EFFECTS OF TEMPERATURE ON PHOTOSYNTHATE PARTITIONING IN ALFALFA

This study was conducted to examine the effects of three temperature regimes (12/2 °C, 21/8 °C, and 34/25 °C day/night) on photosynthate partitioning in alfalfa (Medicago sativa L.). Plants were grown under greenhouse conditions for approximately 3 mo and then clipped back. When regrowth was at the bud stage, the plants were placed in growth chambers at the three temperatures, all having a photoperiod of 14 h. Two hours after the onset of the photoperiod of the second day, foliar application of 14C-labelled urea was used to provide a source of 14CO2 for tracing the movement of photosynthate from the source leaf to other parts of the alfalfa plant. Plants were harvested 24 h later and each plant was subdivided into six portions. The plant parts included the source leaf, treated upper shoot, treated lower shoot, untreated shoot, crown and roots. The percent of 14C exported of the total recovered radioactivity by the source leaf increased as temperature increased. As temperature increased, radioactivity recovery was increased in treated upper shoot, untreated shoots, and roots. The highest recovery of 14C by the crown was at 21/8 °C. followed by those in 12/2 °C and 34/25 °C, respectively. Total 14C recovered from the treated lower shoot was decreased as temperature increased.Key words: Relative specific activity (RSA), total plant radioactivity, translocation, 14C, Medicago sativa L., alfalfa

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Insecticidal Active Rotenoids from Plant Parts and Callus Culture of Medicago sativa L. from a Semiarid Region of India (Rajasthan)

Current Bioactive Compounds ◽

10.2174/1573407215666190628145149 ◽

2020 ◽

Vol 16 (6) ◽

pp. 937-941

Author(s):

Sharad Vats ◽

Preeti Mehra

Keyword(s):

Medicago Sativa ◽

Callus Culture ◽

Point Of View ◽

Semiarid Region ◽

Disease Vectors ◽

Vector Borne Diseases ◽

Plant Parts ◽

Resistant Varieties ◽

Medicago Sativa L

Background: Vector-borne diseases are quite prevalent globally and are one of the major causes of deaths due to infectious diseases. There is an availability of synthetic insecticides, however, their excessive and indiscriminate use have resulted in the emergence of resistant varieties of insects. Thus, a search for novel biopesticide has become inevitable. Methods: Rotenoids were isolated and identified from different parts of Medicago sativa L. This group of metabolites was also identified in the callus culture, and the rotenoid content was monitored during subculturing for a period of 10 months. Enhancement of the rotenoid content was evaluated by feeding precursors in a tissue culture medium. Results: Four rotenoids (elliptone, deguelin, rotenone and Dehydrorotenone) were identified, which were confirmed using spectral and chromatographic techniques. The maximum rotenoid content was found in the seeds (0.33±0.01%), followed by roots (0.31±0.01%) and minimum in the aerial parts (0.20±0.05%). A gradual decrease in the rotenoid content was observed with the ageing of subcultured tissue maintained for 10 months. The production of rotenoids was enhanced up to 2 folds in the callus culture using amino acids, Phenylalanine and Methionine as precursors as compared to the control. The LC50 value of the rotenoids was found to be 91 ppm and 162 ppm against disease vectors of malaria and Dracunculiasis, respectively. Conclusion: The study projects M. sativa as a novel source of biopesticide against the disease vectors of malaria and Dracunculiasis. The use of precursors to enhance the rotenoid content in vitro can be an effective venture from a commercial point of view.

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Inter- and intra-varietal variation in aerobic methane emissions from environmentally stressed pea plants

Botany ◽

10.1139/cjb-2018-0126 ◽

2018 ◽

Vol 96 (12) ◽

pp. 837-850 ◽

Cited By ~ 2

Author(s):

Awatif M. Abdulmajeed ◽

Mohammad I. Abo Gamar ◽

Mirwais M. Qaderi

Keyword(s):

