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THE EFFECTS OF WATER STRESS ON NITROGEN‐FIXING ROOT NODULES
Author(s) -
SPRENT JANET I.
Publication year - 1972
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1972.tb01270.x
Subject(s) - vicia faba , nitrogen fixation , nitrogen , irrigation , water stress , agronomy , root nodule , shoot , chemistry , horticulture , field capacity , botany , biology , organic chemistry
S ummary Water stress reduced nitrogen fixation of soybean plants grown in pots of sand. Provided that the nodules retained some activity, recovery on watering was normally complete in an hour. Using tritiated water ( 3 HOH) it was confirmed that water could be withdrawn by nodules en route from the root to the shoot system. A field trial with Vicia faba showed a high degree of correlation between soil‐water content and nitrogen‐fixing activity. Slow natural drying over a 6‐week period resulted in progressive reduction of activity, which was restored by irrigation. Maximum nitrogen fixation occurred at about field capacity; above this, activity was reduced due to water logging. Under the conditions of the experiment, water supply was the major environmental factor affecting nitrogen fixation. It is suggested that water stress affects nodule activity directly, but that this effect may be aggravated by reduced supplies of photosynthate from wilted leaves.