Relationship of indoleacetic acid and tryptophan to dormancy and preharvest sprouting of wheat

2003 ◽  
Vol 30 (9) ◽  
pp. 939 ◽  
Author(s):  
Shashi Ramaih ◽  
Mohammed Guedira ◽  
Gary M. Paulsen
Keyword(s):  
Triticum Aestivum ◽  
Abscisic Acid ◽  
Inhibitory Action ◽  
Indoleacetic Acid ◽  
Triticum Aestivum L ◽  
Preharvest Sprouting ◽  
Synthetic Auxins ◽  
Relationship Of ◽  
Related Compounds

Preharvest sprouting of wheat (Triticum aestivum L.) involves several plant hormones, but a role for indoleacetic acid (IAA) and its precursor, tryptophan, has not been demonstrated. Our objectives were to determine the roles of IAA, tryptophan, and related compounds in germination of cultivars that differed in susceptibility to preharvest sprouting. L-Tryptophan strongly inhibited germination of embryos excised from caryopses that were highly dormant at harvest but not of embryos from caryopses that had little innate dormancy. The embryos responded similarly to indoleacetaldehyde, IAA, and synthetic auxins, suggesting that tryptophan functioned as a precursor of IAA. Indoleacetaldehyde oxidase inhibitors alleviated the adverse effects of tryptophan and indoleacetaldehyde, and an auxin antagonist decreased the inhibitory action of tryptophan and IAA on embryos from dormant caryopses, further suggesting that IAA was involved. Changes in sensitivity to IAA during afterripening also supported a role for auxin in dormancy. Embryos from caryopses that were highly dormant at harvest gradually lost sensitivity to IAA during afterripening, whereas intact caryopses were insensitive to IAA. The results implicated IAA in dormancy of wheat caryopses and indicated that the auxin might complement the role of abscisic acid in germination. The importance of using dormant caryopses and arresting afterripening in investigations of seed dormancy was noted.

Inhibition of cambial activity in Abies balsamea by internal water stress: role of abscisic acid

1975 ◽  
Vol 53 (24) ◽  
pp. 3041-3050 ◽  
Author(s):  
C. H. A. Little
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Indoleacetic Acid ◽  
Stomatal Closure ◽  
Abies Balsamea ◽  
Cambial Activity ◽  
Inhibitory Effect ◽  
Internal Water ◽  
Endogenous Aba

In experiments with attached and detached shoots of balsam fir, Abies balsamea L., synthetic (±)abscisic acid (ABA) (1) reduced photosynthesis and transpiration by inducing stomatal closure, (2) inhibited indoleacetic acid (IAA) - induced cambial activity in photosynthesizing and non-photosynthesizing shoots, and (3) inhibited the basipetal movement of [14C]IAA. Neither gibberellic acid nor kinetin counteracted the inhibitory effect of (±)ABA on IAA-induced cambial activity. In addition it was demonstrated that increasing the internal water stress increased the level of endogenous ABA in the phloem–cambial region of bark peelings and decreased the basipetal movement of [14C]IAA through branch sections. On the basis of these findings it is proposed that internal water stress inhibits cambial activity, partly through increasing the level of ABA; the ABA acts to decrease the provision of carbohydrates and auxin that are required for cambial growth.

scholarly journals The genetics of late maturity alpha-amylase (LMA) in North American spring wheat (Triticum aestivum L.)

2021 ◽  
pp. 1-10
Author(s):  
Chang Liu ◽  
Rehana S. Parveen ◽  
Samuel R. Revolinski ◽  
Kimberly A. Garland Campbell ◽  
Michael O. Pumphrey ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Spring Wheat ◽  
North American ◽  
Genome Wide Association Study ◽  
Triticum Aestivum L ◽  
Preharvest Sprouting ◽  
Alpha Amylase ◽  
Reduced Height ◽  
Increased Risk ◽  
Late Maturity

