Figure 1.

Expression of PtLIM genes using semi quantitative RT-PCR analysis in poplar trees. A. Vegetative organs: Three straight young poplars (Populus tremula × P. alba) producing normal wood were cultivated in the greenhouse for three months. Phloem and bark (PB), cambial zone (CZ), developing xylem (DX) and mature xylem (XM) were scraped from the stem. To study primary growth, young green portions of stems (YS) were collected just below the apex. Leaf vascular tissues like petioles (Pe) and main vessels (V) were separated from limbs (L). Two-weeks-old dark-grown calli (C) were also harvested. B. Reproductive organs: female flowers were dissected from mature poplar trees (Populus nigra) growing in the nursery and the stigma (Sg) were separated from the ovary and style (OS). Two different developmental stages were analyzed on male flowers: partially-open flowers (St1) at an early developmental stage, and fully-open flowers at pre-anthesis stage (St2). Mature pollen (P) and germinated pollen (GP) were also analyzed, as well as seeds (S) separated from both the cottony fibers (F) and the capsule protecting seeds (Ca). 18S rRNA signals are indicative of the total RNA quantity in each sample