当前位置： SCI文献检索 > JOURNAL OF PLANT PHYSIOLOGY期刊下所有文献 > Nitrogen-source preference in blueberry (Vaccinium sp.): Enhanced shoot nitrogen assimilation in response to direct supply of nitrate.

Nitrogen-source preference in blueberry (Vaccinium sp.): Enhanced shoot nitrogen assimilation in response to direct supply of nitrate.

Abstract：

:Blueberry (Vaccinium sp.) is thought to display a preference for the ammonium (NH4+) form over the nitrate (NO3-) form of inorganic nitrogen (N). This N-source preference has been associated with a generally low capacity to assimilate the NO3- form of N, especially within the shoot tissues. Nitrate assimilation is mediated by nitrate reductase (NR), a rate limiting enzyme that converts NO3- to nitrite (NO2-). We investigated potential limitations of NO3- assimilation in two blueberry species, rabbiteye (Vaccinium ashei) and southern highbush (Vaccinium corymbosum) by supplying NO3- to the roots, leaf surface, or through the cut stem. Both species displayed relatively low but similar root uptake rates for both forms of inorganic N. Nitrate uptake through the roots transiently increased NR activity by up to 3.3-fold and root NR gene expression by up to 4-fold. However, supplying NO3- to the roots did not increase its transport in the xylem, nor did it increase NR activity in the leaves, indicating that the acquired N was largely assimilated or stored within the roots. Foliar application of NO3- increased leaf NR activity by up to 3.5-fold, but did not alter NO3- metabolism-related gene expression, suggesting that blueberries are capable of post translational regulation of NR activity in the shoots. Additionally, supplying NO3- to the cut ends of stems resulted in around a 5-fold increase in NR activity, a 10-fold increase in NR transcript accumulation, and up to a 195-fold increase in transcript accumulation of NITRITE REDUCTASE (NiR1) which codes for the enzyme catalyzing the conversion of NO2- to NH4+. These data indicate that blueberry shoots are capable of assimilating NO3- when it is directly supplied to these tissues. Together, these data suggest that limitations in the uptake and translocation of NO3- to the shoots may limit overall NO3- assimilation capacity in blueberry.

journal_name

J Plant Physiol

journal_title

Journal of plant physiology

authors

Alt DS,Doyle JW,Malladi A

doi

10.1016/j.jplph.2017.05.014

subject

Has Abstract

pub_date

2017-09-01 00:00:00

pages

79-87

eissn

0176-1617

issn

1618-1328

pii

S0176-1617(17)30134-7

journal_volume

216

pub_type

杂志文章

在线工具

Nitrogen-source preference in blueberry (Vaccinium sp.): Enhanced shoot nitrogen assimilation in response to direct supply of nitrate.