Nitrogen dynamics and the physiological basis of stay-green in sorghum

Borrell, AK and Hammer, GL (2000) Nitrogen dynamics and the physiological basis of stay-green in sorghum. Crop Science, 40 5: 1295-1307. doi:10.2135/cropsci2000.4051295x

Author Borrell, AK
Hammer, GL
Title Nitrogen dynamics and the physiological basis of stay-green in sorghum
Journal name Crop Science   Check publisher's open access policy
ISSN 0011-183X
Publication date 2000-01-01
Year available 2000
Sub-type Article (original research)
DOI 10.2135/cropsci2000.4051295x
Open Access Status Not yet assessed
Volume 40
Issue 5
Start page 1295
End page 1307
Total pages 13
Place of publication MADISON
Language eng
Abstract Sorghum [Sorghum bicolor (L,) Moench] hybrids containing the stay-green trait retain more photosynthetically active leaves under drought than do hybrids that do not contain this trait. Since the Longevity and photosynthetic capacity of a leaf are related to its N status, it is important to clarify the role of N in extending leaf greenness in stay-green hybrids. Field studies were conducted in northeastern Australia to examine the effect of three water regimes and nine hybrids on N uptake and partitioning among organs. Nine hybrids varying in the B35 and KS19 sources of stay-green were grown under a fully irrigated control, post-flowering water deficit, and terminal water deficit. For hybrids grown under terminal water deficit, stay-green was viewed as a consequence of the balance between N demand by the grain and N supply during gain filling. On the demand side, grain numbers were 16% higher in the four stay-green than in the five senescent hybrids. On the supply side, age-related senescence provided an average of 34 and 42 kg N ha(-1) for stay-green and senescent hybrids, respectively. In addition, N uptake during grain filling averaged 116 and 82 kg ha(-1) in stay-green and senescent hybrids. Matching the N supply from these two sources with grain N demand found that the shortfall in N supply for grain filling in the stay-green and senescent hybrids averaged 32 and 41 kg N ha(-1) resulting in more accelerated leaf senescence in the senescent hybrids. Genotypic differences in delayed onset and reduced rate of leaf senescence were explained by differences in specific leaf nitrogen and N uptake during grain filling. Leaf nitrogen concentration at anthesis was correlated with onset (r = 0.751**, n = 27) and rate (r = -0.783**, n = 27) of leaf senescence ender terminal water deficit.
Keyword Agronomy
Radiation-use Efficiency
Photosynthetic Capacity
Genotypic Variation
Drought Tolerance
Interactive Water
Leaf Senescence
Ear Development
Tropical Maize
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
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Citation counts: TR Web of Science Citation Count  Cited 110 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 128 times in Scopus Article | Citations
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Created: Mon, 13 Aug 2007, 21:59:02 EST