Stress Factors ◽

Interactive Effects ◽

Controlled Environment ◽

Uvb Radiation ◽

Pisum Sativum L ◽

Temperature Regimes ◽

Varietal Variation ◽

Growth Chambers ◽

Effects Of Temperature ◽

Two Temperature

Environmental stress factors can influence methane (CH4) emissions from plants. There are a few studies on the interactive effects of stress factors on plant aerobic CH4, but none on the comparative evaluation of CH4 emissions between and among plant varieties. We examined the effects of temperature, UVB radiation, and watering regime on CH4 emissions from 10 pea (Pisum sativum L.) varieties first and then selected two varieties with the highest (237J Sundance; var. 1) and lowest (422 Ho Lan Dow; var. 2) emissions for further studies. Plants were grown in controlled-environment growth chambers under two temperature regimes (22 °C / 18 °C and 28 °C / 24 °C, 16 h light / 8 h dark), two UVB levels (0 and 5 kJ·m−2·d−1), and two watering regimes (well-watered and water-stressed) for 14 days, after one week of growth under 22 °C / 18 °C. Higher temperatures and water stress increased CH4 emissions, and increased emission was associated with stress. Pea varieties varied in growth and CH4 emissions; var. 1 was more stressed and had higher emission than var. 2. In the stressed variety, the water-stressed plants grown under higher temperatures at UVB5 had the highest CH4 emission, whereas the well-watered plants grown under lower temperatures at UVB5 had the lowest emission. We conclude that climatic stress conditions increase CH4 emissions, which vary with plant varieties.

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Zur Biogenese der Isoflavone

Zeitschrift für Naturforschung B ◽

10.1515/znb-1964-0704 ◽

1964 ◽

Vol 19 (7) ◽

pp. 569-571 ◽

Cited By ~ 24

Author(s):

Hans Grisebach ◽

Wolfgang Barz

Keyword(s):

Medicago Sativa ◽

Specific Activity ◽

Medicago Sativa L

4.2′.4′-trihydroxy-chalcone-4′-glucoside-[β-14C] (II) is incorporated into the coumarano-coumarine coumestrol (I) in lucerne (Medicago sativa L.) in the same manner as it is into isoflavones. These results lead to the conclusion that the chalcone is a common intermediate in the biosynthesis of both coumestrol and the isoflavones. The dilution of the specific activity of the chalcone upon incorporation into I is somewhat greater than upon incorporation into the isoflavones formononetin and daidzein, which also occur in lucerne.

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YIELDS AND ELEMENTAL COMPOSITION OF ALFALFA PLANT PARTS AT LATE BUD UNDER TWO FERTILITY LEVELS

Canadian Journal of Plant Science ◽

10.4141/cjps75-009 ◽

1975 ◽

Vol 55 (1) ◽

pp. 69-75 ◽

Cited By ~ 12

Author(s):

R. S. ROMINGER ◽

DALE SMITH ◽

L. A. PETERSON

Keyword(s):

Medicago Sativa ◽

Elemental Composition ◽

Stem Segment ◽

Alfalfa Plant ◽

Plant Parts ◽

Significant Difference ◽

Distribution Of Elements ◽

Medicago Sativa L ◽

Lower Stem ◽

Stem Segments

The current study was initiated to ascertain distribution of elements in various parts of alfalfa (Medicago sativa L.) and whether differential accumulation occurred when a fertilizer was applied. Rows of Vernal alfalfa were fertilized in late April with a mixture of K2SO4, KCl, K2HPO4, MgSO4, MnSO4, Na2B4O7, CuSO4, and ZnSO4. Control rows were not fertilized. Shoots were removed at late bud and separated by 10-cm segments into leaves and stems. Upper 15 cm of roots also were sampled. No significant difference existed between unfertilized and fertilized plants in dry weights of comparable plant parts, except for significantly more leaves on next-to-bottom segment of fertilized shoots. Total leaves at both fertility levels contained higher concentrations of S, P, Mg, Ca, Zn, Mn, B, N, and Cu than total stems or roots. Total stems were highest in K and Cl. Total roots at both fertility levels contained higher concentrations of Na, Fe, and Al than total stems or leaves; roots contained no measurable Cl. In shoot segments, largest differences in concentrations due to fertilization occurred for K and S in upper stem segments, for Cl in lower stem and lower leaf segments, for Zn in lowest stem segment and stubble, for Mn in middle-to-lower stem segments and stubble, and for B in middle stem segment.

