NMT歷*的今天

2012年9月16日，中科院南京土壤研究所施衛(wèi)明、張建華、許衛(wèi)鋒利用NMT在New Phytologist上發(fā)表了標(biāo)題為Abscisic acid accumulation modulates auxin transport in the root tip to enhance proton secretion for maintaining root growth under moderate water stress的研究成果。

期刊：New Phytologist

主題：脫落酸積累調(diào)節(jié)根尖中的生長(zhǎng)素運(yùn)輸以增強(qiáng)質(zhì)子分泌以在中度水脅迫下維持根生長(zhǎng)

標(biāo)題：Abscisic acid accumulation modulates auxin transport in the root tip to enhance proton secretion for maintaining root growth under moderate water stress

影響因子：6.645

檢測(cè)指標(biāo)：H⁺流速

檢測(cè)部位：擬南芥、水稻根尖（從根冠分界處50、100、200、300、400、500、600、700、800、900、1000、1200、1500、1800、2000、2500、3000、3500、4000和5000μm）

H⁺流實(shí)驗(yàn)處理方法：

15日齡水稻幼苗，5％PEG 8000或0.1 μM ABA處理24小時(shí)

H⁺流實(shí)驗(yàn)測(cè)試液成份：文獻(xiàn)無(wú)

推薦測(cè)試液：0.1mM CaCl20.3mM MES，pH6.0

作者：中科院南京土壤研究所施衛(wèi)明、張建華、許衛(wèi)鋒

英文摘要

Maintenance of root growth is essential for plant adaptation to soil drying. Here, we tested the hypothesis that auxin transport is involved in mediating ABA's modulation by activating proton secretion in the root tip to maintain root growth under moderate water stress.

Rice and Arabidopsis plants were raised under a hydroponic system and subjected to moderate water stress (−0.47 MPa) with polyethylene glycol (PEG). ABA accumulation, auxin transport and plasma membrane H+‐ATPase activity at the root tip were monitored in addition to the primary root elongation and root hair density.

We found that moderate water stress increases ABA accumulation and auxin transport in the root apex. Additionally, ABA modulation is involved in the regulation of auxin transport in the root tip. The transported auxin activates the plasma membrane H+‐ATPase to release more protons along the root tip in its adaption to moderate water stress. The proton secretion in the root tip is essential in maintaining or promoting primary root elongation and root hair development under moderate water stress.

These results suggest that ABA accumulation modulates auxin transport in the root tip, which enhances proton secretion for maintaining root growth under moderate water stress.

 中文摘要（谷歌機(jī)翻）

保持根系生長(zhǎng)對(duì)植物適應(yīng)土壤干燥至關(guān)重要。在這里，我們測(cè)試了生長(zhǎng)素轉(zhuǎn)運(yùn)通過激活根尖中的質(zhì)子分泌來介導(dǎo)ABA調(diào)節(jié)以在中等水分脅迫下維持根生長(zhǎng)的假設(shè)。

在水培系統(tǒng)下培養(yǎng)水稻和擬南芥植物，并用聚乙二醇（PEG）進(jìn)行適度的水分脅迫（-0.47MPa）。除了初生根伸長(zhǎng)和根毛密度之外，還監(jiān)測(cè)根尖處的ABA積累，生長(zhǎng)素轉(zhuǎn)運(yùn)和質(zhì)膜H+-ATP酶活性。

我們發(fā)現(xiàn)，適度的水分脅迫會(huì)增加根尖中ABA的積累和生長(zhǎng)素的轉(zhuǎn)運(yùn)。另外，ABA調(diào)節(jié)涉及根尖中生長(zhǎng)素運(yùn)輸?shù)恼{(diào)節(jié)。運(yùn)輸?shù)纳L(zhǎng)素激活質(zhì)膜H+-ATPase以沿著根尖釋放更多的質(zhì)子，以適應(yīng)中度水分脅迫。根尖中的質(zhì)子分泌對(duì)于在中度水分脅迫下維持或促進(jìn)初生根伸長(zhǎng)和根毛發(fā)育是*的。

這些結(jié)果表明，ABA積累調(diào)節(jié)根尖中的生長(zhǎng)素運(yùn)輸，這增強(qiáng)了質(zhì)子分泌，從而在中度水分脅迫下維持根生長(zhǎng)。

Fig. 1 Effects of moderate water stress or exogenous ABA treatment on H⁺ ?ux along the root tip of rice or Arabidopsis plants (0–5000 lm from the root cap junction). Fifteen-day-old rice or Arabidopsis plants were exposed to control conditions (●, control), moderate water stress (○,5%PEG 8000) or exogenous ABA (▼, 0.1 lM) for 24 h in hydroponics. The values are the means and SD of six replicates from two independent experiments.