Abstract Genetic susceptibility to late maturity alpha-amylase (LMA) in wheat (Triticum aestivum L.) results in increased alpha-amylase activity in mature grain when cool conditions occur during late grain maturation. Farmers are forced to sell wheat grain with elevated alpha-amylase at a discount because it has an increased risk of poor end-product quality. This problem can result from either LMA or preharvest sprouting, grain germination on the mother plant when rain occurs before harvest. Whereas preharvest sprouting is a well-understood problem, little is known about the risk LMA poses to North American wheat crops. To examine this, LMA susceptibility was characterized in a panel of 251 North American hard spring wheat lines, representing ten geographical areas. It appears that there is substantial LMA susceptibility in North American wheat since only 27% of the lines showed reproducible LMA resistance following cold-induction experiments. A preliminary genome-wide association study detected six significant marker-trait associations. LMA in North American wheat may result from genetic mechanisms similar to those previously observed in Australian and International Maize and Wheat Improvement Center (CIMMYT) germplasm since two of the detected QTLs, QLMA.wsu.7B and QLMA.wsu.6B, co-localized with previously reported loci. The Reduced height (Rht) loci also influenced LMA. Elevated alpha-amylase levels were significantly associated with the presence of both wild-type and tall height, rht-B1a and rht-D1a, loci in both cold-treated and untreated samples.

scholarly journals Pivotal role of bZIPs in amylose biosynthesis by genome survey and transcriptome analysis in wheat (Triticum aestivum L.) mutants

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Pankaj Kumar ◽  
Ankita Mishra ◽  
Himanshu Sharma ◽  
Dixit Sharma ◽  
Mohammed Saba Rahim ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Transcriptome Analysis ◽  
Triticum Aestivum L ◽  
Pivotal Role ◽  
Genome Survey

Cytokinins and abscisic acid in hardening winter wheat

1990 ◽  
Vol 68 (7) ◽  
pp. 1597-1601 ◽  
Author(s):  
John S. Taylor ◽  
Munjeet K. Bhalla ◽  
J. Mason Robertson ◽  
Lu J. Piening
Keyword(s):  
Triticum Aestivum ◽  
Abscisic Acid ◽  
Winter Wheat ◽  
Leaf Tissue ◽  
Triticum Aestivum L ◽  
Early Spring ◽  
Growth Chamber ◽  
Late Winter ◽  
Sequence Of Events ◽  
Freeze Dried

During overwintering in a northern climate, winter wheat goes through a hardening process, followed by dehardening in late winter – early spring. This sequence of events may be partially controlled by changes in endogenous hormone levels. Crowns and leaf tissue from field grown winter wheat (Triticum aestivum L. cv. Norstar) seeded at the beginning of September were collected and freeze-dried at monthly intervals during the winters of 1985–1986 and 1986–1987. Material was also sampled and freeze-dried from seedlings grown in a growth chamber under hardening conditions (21 °C for 2 weeks plus 3 °C for 6 weeks) or nonhardening conditions (3 weeks at 21 °C). The tissues were analysed for cytokinins and abscisic acid. Cytokinin levels, measured with the soybean hypocotyl section assay, declined from October onwards and then rose to a peak in late winter (January and February, winter 1986–1987; February and March, winter 1985–1986), subsequently declining again. Abscisic acid, quantitated as the methyl ester by gas chromatography with an electron capture detector, increased in level from October to December, then decreased to a relatively low level between January and March. Hardened seedlings from the growth chamber contained significantly higher abscisic acid levels and significantly lower cytokinin levels than did the nonhardened seedlings. Key words: abscisic acid, cytokinins, hardening, Triticum aestivum, winter wheat.

The Role of Leaf Epicuticular Wax in the Adaptation of Wheat ( Triticum aestivum L.) to High Temperatures and Moisture Deficit Conditions

Crop Science ◽  
2018 ◽  
Vol 58 (2) ◽  
pp. 679-689 ◽  
Author(s):  
Suheb Mohammed ◽  
Trevis D. Huggins ◽  
Francis Beecher ◽  
Chris Chick ◽  
Padma Sengodon ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
High Temperatures ◽  
Triticum Aestivum L ◽  
Epicuticular Wax ◽  
Moisture Deficit ◽  
Leaf Epicuticular Wax
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