Short Shoot Growth and Reproduction Response to Light Conditions Vary with Order Branching in the Proximal Part of C. atlantica Crown

Abstract

is study compared the effects of shading in individual branch orders 2 and 3 on the needle survival, growth, and reproduction of five categories of short shoots of the proximal part of wild Atlas cedar (Cedrus atlantica (Endl.) G. Manetti ex Carrière). e sun exposure did not affect the number of short shoots in the two branch orders, whereas light compared to shade only stimulates the unbranched short shoot elongation of the branch order 3. e impact of shade exposure compared to sun on the loss of needles depends on the order of branching; it is weak to order 2 and increases to higher order. is effect in the branch order 3 is achieved by a significant decrease of the fallen leaf number in the unbranched short shoot SSnr and the short shoot SS/T worn by Twigs while in the branch order 2 only short shoot SS (nr + r) loses significantly few needles. In terms of short shoot extension and needle loss, the SS/Tof the branch order 3 behaves in the same way as the SS (nr + r) of the branch order 2. e shadow compared to sunlit only decreases significantly the production of pollen strobili of the branch order 2. Close relationships between short shoot extension, leaf life span, and pollen strobili production of axillary products in the proximal part of C. atlantica crown were found.

Morphological and Anatomical Characterization of Ecotype Needles of Cedrus atlantica in Morocco

“…is difference may be due to the use of the needles from the long shoots, which are generally longer than those of whorls. On the other hand, values obtained in the present study are still low even when compared to those of C. atlantica whorl needles reported by Saouab and Bendriss Amraoui [53] or to those of the needles of young seedlings of 2-5 years in the Middle Atlas of Morocco and higher than those of 16 months and 2 years of Algerian provenances [54]. e values of the average length of needles of the populations of Aït Ayach and Aït Oufella that were found to be included in the margin of length 10.77-11.06 mm are lower than those found in this study Tamrabta and Moudemame ones (Table 2).…”

“…On seedlings of provenances from the High Atlas (Tounfite and Assaka) grown in Maures, Arbez et al [54] found values of the average length of needles of 23.8 and 19.5 mm, respectively. ese comparisons show that the average length of cedar needles is highly dependent on shoot growth and environmental conditions [53], making it one of the most important varietal selection criteria for cedar if it was taken at a fully developed stage. us, the ontogenetic variations of the needle traits may not mislead when we use mature needles to distinguish the ecotype in this study.…”