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A novel morphological response of maize (Zea mays) adult roots to heterogeneous nitrate supply revealed by a split-root experiment

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Approximately 35–55% of total nitrogen (N) in maize plants is taken
up by the root at the reproductive stage. Little is known about how the
root of an adult plant responds to heterogeneous nutrient supply. In this
study, root morphological and physiological adaptations to nitrate-rich and
nitrate-poor patches and corresponding gene expression of ZmNrt2.1 and
ZmNrt2.2 of maize seedlings and adult plants were characterized. Local high
nitrate (LoHN) supply increased both lateral root length (LRL) and density
of the treated nodal roots of adult maize plants, but only increased LRL of
the treated primary roots of seedlings. LoHN also increased plant total N
acquisition but not N influx rate of the treated roots, when expressed as
per unit of root length. Furthermore, LoHN markedly increased specific root
length (m g−1) of the treated roots but significantly inhibited the growth of the
lateral roots outside of the nitrate-rich patches, suggesting a systemic carbon
saving strategy within a whole root system. Surprisingly, local low nitrate
(LoLN) supply stimulated nodal root growth of adult plants although LoLN
inhibited growth of primary roots of seedlings. LoLN inhibited the N influx
rate of the treated roots and did not change plant total N content. The gene
expression of ZmNrt2.1 and ZmNrt2.2 of the treated roots of seedlings and
adult plants was inhibited by LoHN but enhanced by LoLN. In conclusion,
maize adult roots responded to nitrate-rich and nitrate-poor patches by
adaptive morphological alterations and displayed carbon saving strategies in
response to heterogeneous nitrate supply.

Abbreviations – ARL, axial root length; DAT, days after treatment; DW, dry weight; HoHN, homogeneous high nitrate; HoLN,
homogeneous low nitrate; LoHN, local high nitrate; LoLN, local low nitrate; LRD, lateral root density; LRL, lateral root length;
LSD, least significant difference; Nconc., N concentration; Ncont., N content; Nrt, nitrate transporter gene; RT-PCR, reverse transcription-polymerase chain reaction; SRL, specific root length; TRL, total root length

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Ketersediaan

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Informasi Detail

Judul Seri

Physiologia Plantarum

No. Panggil

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Penerbit

Scandinavian : Scandinavian Plant Physiology Society., 2014

Deskripsi Fisik

Physiologia Plantarum 150: 133–144. 2014

Bahasa

English

ISBN/ISSN

0031-9317

Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

PERTANIAN.

Info Detail Spesifik

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Pernyataan Tanggungjawab

Agus

Versi lain/terkait

Lampiran Berkas

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