scholarly journals Nodule and Leaf Nitrate Reductases and Nitrogen Fixation in Medicago sativa L. under Water Stress

1982 ◽  
Vol 69 (2) ◽  
pp. 479-482 ◽  
Author(s):  
P. Aparicio-Tejo ◽  
Manuel Sánchez-Díaz
Keyword(s):  
Nitrogen Fixation ◽  
Water Stress ◽  
Medicago Sativa ◽  
Medicago Sativa L ◽  
Leaf Nitrate ◽  
Nitrate Reductases

EFFECTS OF INITIAL HARVEST DATE ON PRODUCTIVITY AND PERSISTENCE OF ALFALFA AND BROMEGRASS

1972 ◽  
Vol 52 (5) ◽  
pp. 801-804 ◽  
Author(s):  
J. D. McELGUNN ◽  
D. H. HEINRICHS ◽  
R. ASHFORD
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Taraxacum Officinale ◽  
Bromus Inermis ◽  
Harvest Date ◽  
Mixed Stands ◽  
Medicago Sativa L ◽  
Made In

Alfalfa (Medicago sativa L.), bromegrass (Bromus inermis Leyss.), and a mixture of the two were grown on irrigated land and subjected to six defoliation schedules in which the initial cutting date varied in time. Delaying the initial defoliation until mid-June resulted in greatest seasonal yield even though the last cutting in this schedule was made in the 1st week of September, usually considered somewhat late for cutting in Saskatchewan. Nitrogen at the rate of 112 kg/ha doubled the yield of bromegrass but did not increase the yield of the alfalfa–bromegrass mixture, indicating that nitrogen fixation was adequate for the crop. Alfalfa and the alfalfa–bromegrass mixtures yielded about 50% more forage than the N-fertilized bromegrass and three times as much as unfertilized bromegrass. At the end of the experiment, dandelions (Taraxacum officinale Weber) had invaded pure stands of alfalfa but not mixed stands of alfalfa and bromegrass.

WATER STRESS OF ALFALFA DURING STRESS AND RECOVERY

1982 ◽  
Vol 62 (3) ◽  
pp. 639-647 ◽  
Author(s):  
ROBERT G. HALL ◽  
KENNETH L. LARSON
Keyword(s):  
Water Stress ◽  
Medicago Sativa ◽  
Developmental Stages ◽  
Water Status ◽  
Leaf Conductance ◽  
Daily Maximum ◽  
Full Bloom ◽  
Water Deficits ◽  
Medicago Sativa L

Water status and stomatal activity of alfalfa (Medicago sativa L.) cultivars Cody and Sonora were evaluated under greenhouse conditions during water stress and recovery at the 7th leaf and full bloom developmental stages. Following onset of stress predawn LWP declined linearly and plants remained visibly wilted as potentials approached 1.8 MPa in both cultivars and developmental stages. Significant (P = 0.05) relationships were evident between predawn LWP and days after onset of stress (R2 > 0.90) and between daily maximum leaf conductance (KL) and predawn LWP (R2 > 0.80) when averaged over both cultivars at each stage. Recovery of LWP of both cultivars was complete within 24 h after rewatering. Ability of stomatal activity to recover was similar for both cultivars and developmental stages and was attained within 32 h after rewatering. Results indicate that these cultivars, which differ in winterhardiness, do not differ in water status and stomatal activity with increasing water deficits.

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