scholarly journals Interactions between Mild NaCl Stress and Red Light during Lettuce (Lactuca sativa L. cv Grand Rapids) Seed Germination

1985 ◽  
Vol 79 (1) ◽  
pp. 149-152 ◽  
Author(s):  
Keith N. Scorer ◽  
B. L. Epel ◽  
Yoav Waisel
Keyword(s):  
Seed Germination ◽  
Lactuca Sativa ◽  
Red Light ◽  
Nacl Stress ◽  
Lactuca Sativa L ◽  
Grand Rapids

The fine structure of the embryo of Lactuca sativa. II. Changes during germination

1968 ◽  
Vol 46 (11) ◽  
pp. 1447-1453 ◽  
Author(s):  
Lalit M. Srivastava ◽  
Ronald E. Paulson
Keyword(s):  
Fine Structure ◽  
Seed Germination ◽  
Lactuca Sativa ◽  
Root Tip ◽  
Membrane Systems ◽  
Lactuca Sativa L ◽  
Progressive Loss ◽  
Grand Rapids ◽  
Developmental Continuity ◽  
Embryo Cells

Changes in fine structure and reserve materials of the dormant embryos of Lactuca sativa L. var. Grand Rapids were studied during the first 4 days of germination. Activation of cells begins soon after the embryos are soaked and involves a progressive loss of reserve materials, an increased clarity of organelles and membrane systems, and development of structures either absent or present in a highly modified state in the dormant embryo. Cells of the hypocotyl just behind the root tip are first activated. Activation then progresses through the hypocotyl and acropetally in the cotyledons. These results are discussed in relation to physiology of seed germination. Plastids show several patterns of development, depending on the tissues in which they are localized. There is developmental continuity between the dissolution of protein bodies and formation of vacuoles.

Characterization of SAN 9789-Stimulated Lettuce (Lactuca sativa) Seed Germination

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 160-164 ◽  
Author(s):  
Karl-Olof Widell ◽  
Christer Sundqvist ◽  
Hemming I. Virgin
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Lactuca Sativa ◽  
Red Light ◽  
Inhibitory Effect ◽  
Lettuce Seeds ◽  
Grand Rapids ◽  
Minor Degree ◽  
A Minor

Dark germination of light-requiring lettuce seeds (Lactuca sativaL. ‘Grand Rapids’) was stimulated by SAN 9789 [4-chloro-5-(methylamino-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone] and to a minor degree by BASF 13761 [4-chloro-5-methoxy-2-phenyl-3(2H)-pyridazinone] and BASF 44521 [4-chloro-5-methoxy-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], but not by’ pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone], SAN 9785 [4-chloro-5-(dimethylamino)-2-phenyl-3 (2H)-pyridazinone], SAN 9774 [5-amino-4-chloro-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone], or SAN 6706 [4-chloro-5-(dimethylamino)-2-(α,α,α-trifluoro-m-tolyl)-3(2H)-pyridazinone]. SAN 9789 stimulation was inhibited by cis-4-cyclohexene-1,2-dicarboximide (CHDC), and abscisic acid (ABA) at 1 × 10-4M. Red light nullified the inhibitory effect of CHDC (1 × 10-4M) but not the inhibitory effect of ABA (1 × 10-4M) on SAN 9789 stimulated germination. Gibberellic acid (GA3) and kinetin (6-furfurylaminopurine) increased the germination stimulatory effect of SAN 9789 in darkness. Temperatures above 25 C decreased the effect of SAN 9789, with a temperature of 35 C completely inhibiting germination. The inhibitory effect of CHDC was strongly decreased at temperatures below 20 C. SAN 9789-induced germination in darkness was always the same (25 to 26% units increase in germination) even though the red light-stimulated germination differed with the seed batch.

s-Triazine Effects on Seed Germination and Hypocotyl Hook Opening

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 461-464 ◽  
Author(s):  
C. G. P. Pillai ◽  
D. E. Davis
Keyword(s):  
Seed Germination ◽  
Gossypium Hirsutum ◽  
Lactuca Sativa ◽  
Red Light ◽  
Lettuce Seed ◽  
Grand Rapids

The effects of sevens-triazines on the opening of the hypocotyl hook of cotton (Gossypium hirsutumL. ‘DPL Smooth Leaf’) and the germination of lettuce seed (Lactuca sativaL. ‘Grand Rapids’) were investigated. Thes-triazines used were ametryne [2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine], atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], cyprazine [2-chloro-4-(cyclopropylamino)-6-(isopropylamino)-s-triazine], prometone [2,4-bis (isopropylamino)-6-methoxy-s-triazine], prometryne [2,4-bis (isopropylamino)-6-(methylthio)-s-triazine], propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine], and simazine [2-chloro-4,6-bis(ethylamino)-s-triazine]. All triazines except cyprazine stimulated germination of lettuce seed given 4 min of dim red light but none were stimulatory in the dark. Maximum stimulation occurred with 1 X 10-8to 1 X 10-12Ms-triazine. All triazines except atrazine and cyprazine stimulated the opening of cotton hypocotyl hooks given 2 hr of dim red light of thes-triazines tested. Prometryne and ametryne were the most stimulatory to hook opening in the light and the most inhibitory in the dark. Their effects paralleled those of kinetin.

