Effects of watering levels and light intensities on seedling vigour of African star apple (Chrysophyllum albidum g. Don)

A 3x2 factorial experiment was laid down in Completely Randomized Design with three replications to assess the effects of watering levels (30, 80 and 140 mL/seedlings) and light intensities (25 and 50 %) on seedling vigour of C. albidum. Watering levels and light intensities significantly (P<0.05) enhanced the seedling growth of C. albidum. Widest leaf area (4.16 cm2), highest root dry weight (0.14 g), highest leaf dry weight (0.24 g) and highest total dry weight (0.52 g) were recorded for seedlings subjected to 80 mL/seedling watering level. Seedlings planted under 50 % light intensity gave higher value of leaf area (2.71 cm2), root dry weight (0.13 g), leaf dry weight (0.25 g), total dry weight (0.53 g) and relative turgidity (74.82 %) compared to those subjected to 25 % light intensity. Highest leaf dry weight (0.30 g), shoot dry weight (0.17 g) and total dry weight (0.59 g) were recorded in seedlings subjected to 80 mL/seedling watering level and exposed to 50 % light intensity. Subjection of C. albidum seedlings to a combination of 80 mL/seedling watering level as well as 50 % light intensity enhanced its growth. The study therefore recommends subjection of C. albidum seedlings to 80 mL /seedling watering level and 50 % light intensity for mass production of its seedlings for agro-forestry systems. Key words: Watering regime, Light intensity, Seedling growth, Propagation, Agro-forestry Syste

The Dimeric Pyramidal Cu 2 O 6 (H 2 O) 2 Unit - A Structural Invariant of a Homologous Series of Copper-Layered Phosphonates

International audienceTwo new layered copper hybrid materials, namely, the copper thiophene-2,5-diphosphonate [Cu2(H2O)2(O3P–C4H2S–PO3)] (Pnma; a = 7.525 Å, b = 18.292 Å, c = 7.520 Å) and the copper 3-fluorophenylphosphonate Cu(H2O)PO3–C6H4F (P21/c; a = 14.305 Å, b = 7.550 Å, c = 7.479 Å, β = 92.32°), have been synthesized. These compounds belong to the large homologous Cu(H2O)PO3R/[Cu2(H2O)2(O3P–R–PO3)] series, the structure of which is dictated by the presence of isolated dimeric pyramidal Cu2O6(H2O)2 units. The role of the Cu/H2O molar ratio of 1 in the stabilization of such a structure is discussed in connection with the Jahn–Teller effect of the copper cation. The study of the magnetic behavior of polycrystalline samples of the two compounds has revealed antiferromagnetic coupling between the copper ions. The interactions within the dimeric unit were estimated by the Bleaney–Bowers law with the spin Hamiltonian H = –JSCu1SCu2 + gβHS: J = –6.27 cm–1 for [Cu(H2O)PO3]2C4H2S, and J = –6.07 cm–1 for Cu(H2O)PO3–C6H4F