Abstract
Senescence of shoot apices of Pisum sativum L. ‘Alaska’ as measured by cessation of stem elongation was delayed by removal of flowers. Analyses of total RNA, nitrogen, protein and inorganic phosphorus in shoot tips of deflowered and control (flower- and fruit-bearing) plants throughout ontogeny revealed that the levels of all these metabolites declined during senescence. Also throughout ontogeny shoot tips of control and deflowered plants were compared with respect to their ability to enzymically degrade RNA and to take up and incorporate P32-orthophosphate into RNA. The specific activity of ribonuclease increased as senescence progressed while the absolute activity appeared to decrease in correlation with a decrease in total nitrogen content. Compared with nonsenescing shoot tips, senescing shoot tips accumulated less P32 but exhibited an apparent enhancement of P32 incorporation into RNA, which was attributed to a reduction in the endogenous phosphorus pool causing a smaller dilution of the accumulated P32. It is concluded that decreases in the levels of RNA, protein and inorganic phosphorus and in the tran-spirational uptake of nutrients are factors correlated with senescence of the shoot apex.
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Claims 7
Claim · model-written summary
Removing flowers delayed senescence of pea shoot apices, measured as cessation of stem elongation, compared with control plants.
- Taxon
- Pisum sativum
Lathyrus oleraceuse0 - Organ / stage
- shoot apicese0
- Treatment
- removal of flowerse1
- Outcome
- cessation of stem elongatione1
- Direction
- delayede1
- Comparator
- control (flower- and fruit-bearing) plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e1“as measured by cessation of stem elongation was delayed by removal of flowers”
e2“Analyses of total RNA, nitrogen, protein and inorganic phosphorus in shoot tips of deflowered and control (flower- and fruit-bearing) plants throughout ontogeny revealed that the levels of all these metabolites declined during senescence”
Claim · model-written summary
The levels of total RNA, nitrogen, protein and inorganic phosphorus declined during senescence of pea shoot tips.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Organ / stage
- shoot tipse2
- Outcome
- levels of all these metabolitese2
- Direction
- declinede2
- Qualifier
- total RNA, nitrogen, protein and inorganic phosphoruse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e2“Analyses of total RNA, nitrogen, protein and inorganic phosphorus in shoot tips of deflowered and control (flower- and fruit-bearing) plants throughout ontogeny revealed that the levels of all these metabolites declined during senescence”
Claim · model-written summary
The specific activity of ribonuclease increased as senescence progressed in pea shoot apices.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Gene
- ribonucleasee3
- Outcome
- specific activity of ribonucleasee3
- Direction
- increasede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e3“The specific activity of ribonuclease increased as senescence progressed while the absolute activity appeared to decrease in correlation with a decrease in total nitrogen content”
Claim · model-written summary
The absolute ribonuclease activity appeared to decrease in correlation with a decrease in total nitrogen content in senescing pea shoot apices.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Gene
- ribonucleasee3
- Outcome
- absolute activitye3
- Direction
- decreasee3
- Qualifier
- in correlation with a decrease in total nitrogen contente3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e3“The specific activity of ribonuclease increased as senescence progressed while the absolute activity appeared to decrease in correlation with a decrease in total nitrogen content”
Claim · model-written summary
Senescing pea shoot tips accumulated less P32 than nonsenescing shoot tips.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Compound
- P32e4
- Outcome
- accumulatede4
- Direction
- lesse4
- Comparator
- nonsenescing shoot tipse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e4“Compared with nonsenescing shoot tips, senescing shoot tips accumulated less P32 but exhibited an apparent enhancement of P32 incorporation into RNA”
Claim · model-written summary
Senescing pea shoot tips showed an apparent enhancement of P32 incorporation into RNA compared with nonsenescing shoot tips.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Compound
- P32e4
- Outcome
- P32 incorporation into RNAe4
- Direction
- enhancemente4
- Comparator
- nonsenescing shoot tipse4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e4“Compared with nonsenescing shoot tips, senescing shoot tips accumulated less P32 but exhibited an apparent enhancement of P32 incorporation into RNA”
Claim · model-written summary
The enhanced P32 incorporation in senescing pea shoot tips is attributed to a reduced endogenous phosphorus pool causing smaller dilution of accumulated P32.
- Taxon
- Pisum sativumLathyrus oleraceuse0
- Outcome
- enhancement of P32 incorporation into RNAe4
- Qualifier
- attributed to a reduction in the endogenous phosphorus poole5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Senescence of shoot apices of Pisum sativum L.”
e4“Compared with nonsenescing shoot tips, senescing shoot tips accumulated less P32 but exhibited an apparent enhancement of P32 incorporation into RNA”
e5“which was attributed to a reduction in the endogenous phosphorus pool causing a smaller dilution of the accumulated P32”