An influence of water regime on the light response in germination of lettuce (Lactuca sativa var. Grand Rapids) seed

1971 ◽  
Vol 49 (8) ◽  
pp. 1359-1362 ◽  
Author(s):  
A. I-hsiung Hsiao ◽  
G. M. Simpson
Keyword(s):  
Lactuca Sativa ◽  
White Light ◽  
Water Regime ◽  
Red Light ◽  
Light Response ◽  
Lactuca Sativa L ◽  
Grand Rapids ◽  
Influence Of Water ◽  
Low Levels ◽  
Petri Plate

The germination response of Lactuca sativa L. var. Grand Rapids to different light qualities (red, blue, far-red, white) compared with darkness, is modified by the level of water in the petri plate used for germinating the seeds. Far-red light and blue light inhibit germination for 24 h in all levels of water studied whereas red inhibits in low levels and promotes in high levels. White light inhibits germination in low levels of water but not in high levels. At least part of the inhibiting effects of light on germination in low levels of water may be associated with induced lowering of water potential in the seeds.

Seed water content in relation to phytochrome-mediated germination of lettuce seeds (Lactuca sativa L. var. Grand Rapids)

1971 ◽  
Vol 49 (1) ◽  
pp. 111-115 ◽  
Author(s):  
A. I-Hsiung Hsiao ◽  
William Vidaver
Keyword(s):  
Water Content ◽  
Lactuca Sativa ◽  
Red Light ◽  
Second Stage ◽  
Lettuce Seeds ◽  
Lactuca Sativa L ◽  
Grand Rapids ◽  
Two Stages ◽  
Seed Water Content ◽  
Stimulation Of

It is possible to distinguish two stages in the influence of light on the germination of Lactuca sativa var. Grand Rapids (lettuce) seeds. The first stage, which is represented by the photoactivation or transformation of phytochrome, requires only a relatively low seed water content. Slightly higher seed water content is required for maximum far-red light repression, than for red light stimulation of germination. The second stage is indicated by the well-known situation in which previous red irradiations of the seeds can enhance germination but this takes place only with relatively high seed water content. Phototransformed phytochrome appears to persist and to be susceptible to photoreversal for at least 24 h after irradiation in the seeds with relatively low water content.

scholarly journals Preventing thermoinhibition in a thermosensitive lettuce genotype by seed imbibition at low temperature

2003 ◽  
Vol 60 (3) ◽  
pp. 477-480 ◽  
Author(s):  
Warley Marcos Nascimento
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
High Temperatures ◽  
Lactuca Sativa ◽  
Lettuce Seed ◽  
Temperature Dependent ◽  
Lettuce Seeds ◽  
Lactuca Sativa L ◽  
Lettuce Seed Germination ◽  
Dark Green

Lettuce (Lactuca sativa L.) seed germination is strongly temperature dependent and under high temperatures, germination of most of genotypes can be erratic or completely inhibited. Lettuce seeds of 'Dark Green Boston' (DGB) were incubated at temperatures ranging from 15° to 35°C at light and dark conditions. Other seeds were imbibed in dark at 20°; 25°; 30°; and 35°C for 8 and 16 hours and then transferred to 20 or 35°C, in dark. Seeds were also incubated at constant temperature of 20° and 35 °C, in the dark, as control. In another treatment, seeds were primed for 3 days at 15°C with constant light. DGB lettuce seeds required light to germinate adequately at temperatures above 25°C. Seeds incubated at 20°C had 97% germination, whereas seeds incubated at 35°C did not germinate. Seeds imbibed at 20°C for 8 and 16 hours had germination. At 35°C, seeds imbibed initially at 20°C for 8 and 16 hours, had 89 and 97% germination, respectively. Seeds imbibed at 25°C for 16 hours, germinated satisfactory at 35°C. High temperatures of imbibition led to no germination. Primed and non-primed seeds had 100% germination at 20°C. Primed seeds had 100% germination at 35°C, whereas non-primed seeds germinate only 4%. The first hours of imbibition are very critical for lettuce seed germination at high temperatures.

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