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Study Examines Iron Deficiency in Kentucky Bluegrass
March 1, 2009 By: Golfdom Staff TurfGrass TrendsInformation proves valuable for geneticists seeking development of new cultivars
Physiological response
As expected, all cultivars showed much greater chlorosis at 1 than at 10 μM Fe. However, the Baron cultivar developed more severe chlorosis than Award, Rugby II and Limousine at both the high and low levels of Fe (Figure 1). In addition, Baron re-greened after day nine at the higher level of Fe while all other cultivars' chlorosis worsened as the treatment progressed.
 Figure 1. Visual chlorosis ratings and phytosiderophore production for four Kentucky bluegrass cultivars relative to the most chlorotic cultivar (Baron). For comparing among cultivars for chlorosis or phytosiderophore, columns with the same letter are not significantly different. |
For all four cultivars grown at the low level of Fe, chlorosis increased during the course of the treatment.
Expectedly, the low Fe treatments had 25 percent less shoot Fe concentration than the adequate Fe treatments (Figure 2). Similarly, the low Fe treatments had 67 percent less root Fe concentration than the adequate Fe treatments. The Fe deficiency at the 1 μM Fe level resulted in slightly less average shoot yield but a 7 percent greater root yield than the 10 μM Fe treatment.
 Figure 2. Phytosiderophore production, shoot yield, root yield, shoot iron concentration and root iron concentration of four Kentucky bluegrass cultivars grown with low (1 micrometer) hydroponic solution iron concentration, relative to the adequate (10 micrometer) level. Asterisk indicates a significant difference (p<0.05) between 1 and 10 micrometer levels for the given parameter. |
All four cultivars produced significant amounts of phytosiderophore in response to Fe deficiency at the low compared to the high level of Fe. Baron, however, surprisingly produced 12 percent more phytosiderophore than the other cultivars.
Physiology implications
Based on previous work with other species (Hansen et al., 2006), we expected susceptibility to Fe-deficiency chlorosis in KBG to be related to a cultivar's inability to produce adequate phytosiderophore.
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The unexpected result of our experiment was, however, that the cultivar developing the most chlorosis during the course of the treatment (Baron) also produced the most phytosiderophore and at a significantly higher level than the other cultivars. This finding implies that Fe-deficiency susceptibility in KBG may be related to inefficient uptake, transport or utilization physiology rather than phytosiderophore production and release.
This information is valuable for geneticists seeking the development of new cultivars that have high greenness scores in Fe-limiting soils.
Emily Buxton is an undergraduate majoring in plant biology at Brigham Young University in Provo, Utah. Bryan G. Hopkins, Ph.D., is associate professor of soil science; Von D. Jolley, Ph.D., is professor of environmental science; and Bruce L. Webb, M.S., is senior scientist in the Plant and Wildlife Sciences Department of Brigham Young.
REFERENCES
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