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EFFECTS OF TEMPERATURE ON PRIMARY GROWTH OF ALFALFA

Canadian Journal of Plant Science ◽

10.4141/cjps72-173 ◽

1972 ◽

Vol 52 (6) ◽

pp. 1007-1015 ◽

Cited By ~ 14

Author(s):

C. J. PEARSON ◽

L. A. HUNT

Keyword(s):

North America ◽

Medicago Sativa ◽

Low Temperatures ◽

Dry Matter ◽

Humid Zone ◽

Flower Production ◽

Primary Growth ◽

Whole Plant ◽

Medicago Sativa L ◽

Effects Of Temperature

Effects of temperature on the cumulative gain and distribution of dry matter are described for the primary growth of alfalfa (Medicago sativa L.) cults Vernal and Moapa at an irradiance (400–700 nm) of 25 nE cm−2 s−1. Whole plant dry weights and leaf areas increased curvilinearly with time. Weight and area increments were faster, root-top weight increments were higher, and canopies were more erect, at 15/10 C and 20/15 C day/night temperatures than under warmer conditions. In contrast, rates of leaf, node, and flower production were slower at low temperatures. Differences between low and high temperatures were similar to those recorded in the field between first and third harvests in the cool humid zone of North America.

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Seed Developmental Temperature Regulation of Thermotolerance in Lettuce

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.123.4.700 ◽

1998 ◽

Vol 123 (4) ◽

pp. 700-705 ◽

Cited By ~ 11

Author(s):

Yu Sung ◽

Daniel J. Cantliffe ◽

Russell T. Nagata

Keyword(s):

Temperature Limit ◽

Lettuce Seed ◽

Night Temperature ◽

Temperature Regimes ◽

Percent Germination ◽

Lettuce Seed Germination ◽

Growth Chambers ◽

Effects Of Temperature ◽

Dark Green ◽

High Soil Temperature

Lettuce (Lactuca sativa L.) seeds can fail to germinate at temperatures above 24 °C. The degree of thermotolerance is thought to be at least partly related to the environment under which the seed developed. In order to study the effects of temperature during seed development on subsequent germination, various lettuce genotypes were screened for their ability to germinate at temperatures ranging from 20 to 38 °C. Seeds of the selected genotypes `Dark Green Boston' and `Valmaine' (thermosensitive), `Floricos 83', `Everglades', and PI 251245 (thermotolerant) were produced at 20/10, 25/15, 30/20, and 35/25 °C day/night temperature regimes in plant growth chambers. Seeds were germinated on a thermogradient bar from 24 to 36 °C under 12 h light/dark cycles. As germination temperature increased, the number of seeds that failed to germinate increased. Above 27 °C, seeds matured at 20/10 or 25/15 °C exhibited a lower percent germination than seeds that matured at 30/20 or 35/25 °C. Seeds of `Dark Green Boston' and `Everglades' that matured at 30/20 °C exhibited improved thermotolerance over those that matured at lower temperatures. Seeds of `Valmaine' produced at 20/10 °C exhibited 40% germination at 30 °C, but seeds that matured at higher temperatures exhibited over 95% germination. Germination of `Valmaine' at temperatures above 30 °C was not affected by seed maturation temperature. The upper temperature limit for germination of lettuce seed could thus be modified by manipulating the temperature during seed production. The potential thermotolerance of seed thereby increased, wherein thermosensitive genotypes became thermotolerant and thermotolerant genotypes (e.g., PI251245) germinated fully at 36 °C. This information is useful for improving lettuce seed germination during periods of high soil temperature, and can be used to study the biology of thermotolerance in lettuce.

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The Effect of Foliar Boron Application on Seed Production of Alfalfa (Medicago sativa L.)

Biosis:Biological Systems ◽

10.37819/biosis.001.02.0056 ◽

2020 ◽

Vol 1 (2) ◽

pp. 60-64

Author(s):

Wurentuya ◽

Lingling Chen

Keyword(s):

Medicago Sativa ◽

Seed Production ◽

Seed Yield ◽

Foliar Application ◽

Pollen Viability ◽

Positive Effects ◽

Yield And Quality ◽

Alfalfa Seed ◽

Medicago Sativa L

Boron (B) is an essential micronutrient for plant reproductive growth and seed setting. A better understanding of the reasonable application rate of B could provide guidelines for improving seed yield and quality. In this study, we used five B concentrations (0, 400, 800, 1200, and 1600 mg B L-1) to study the effect of foliar application of B on seed yield and quality of alfalfa (Medicago sativa L.) in northern China. Our results indicated that foliar B application increased the pollen number, pollen viability, and dry weight and B concentration of alfalfa reproductive organs. The effect of B on alfalfa seed yield can be attributed to affecting the number of inflorescence and the seeds per pod. Foliar application with 800 mg B L-1 made quantitative and qualitative improvements in seed yield and quality of alfalfa. These results help to explain the positive effects of B on alfalfa seed production.

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