scholarly journals Role of Potassium in Carbon Dioxide Assimilation in Medicago sativa L

1979 ◽  
Vol 63 (5) ◽  
pp. 878-881 ◽  
Author(s):  
Timothy R. Peoples ◽  
David W. Koch
Keyword(s):  
Carbon Dioxide ◽  
Medicago Sativa ◽  
Carbon Dioxide Assimilation ◽  
Medicago Sativa L

THE ROLE OF KETO ACIDS IN PHOTOSYNTHETIC CARBON DIOXIDE ASSIMILATION

1956 ◽  
Vol 34 (1) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Sugar Beet ◽  
Aspartic Acid ◽  
Pyruvic Acid ◽  
Carbon Dioxide Assimilation ◽  
Free Air ◽  
Keto Acids ◽  
Photosynthetic Carbon

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.

THE ROLE OF KETO ACIDS IN PHOTOSYNTHETIC CARBON DIOXIDE ASSIMILATION

1956 ◽  
Vol 34 (3) ◽  
pp. 511-519 ◽  
Author(s):  
G. H. N. Towers ◽  
D. C. Mortimer
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Sugar Beet ◽  
Aspartic Acid ◽  
Pyruvic Acid ◽  
Carbon Dioxide Assimilation ◽  
Free Air ◽  
Keto Acids ◽  
Photosynthetic Carbon

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.

An overview of the role of lucerne (Medicago sativa L.) in pastoral agriculture

2012 ◽  
Vol 63 (9) ◽  
pp. 734 ◽  
Author(s):  
J. H. Bouton
Keyword(s):  
Medicago Sativa ◽  
Complex Traits ◽  
Production Systems ◽  
Bioenergy Feedstock ◽  
Continue Development ◽  
Breeding Programs ◽  
Grazing Tolerance ◽  
History Of ◽  
Medicago Sativa L

Pastoral agriculture is unique among the world’s agricultural production systems. Lucerne (also known as alfalfa), Medicago sativa L. subsp. sativa, has a long history of playing a very important role in pastoral agriculture. That role is expanding outside traditional hay and grazing production systems into sprouts for salads, nutritional supplements, and bioenergy feedstock. It is also the forage legume of choice for delivery of new traits via biotechnologies. The use of biotechnologies in lucerne improvement will cause re-examination of research methods and will require unique collaborations that are both interdisciplinary and even cross-institutional. The Consortium for Alfalfa Improvement (CAI) is discussed as a model for this type of collaboration. Breeding programs will continue development of cultivars with the proper fall (autumn) dormancy, a broad genetic base for pest resistance, increased local adaptation, persistence, and yield, while also adding new complex traits to these base traits. Increasing nutritional quality via down-regulation of lignin genes and increasing persistence via grazing tolerance, drought tolerance, and tolerance to acid, aluminium-toxic soils are discussed as examples of the potential impacts and challenges surrounding incorporation of complex traits. However, it is the potential for lucerne to become a major part of tropical or subtropical production systems or even an important adjunct to overcome deficiencies in the widely used perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) temperate systems that begs further attention.

Influence de la température d'endurcissement sur la tolérance au gel de la luzerne et sa teneur en sucres, amidon et proline

1991 ◽  
Vol 71 (3) ◽  
pp. 737-747 ◽  
Author(s):  
Annick Bertrand ◽  
Roger Paquin
Keyword(s):  
Medicago Sativa ◽  
Cold Tolerance ◽  
Sugar Content ◽  
Frost Tolerance ◽  
Proline Content ◽  
Starch Degradation ◽  
Limiting Factor ◽  
Total Sugar Content ◽  
Medicago Sativa L

The increased sugar and starch in crowns and roots during hardening is considered a limiting factor for the acquisition of cold tolerance in alfalfa (Medicago sativa L.). We wanted to determine the effect of a decrease in carbohydrate on cold tolerance. Alfalfa plants (Medicago sativa L.) were hardened at 1 °C or −2 °C during the day and at 10 °C or 15 °C during the dark while control plants were kept continuously at 1 °C or −2 °C. Hardening alfalfa at 10 °C and 15 °C during darkness decreased the total sugar content while it increased at 1 °C and −2 °C. However, frost tolerance and growth of the plants were not changed by raising the night temperature to 10 and 15 °C. The sugar increase corresponded in general to a starch degradation, mainly in the crowns. In plants hardened at −2 °C the proline content was higher in the leaves and lower in crowns. The opposite was observed in plants hardened at 10 and 15 °C during darkness. However, during hardening at −2 °C, we observed the desiccation of leaves and an increase in the proline content. We discuss the role of sugars as promoting agents for the acquisition of frost tolerance. Key words: Alfalfa, frost tolerance, sugars, starch, proline, hardening

scholarly journals The rôle of the young lucerne plant in determining the infection of the root by the nodule-forming bacteria

1929 ◽  
Vol 104 (732) ◽  
pp. 481-492 ◽  
Keyword(s):  
Medicago Sativa ◽  
Culture Solution ◽  
Nodule Bacteria ◽  
True Leaf ◽  
Plant Culture ◽  
Medicago Sativa L ◽  
The Relationship

Observations have been made at Rothamsted over a period of about five years upon the development of nodules on young seedlings of lucerne (Medicago sativa, L.). Some thousands of seedlings have been examined in various experiments and it was found to be the rule that the first appearance of nodules coincided with that of the expansion of the first true leaf. When lucerne is sown under summer glasshouse conditions, in pots of soil or sand, the seedlings are up in from 3 to 5 days, and in 8 to 12 days the first true leak becomes visible. This is at first closed, but in 8 to 12 days from the date of sowing it opens out (fig. 1). The following experiment illustrates the relationship between the opening of the List leak and the appearance of nodules. Lucerne seed, inoculated with nodule bacteria was sown in 12 pots, each containing about 8 pounds of sand, and these were watered with a plant-culture solution free from nitrogen.* Five days after sowing the seedlings were up, and in another 4 the first true leak, still closed, could be seen on most of them. The appearance of nodules and the opening of the first true leaves is shown in fig. 2, where each point represents observations made upon 20 seedlings, 10 from each of duplicate pots. The general agreement in the time of appearance of nodules and in the opening of the first true leaves is evident.

scholarly journals The Role of Different Daily Irradiations on Shoot Growth and Root/Shoot Ratio in Lucerne (Medicago sativa L.)

1991 ◽  
Vol 68 (4) ◽  
pp. 329-335 ◽  
Author(s):  
S. PHILIPPOT ◽  
J. M. ALLIRAND ◽  
M. CHARTIER ◽  
G. GOSSE
Keyword(s):  
Medicago Sativa ◽  
Shoot Growth ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Medicago Sativa L
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