Abstract
P ratt , C harlotte , J ohn E inset , and M ohammad Z ahur . (N. Y. S. Agric. Expt. Sta., Geneva.) Radiation damage in apple shoot apices. Amer. Jour. Bot. 46(7): 537–544. Illus. 1959.—Pattern of shoot growth and anatomy of the shoot apex of ‘Golden Delicious’ apple trees on ‘East Malling IX’ rootstock are compared in normal trees and those growing under chronic gamma irradiation (average doses of 17–48 r per 20‐hr. day) at Brookhaven National Laboratory. Bud damage in 6 varieties of apple trees is compared. Irradiated ‘Golden Delicious’ formed lateral buds on the current year's shoot, but the following year these buds grew into spurs which failed to form a terminal bud (“budless” spurs) and enlarged to form “club tips” and “swollen spurs” in this and subsequent years. Cells with thick walls and lightly stained cytoplasm occurred in shoot apices of irradiated lateral buds in mid‐June. The first tunica layer was more resistant to radiation than the inner tunica layers and the corpus; pith rib meristem was still more resistant. Inflorescence and floral meristems were rarely found, but once formed, continued development. One‐year‐old budless spurs had a few leaves but neither an organized apical meristem nor leaf primordia. Surface of the apex was often folded. Periderm and, later, deep‐lying wound cambium developed. Expansion of pith, vascular tissue, cortex, wound cambium and periderm caused enlargement of club tips and swollen spurs. Many lateral buds from the gamma field which were propagated without irradiation in early August grew into long shoots with terminal buds. Scions removed from irradiation in November and inserted into normal trees showed lower survival and many of their shoots were budless. This suggests that the capacity for normal growth of a bud damaged by chronic irradiation is greater in mid‐summer than later in the year. With reference to percentage of budless shoots, ‘Delicious,’ ‘Golden Delicious’ and ‘McIntosh’ were more sensitive to an average dose of 24 r per day and lower doses than were ‘Cox,’ ‘Macoun’ and ‘Spy.’ Symptoms of radiation damage in apple buds during the first year were similar following acute or chronic irradiation. Degree of radiation damage, as expressed by death of apical meristems, was concluded to vary with stage of development of the bud, structure of the apical meristem, and genetic constitution.
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Claims 13
Claim · model-written summary
Irradiated Golden Delicious lateral buds grew into budless spurs and swollen tips the next year.
- Taxon
- apple trees
Malus domesticae1 - Material
- ‘Golden Delicious’e0
- Organ / stage
- lateral budse0
- Outcome
- spurs which failed to form a terminal bude0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Irradiated ‘Golden Delicious’ formed lateral buds on the current year's shoot, but the following year these buds grew into spurs which failed to form a terminal bud (“budless” spurs) and enlarged to form “club tips” and “swollen spurs””
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Irradiated lateral bud apices had thick-walled, lightly stained cells in mid-June.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- shoot apicese0
- Outcome
- Cells with thick walls and lightly stained cytoplasme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cells with thick walls and lightly stained cytoplasm occurred in shoot apices of irradiated lateral buds in mid‐June.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Outer tunica was more radiation resistant than inner layers and corpus; pith rib meristem was more resistant still.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- first tunica layere0
- Outcome
- resistant to radiatione0
- Direction
- more resistante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The first tunica layer was more resistant to radiation than the inner tunica layers and the corpus; pith rib meristem was still more resistant.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Inflorescence and floral meristems were rare but developed after forming.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- floral meristemse0
- Outcome
- Inflorescence and floral meristemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inflorescence and floral meristems were rarely found, but once formed, continued development.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
One-year budless spurs lacked an organized apical meristem and leaf primordia.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- budless spurse0
- Outcome
- neither an organized apical meristem nor leaf primordiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“One‐year‐old budless spurs had a few leaves but neither an organized apical meristem nor leaf primordia.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Budless spur apices often had folded surfaces.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- apexe0
- Outcome
- Surface of the apex was often foldede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Surface of the apex was often folded.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Periderm and subsequently deep wound cambium developed.
- Taxon
- apple treesMalus domesticae1
- Outcome
- Periderm and, later, deep‐lying wound cambium developede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Periderm and, later, deep‐lying wound cambium developed.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Expansion of several tissues enlarged club tips and swollen spurs.
- Taxon
- apple treesMalus domesticae1
- Outcome
- enlargement of club tips and swollen spurse0
- Qualifier
- Expansion of pith, vascular tissue, cortex, wound cambium and periderme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expansion of pith, vascular tissue, cortex, wound cambium and periderm caused enlargement of club tips and swollen spurs.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Many lateral buds removed from irradiation in August produced long shoots with terminal buds.
- Taxon
- apple treesMalus domesticae1
- Treatment
- propagated without irradiation in early Auguste0
- Outcome
- long shoots with terminal budse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Many lateral buds from the gamma field which were propagated without irradiation in early August grew into long shoots with terminal buds.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Scions removed in November had lower survival and many budless shoots.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- Scionse0
- Outcome
- survivale0
- Direction
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Scions removed from irradiation in November and inserted into normal trees showed lower survival and many of their shoots were budless.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Delicious, Golden Delicious and McIntosh were more radiation sensitive than Cox, Macoun and Spy.
- Taxon
- apple treesMalus domesticae1
- Material
- ‘Delicious,’ ‘Golden Delicious’ and ‘McIntosh’e0
- Outcome
- sensitivee0
- Direction
- more sensitivee0
- Value
- 24 r per daye0
- Comparator
- ‘Cox,’ ‘Macoun’ and ‘Spye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“‘Delicious,’ ‘Golden Delicious’ and ‘McIntosh’ were more sensitive to an average dose of 24 r per day and lower doses than were ‘Cox,’ ‘Macoun’ and ‘Spy.’”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Acute and chronic irradiation produced similar first-year bud symptoms.
- Taxon
- apple treesMalus domesticae1
- Outcome
- Symptoms of radiation damage in apple budse0
- Comparator
- acute or chronic irradiatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Symptoms of radiation damage in apple buds during the first year were similar following acute or chronic irradiation.”
e1“‘Golden Delicious’ apple trees”
Claim · model-written summary
Apical meristem death varied with developmental stage, meristem structure and genotype.
- Taxon
- apple treesMalus domesticae1
- Organ / stage
- stage of development of the bude0
- Outcome
- death of apical meristemse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Degree of radiation damage, as expressed by death of apical meristems, was concluded to vary with stage of development of the bud, structure of the apical meristem, and genetic constitution.”
e1“‘Golden Delicious’ apple trees”