Search results for "plant physiology"
showing 10 items of 118 documents
Changes of Photosynthesis-Related Parameters and Productivity of Spring Oilseed Rape under Different Nitrogen and Sulphur Fertilizers Supply
2015
Fertilization with essential mineral elements is important to get high quality yield results. The lack of necessary mineral elements in soil can affect oilseed rape plant physiological functions, photosynthesis and plant productivity. Oilseed rape plants have high requirements for nitrogen and as oil crop – for sulphur. The aim of the investigation was to explain changes of chlorophyll a fluorescence parameters in spring oilseed rape leaves and yield changes under nitrogen and sulphur supply. During laboratory experiments changes of chlorophyll a fluorescence parameters and during field experiments changes of yield parameters under different nitrogen and sulphur supply were observed. Labora…
Physiological Aspects of Nitrogen Fertilizer Impact on Latvian Origin Cannabis Sativa L .
2015
The aim of the present study was to evaluate nitrogen fertilizer impact on photosynthesis and yield of hemp, applying modern non-destructive methods. The main object of the investigation – hemp cultivar of Latvian origin ‘Pūriņi’. Laboratory and field experiments showed diverse effects of different nitrogen fertilizer doses on various parameters. Additional nitrogen fertilizer dose of 60 kg ha-1 is most effective as evaluated by chlorophyll content in hemp leaves and changes of chlorophyll a fluorescence parameters. Nitrogen fertilizer negatively affected fiber content in hemp stems, therefore while cultivating hemp only for fiber production use of nitrogen fertilizer should be reduced. Acc…
Interactions between nitrogen fertilization and ozone in watermelon cultivar Reina de Corazones in open-top chambers. Effects on chlorophyll alpha fl…
2006
Watermelon (Citrillus lanants) plants were grown for two consecutive years in open-top chambers with three different ozone concentrations (O-3-free air, O-3 ambient, and air with additional O-3; CFA, NFA, and NFA+O-3) and three nitrogen fertilizer concentrations [0, 14.0, and 29.6 g N per pot; N0, N1, and N2). There was an interaction between ozone and N fertilizer for the major parameters studied. O-3 and N2 treatments led to a significant decrease in maximum efficiency of photosystem 2 (PS2) photochemistry (F-v/F-m), and induced a significant decrease in the actual quantum yield of PS2 (Phi(PS2)), due mainly to the increased closure of PS2 reaction centres (q(P)) and to an increase in the…
Response to long-term NaHCO3-derived alkalinity in model Lotus japonicus Ecotypes Gifu B-129 and Miyakojima MG-20: transcriptomic profiling and physi…
2014
The current knowledge regarding transcriptomic changes induced by alkalinity on plants is scarce and limited to studieswhere plants were subjected to the alkaline salt for periods not longer than 48 h, so there is no information availableregarding the regulation of genes involved in the generation of a new homeostatic cellular condition after long-termalkaline stress.Lotus japonicusis a model legume broadly used to study many important physiological processes includingbiotic interactions and biotic and abiotic stresses. In the present study, we characterized phenotipically the response toalkaline stress of the most widely usedL. japonicusecotypes, Gifu B-129 and MG-20, and analyzed global t…
The effect of kinetin on the photosynthetic apparatus of Sinapis alba
1980
The influence of kinetin during the development of primary leaves of Sinapis alba was investigated. Kinetin treatment (6 ppm) induced an increase of dry weight, of soluble reducing sugars, soluble protein, chlorophylls, carotenoids and cytochrome f; a higher ratio of chlorophyll a to chlorophyll b, higher rates of CO2 fixation per fresh weight and higher activity of nitrite reductase, were also found. These effects are comparable with strong and blue light adaptations. On the other hand, the Hill activity with ferricyanide as the electron acceptor, the rates of CO2 fixation per chlorophyll, the ratios of chlorophyll to cytochrome f and of protein to chlorophyll did not change. Therefore we …
The effect of indole-3-acetic-acid on the photosynthetic apparatus of Sinapis alba
1980
The influence of indole-3-acetic-acid (IAA) during the development of primary leaves of Sinapis alba was studied. IAA treatment (4 ppm ≈ 22.8 μM) caused a decrease of dry weight, soluble reducing sugars, soluble protein, chlorophylls, carotenoids and cytochrome f; it also caused a lower ratio of protein to chlorophyll, a lower ratio of chlorophyll a to chlorophyll b and a higher ratio of chlorophyll per cytochrome f. Furthermore, IAA treatment induced a significantly lower rate of CO2 fixation and a depressed nitrite reductase activity. Similar effects could also be observed in adaptation reactions brought about by red light and low-light (or shade) conditions.
Dracocephalum ruyschiana L. (Numerne, 1888)
1888
Nordischer Drachenkopf finden in lichte Kieferwaldhouge Nemerno. /// Ruiša pūķgalve, atradne: gaiša priežu meža nogāne Numernē. /// Northern Dragon-head, deposit: light pine forest slope in Numerne. [Attēls no LU Muzeja kolekcijas Herbarium Balticum (RIG I); (BOT2791_12)]
Dracocephalum ruyschiana L. (Numerne)
1936
Ruiša pūķgalve; Atradne: Latgalē, Numernē, austrumos no Puriņu mežsarga mājām. /// Northern Dragon-head, deposit: In Latgale, Numerne, east of the Purin forest rangers home. [Attēls no LU Muzeja kolekcijas Herbarium Latvicum (RIG II); (BOT1029_13)]
Dracocephalum ruyschiana L. (Suntažu pagasts)
1938
Ruiša pūķgalve, atradne: Rīgas apriņķa Suntažu pagasta Lielo Kangaru klajās dienvidu nokares piekājē, 43. km no Rīgas. /// Northern Dragon-head, deposit: Riga District Suntažu parish on the southern slope of Lielie Kangari, 43 km from Riga. [Attēls no LU Muzeja kolekcijas Herbarium Latvicum (RIG II), (BOT1029_26) ]
Dracocephalum ruyschiana L. (Ogres Kangari pie Ikšķiles)
1923
Nordischer Drachenkopf finden in sonnigers Abhang des Grandhügels am Ogre - Kanger bei Üxküll. /// Ruiša pūķgalve, atradne: liela kalna saulaina nogāze Ogres Kangaros pie Ikšķiles. /// Northern Dragon-head, deposit: sunny slope of the grand hill on the Ogre - Kanger near Ikskil. [Attēls no LU Muzeja kolekcijas Herbarium Balticum (RIG I); (BOT 2791_7)]