Simeneh Tamrat Alemu; Amsalu Gobena Roro
Abstract
UV-B radiation and EOD light (EOD) quality has both signaling and damaging effects based on the dosage and time of exposure. At highland areas UV-B decreases crop productivity and also light quality increase at high elevation area but EOD light quality effect was not researched based on altitude. Therefore, ...
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UV-B radiation and EOD light (EOD) quality has both signaling and damaging effects based on the dosage and time of exposure. At highland areas UV-B decreases crop productivity and also light quality increase at high elevation area but EOD light quality effect was not researched based on altitude. Therefore, in the present study a field experiment was conducted to investigate the effects of UV-B radiation, EOD light and its exclusion on growth performance and biomass accumulation of sweet potato cultivars on different altitude. The treatments consisting of UV-B exclusion, UV-B+ EOD light exclusion, + UV-B and (control) were studied on two sweet potato cultivars, Kulfo and Hawassa-83. The experimental design was laid out in split plot design with factorial combinations. According to the result, the highest UV-B radiation (1693.0 mw m-2 s-2) was recorded at highlands and the lowest (1107.1 mw m-2 s-2) was recorded at lowland areas. Also EOD light quality was low at lowland. Cultivar and altitude significantly affected growth and net assimilation rate but exclusion only affected growth rate. On dry weight accumulation, cultivar and altitude had high impact but exclusion affected tuber and specific leaf dry weight. Exclusion by cultivar interaction affected net-assimilation rate and specific leaf dry weight but exclusion by altitude interactions affected growth rate, net-assimilation rate and tuber dry weight. Altitude by cultivar doesn’t have any significant effect on growth performance but it has considerable effect on dry biomass accumulation. In conclusion, high UV-B at highland and low EOD time light quality at lowland negatively influenced growth performance and biomass of sweet potato cultivars
Fatemeh Nejadhabibvash; Esmaeil Rezaei Chiyaneh; Alireza Pirzad
Abstract
This study was conducted to investigate the effect of altitudinal gradients on the anatomy of Salvia limbata C.A.Mey. (Lamiaceae). . The S. limbata species were collected from their natural habitats from various regions of West Azerbaijan province in Iran. The thickness of cuticle, collenchymas, ...
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This study was conducted to investigate the effect of altitudinal gradients on the anatomy of Salvia limbata C.A.Mey. (Lamiaceae). . The S. limbata species were collected from their natural habitats from various regions of West Azerbaijan province in Iran. The thickness of cuticle, collenchymas, phloem, xylem and pith of stem and leaf thickness were measured. Moreover, width, length and number of stomata on both adaxial and abaxal epidermal surfaces were analyzed. Statistical analyses were done on a completely randomized design. The results indicated that by increasing altitude leaf thickness increased from 239.1 to 300.1 µm. Number of leaf epidermal cells was also increased in higher altitude on both upper (4.30 to 5.61) and lower (1.05 to 6.55) epidermal surfaces. The results confirmed that more stomata on both adaxial and abaxial epidermis in high altitude samples were associated with presence of narrower and longer stomata on their leaves. Significant differences in the cuticle, collenchyma, xylem, phloem and parenchymatous pith thickness in the stem were observed in all the six studied populations. At higher altitudes thicker cuticle, increased number of collenchyma and wider xylem, phloem and parenchymatous pith were detected. Plants in Mahlamlu region had the thickest studied parameters and Plants in Kabudan Island region had the thinnest tissues.
