the first year the wood and the bast are formed directly by the growth and change of the inner and outer cells respectively of the procambium strand, and all such material is called "primary;" but in subsequent years all wood, pith rays, and bast, originate in the cambium, and these growths are called "secondary."