Effekter av UV-stråling på vekst og utvikling hos planter dyrket i ulike klimaregimer

Ultraviolet (UV) radiation has various effects on the growth, morphology, and biochemical composition of plants. Currently, there is an increasing interest in the manipulation of UV radiation in glasshouses, polythene tunnels, and other protected horticultural environments. In this study, UV radiation was manipulated by the use of UV lamps and filters with different UV-transmittance. The main objective was to study the effects of UV radiation under different climatic regimes in the regulation of plant growth and development, biomass production and yield, postharvest life, and the content of secondary metabolites and plant hormones.Ultrafiolett (UV) stråling har effekt på planters vekst, morfologi og kjemisk innhold. Det er stor interesse for å manipulere UV stråling i kommersiell produksjon av planter i veksthus, plasttunneler og i andre typer dyrkingssystemer med kontrollert klima for å påvirke viktige planteprosesser. I dette arbeidet ble UV stråling manipulert ved filtrering av naturlig sollys gjennom ulike filter og ved bruk av UV lamper. Hovedformålet var å studere effekter av UV på plantevekst og utvikling, biomasseproduksjon og avling, holdbarhet, samt innholdet av sekundære-metabolitter og plantehormoner.Publisering av artikler uklar

Impact of waterlogging stress on grafted avocado (Persea americana) seedlings growth and physiological performance

AbstractAgricultural fields prone to waterlogging condition induce physiological stress on fruit trees as it affects root respiration and nutrient uptake. However, the information on the growth performance of avocado under waterlogging condition is limited, particularly in terms of morphological and physiological performances. Therefore, this study was designed to evaluate the performance of avocado rootstocks under different waterlogging levels under shade condition. The experiment was conducted using a complete randomized design with factorial arrangement using Ettinger variety as scion that was grafted on Guatemalan and Mexican rootstock races at three waterlogging levels (50%, 75% and 100%) in three replications. The result showed that morphological growth of avocado grafted on Guatemalan race outscored in number of buds, shoot growth, rootstock elongation and scion shoot tip growth compared to the one grafted on Mexican race. Similarly, photosynthesis, transpiration and stomata conductance were significantly affected by the races, waterlogging levels and interaction of the two main factors. The result indicated that the Guatemalan race significantly improved photosynthesis, transpiration, stomata conductance and water use efficiency nearly by 50% in all waterlogging levels as compared to the one grafted on Mexican race. However, the smallest transpiration and water use efficiency were recorded at 100% waterlogging level from the Mexican race. Generally, the study revealed that Guatemalan race used as rootstock gave a strong morpho-physiological performance as compared to the Mexican race. Similarly, waterlogging level at 75% induced strong morphological and physiological performances in Guatemalan race compared to the seedling subjected to 50% and 100% waterlogging. Thus, the finding revealed that the Guatemalan race can be a potential rootstock under waterlogging/saturated soil condition in loamy sand soil texture

Intercropping and Rhizobium Inoculation Affected Microclimate and Performance of Common Bean (Phaseolus vulgaris L.) Varieties

A field experiment was carried out at Hawassa, during the 2020 cropping season with the objective to evaluate the impact of maize-common bean intercropping and Rhizobium inoculation on microclimate, growth, and yield of common bean varieties. Treatments consisting of two common bean varieties, two levels of inoculation and three spatial arrangements of common bean with another sole maize were laid out in a factorial arrangement in a randomized complete block design (RCBD) with three replications. The results revealed that the main effect of spatial arrangements highly significantly (P < 0.001) affected soil and leaf temperature. Soil moisture content was improved under intercropped plots compared with sole cropping. The intensity of light and qualities, such as red, far-red, and photosynthetically active radiations (μmol m−2 s−1) and ultraviolet rays (UV)-A, UV-B (W m−2), were reduced under intercropping as compared to the sole. Interaction effects of variety, spatial arrangements, and inoculation significantly (P < 0.01) affected plant height and leaf area index. Inoculated sole Nassir outperformed for plant height and leaf area index. Inoculated sole Hawassa Dume variety performed best for nodule number plant−1, nodule dry weight plant−1, pods number plant−1, 100 seed weight, grain yield, and above-ground biomass yield. The highest grain yield (2.8 t ha−1) was recorded from inoculated sole Hawassa Dume. However, considering the equivalent ratio (LER), intercropping with one maize row to two haricot bean rows spatial arrangements was productive by 62% more than sole cropping (total land equivalent ratio of 1.62%)

Effect of Moisture Stress on Physiological and Yield Responses of Common Bean Varieties at Lath House Condition, Hawassa University, Southern Ethiopia

Common bean is one of the most traditional foods, with social and economic importance, and is suitable for food security due to its short growing cycle and adaptability to different cropping systems. However, various constraints like biotic and abiotic factors reported for the low productivity of the crop. Therefore, the study was designed to identify the common bean varieties’ response on physiological properties and yield performance under different irrigation intervals in Lath House condition at Hawassa University, Ethiopia, from June, 2020, to September, 2020. The experiment was laid out in a completely randomized design with a factorial combination of seven common bean varieties (Awash-1, Awash-2, Dursitu, Fedis, Gofta, Nasir, and Tinike) and three moisture levels, eight day irrigation interval, four day irrigation interval, and daily watering with three replication. There was a significant main and interaction effects among the measured parameters. From those significantly affected parameters, the highest stomata numbers (25) were recorded from the Dursitu variety with a daily irrigation interval. The longest stomata aperture was observed with Gofta (133.76 nm) and Fedis varieties (131.13 nm) to daily irrigation and four day irrigation intervals, respectively. A wider stomata aperture was found in the Awash-1(12.6 nm) variety on a daily irrigation interval, and maximum stomata conductance (193.67) was obtained in the Tinike variety treated with a four day irrigation interval. The maximum relative leaf moisture content (96%) was found on the Awash-1 variety at a four day irrigation interval. Maximum water use efficiency was obtained from the Awash-1 (3.95) variety, which is an insignificant variation with the Awash-2 (3.85) and Gofta varieties (3.85) at a four day irrigation interval. Among the varieties, the highest photosynthesis rate (10.43 μmol·m−2·s−1) and transpiration rate (5.42 mmol·m−2·s−1) were obtained in the Gofta variety treated by a four day irrigation interval. In the photosynthetic pigment analysis, the highest leaf chl-a, chl-b, and chl-a + b concentration was recorded at 2.4 μg/ml, 1.53 g/ml, and 3.93 μg/ml, respectively, in the Gofta variety irrigated at a four days interval. The highest (0.586) chlorophyll fluorescence was obtained in the eight day irrigation interval. The highest proline content was found from the Awash-1 (0.78) variety regarding to drought stress condition. The highest pods plant−1 (9) and seed pod−1 (5) was found in the Awash-2 and Awash-1 varieties, respectively, at a four days irrigation interval and the highest main effect of 100 SW (39.48 g), (28.6 g) was found in the Fedis variety and at a four day irrigating interval, respectively. The maximum yield was obtained from the varieties Awash-1 (7.8 g plant−1) and Gofta (7.36 g plant−1) with a four day irrigated interval and they are also superior at drought condition and Awash-2 varieties are enhanced at waterlogging condition as compared to the other varieties