Claim · model-written summary
Sunflower plants receiving 6 mM nitrate accumulated more dry matter than urea-grown plants.
- Taxon
- Helianthus annuus
Helianthus annuuse0 - Material
- Hysun 21e0
- Treatment
- 6 mM nitratee1
- Outcome
- dry mattere1
- Direction
- moree1
- Comparator
- urea-grown plantse1
Not reportedGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleSettingValueQualifier
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Helianthus annuus L. cv. Hysun 21 grown on 6 mM urea in glasshouse culture”
e1“Plants that received 6 mM nitrate accumulated more dry matter than urea-grown plants”
Title
Distribution of Nitrogen during Growth of Sunflower (Helianthus annuus L.)
P. J. HOCKING; B. T. STEER Annals of Botany 1983. doi:10.1093/oxfordjournals.aob.a086530
Other claims from this paper (19)
- Observation Seed dry matter was transferred to seedlings with a net efficiency of 40 per cent.
- Observation Seed nitrogen was transferred to seedlings with a net efficiency of 86 per cent.
- Observation At flowering the stem held most of the plant's dry matter.
- Observation At flowering the leaves held most of the plant's nitrogen.
- Observation About 35 per cent of the plant's nitrogen accumulated after three-row anthesis.
- Observation The amount of protein in vegetative parts, especially leaves, declined after flowering.
- Observation Concentrations of free amino compounds decreased during growth.
- Observation Mature seeds held 38 per cent of the total plant dry weight.
- Observation Mature seeds held 68 per cent of the total plant nitrogen.
- Observation Seeds acquired 33 per cent of their dry matter and nitrogen by redistribution from above-ground plant parts.
- Observation Over 50 per cent of the nitrogen in the stem and leaves was redistributed.
- Intervention effect Seeds from nitrate-grown plants were heavier (58 mg) than those of urea-grown plants (46 mg).
- Intervention effect Seeds from nitrate-grown plants had a greater oil percentage (50) than those from urea-grown plants (41).
- Intervention effect The amount of nitrogen per seed was the same for nitrate-grown and urea-grown plants.
- Observation Little or no urea was detected in xylem sap of plants supplied with 5 mM urea, but it was detected at 25 mM.
- Observation Concentrations of urea and amino compounds in the xylem sap decreased up the stem.
- Observation In nitrate-supplied plants most xylem sap nitrogen was NO2−, suggesting little nitrate reduction in roots.
- Observation Plants grown on 6 mM nitrate and changed to high urea-nitrogen for 14 days still had high nitrate, while little nitrate remained in plants receiving low urea.
- Mechanism The authors conclude that urea applied in irrigation water to field-grown sunflower is subsequently taken up as nitrate because of rapid soil nitrogen transformations.