Search results for "plant physiology"

Aleksandra Zāmeļa 1925. gadā ievāktais mazā zvaguļa herbārijs

2019

Raksts par 2019. gada auga mazā zvaguļa Rhinanthus minor herbāriju, ko 1925. gada 20. jūnijā ievācis latviešu botāniķis un iedzimtības pētnieks Aleksandrs Zāmelis, un kas glabājas Latvijas Universitātes Muzeja Botānikas un mikoloģijas kolekciju Latvijas Herbārijā (Herbarium Latvicum).

Foliar Spraying with Zineb Increases Fruit Productivity and Alleviates Oxidative Stress in Two Tomato Cultivars

2000

The effects of foliar spraying of the dithiocarbamate zineb on two cultivars of tomato grown in the field in a site with high ozone concentrations were studied by means of biomass assessment, antioxidant enzyme assays, lipid peroxidation, and chlorophyll fluorescence measurements. Zineb prevented the peroxidation of membrane lipids and decreased the activity of scavenging enzymes, which suggests that plants sprayed with zineb are subjected to lower oxidative stress than controls. The beneficial effects of zineb protection is the utilization of a larger fraction of absorbed radiant energy in photosynthesis and a larger fruit yield in plants of both cultivars.

Dracocephalum ruyschiana L. (pie Prensas (Antonopole))

1883

Nordischer Drachenkopf: Heidekieferwald bei Presna (Antonopol); Lichte Waldhange bei Nummern (1888.10.07.) /// Ruiša pūķgalve; Atradne: viršu priežu mežs pie Prensas (Antonopole); gaiša meža nogāze pie Numernes. /// Northern Dragon-head, deposit: heather pine forest near Prensa (Antonopole); a bright forest slope near Numerne. [Attēls no LU Muzeja kolekcijas Herbarium Latvicum (RIG II); (BOT1029_21)]

Olfactory attraction of the hornet Vespa velutina to honeybee colony odors and pheromones.

2014

19 pages; International audience; Since the beginning of the last century, the number of biological invasions has continuously increased worldwide. Due to their environmental and economical consequences, invasive species are now a major concern. Social wasps are particularly efficient invaders because of their distinctive biology and behavior. Among them, the yellow-legged hornet, Vespa velutina, is a keen hunter of domestic honeybees. Its recent introduction to Europe may induce important beekeeping, pollination, and biodiversity problems. Hornets use olfactory cues for the long-range detection of food sources, in this case the location of honeybee colonies, but the exact nature of these c…

Pflanzengattungen der Livländische Flora

1840

Dr. biol. Edgars Vimba: biobibliogrāfiskais rādītājs

2005

Advisor: Paukšēna Diāna

Cadmium and nickel accumulation in rice plants. Effects on mineral nutrition and possible interactions of abscisic and gibberellic acids

1994

Rice plants accumulate high quantities of Cd and Ni when grown for 10 days in a medium containing these heavy metals. Accompanying Cd and Ni uptake, a decrease in shoot and root length was observed, though dry matter accumulation was not affected accordingly. Metal treatments also induced a decrease in K, Ca and Mg contents in the plants, particularly in the shoots, indicating that Cd and Ni interfered not only with nutrient uptake but also with nutrient distribution into the different plant parts. Addition of abscisic acid (ABA) or gibberellic acid (GA3) to the external solution could not overcome the depressing effects of the metals on nutrient acquisition, and even induced a further decr…

Influence of cadmium and nickel on growth, net photosynthesis and carbohydrate distribution in rice plants

1992

Six day old rice seedlings (Oryza sativa L. cv. Bahía) were grown for 5 or 10 days in a nutrient solution with either Cd (0.01, 0.1 mmol/l) or Ni (0.1, 0.5 mmol/l). Both Cd and Ni reduced the length of shoots and roots depending on the concentration and type of ion tested. On the other hand, the dry weight to fresh weight ratio was increased by heavy metal treatments, especially in the aerial part of 0.5 mmol/l Ni treated plants. The application of 0.1 mmol/l Cd and 0.5 mmol/l Ni to the seedlings produced an inhibition of the transport of carbohydrate reserves from the seeds from which plants were developing, to the rest of the plant. Net photosynthesis was also inhibited in treated plants.…

Exposure to moderate concentrations of tropospheric ozone impairs tree stomatal response to carbon dioxide.

2011

With rising concentrations of both atmospheric carbon dioxide (CO(2)) and tropospheric ozone (O(3)), it is important to better understand the interacting effects of these two trace gases on plant physiology affecting land-atmosphere gas exchange. We investigated the effect of growth under elevated CO(2) and O(3), singly and in combination, on the primary short-term stomatal response to CO(2) concentration in paper birch at the Aspen FACE experiment. Leaves from trees grown in elevated CO(2) and/or O(3) exhibited weaker short-term responses of stomatal conductance to both an increase and a decrease in CO(2) concentration from current ambient level. The impairement of the stomatal CO(2) respo…

Isolation and culture of grape vine cv. Chardonnay leaf protoplasts

1990

Experimental conditions were established that resulted in high yields and good viability of the protoplasts obtained from leaves of Vitis vinifera, cv. Chardonnay regenerated in vitro by somatic embryogenesis. The effect of factors of the culture medium and various environmental conditions upon the frequency of cell division has been examined, and a method of culture is described by which protoplasts were induced to begin division. Most protoplasts obtained in this way regenerated cell walls within the first few days and cell division occurred after 10 days of culture in a liquid medium. Some cells have divided two or even three times. Nevertheless, the cells did not continue dividing beyon…