摘要：
<jats:title>Abstract</jats:title><jats:p>Raising rice seedlings in flat trays has become the main method for mechanized transplanting of rice in China. However, seedling blocks raised by this method were easily cracked in practice, and this problem can be solved by padding a thin ramie fiber nonwoven film on the bottom surface of seedling tray. This study was conducted to determine the effects of this film on root-zone environment of rice seedlings. The results showed that on the 10<jats:sup>th</jats:sup> day after sowing, the soil inorganic nitrogen, especially nitrate nitrogen, content in the root-zone of the film treatment were considerably higher than in the no-film treatment, in contrast, the soil organic matter content was lower in the film treatment, and by the 20<jats:sup>th</jats:sup> day, the gap between treatments was enlarged. After applying the film, the Chao 1 index and Shannon index values for the soil bacterial community diversity decreased, and the rice seedlings were shorter, had higher root/shoot ratios, lower nitrate contents, and higher soluble sugar contents. We conclude that application of the ramie fiber nonwoven film resulted in substantial changes in the soil nutrient and bacterial community in root-zone in a short time, which significantly impacted the growth and development of rice seedlings.</jats:p>
作者机构：
[Wang, Chaoyun; Tan, Zhijian; Wang, Hongying] Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha, China;[Chen, Jing; Yi, Zhenxie] College of Agronomy, Hunan Agricultural University, Changsha, China;[Qi, Zhiyong] Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China;[Zhou, Wanlai] College of Agronomy, Hunan Agricultural University, Changsha, China<&wdkj&>Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha, China<&wdkj&>Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China
通讯机构：
[Chaoyun Wang] I;[Zhenxie Yi] C;Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha, China<&wdkj&>College of Agronomy, Hunan Agricultural University, Changsha, China
摘要：
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
摘要：
Rooting ability of rice seedling for mechanical transplanting has a large impact on grain yield. This study explored the relationship between endogenous soluble sugar content and rooting ability of rice seedlings. We placed 15-day-old rice seedlings in controlled environment cabinets with stable light and sampled after 0, 3, 6, 9, 12, and 24 hours of light to measure their soluble sugar content, nitrate content, starch content, soluble protein content and rooting ability. The soluble sugar content of the rice seedlings before rooting increased rapidly from 65.1 mg g-1 to 126.3 mg g-1 in the first 9 hours of light and then tended to stabilize; however, few significant changes in the other physiological indices were detected. With the light exposure time increasing from 3 hours to 12 hours, the rooting ability measured with fresh weight, dry weight, total length, and number of new roots increased by 91.7%, 120.0%, 60.6% and 30.3%, respectively. Rooting ability was related more closely to soluble sugar content than to nitrate-nitrogen content of rice seedlings before rooting and their correlation coefficients were 0.8582-0.8684 and 0.7045-0.7882, respectively. The stepwise regression analysis revealed that the soluble sugar content before rooting explained 73.6%-75.4% of the variance, and the nitrate-nitrogen content explained an additional 7.3%-14.2% of the variance in rooting ability, indicating that compared with nitrate-nitrogen content, soluble sugar content of rice seedlings before rooting was more dominant in affecting rooting ability. This study provides direct evidence of the relationship between the rooting ability and endogenous soluble sugar content of rice seedlings.
作者机构：
[Xie, Jun; Zhao, Jing; Lin, Jin-Hong; Ye, NH; Meng, Shuan; Xu, Zhi-Jun; Yi, Zhen-Xie; Ye, Neng-Hui] Hunan Agr Univ, Coll Agron, Southern Reg Collaborat Innovat Ctr Grain & Oil C, Changsha 410128, Hunan, Peoples R China.;[Peng, Jia-Shi] Hunan Univ Sci & Technol, Coll Life Sci, Key Lab Ecol Remediat & Safe Utilizat Heavy Met P, Xiangtan 411201, Peoples R China.;[Zhang, Guo-Bin] Shandong Agr Univ, Coll Agron, State Key Lab Crop Biol, Tai An 271018, Shandong, Peoples R China.;[Zhang, Jian-Hua] Hong Kong Baptist Univ, Dept Biol, Kowloon, Hong Kong 999077, Peoples R China.;[Zhang, Jian-Hua] Chinese Univ Hong Kong, Sch Life Sci, Shatin, Hong Kong 999077, Peoples R China.
摘要：
<jats:title>Abstract</jats:title>
<jats:sec>
<jats:title>Background</jats:title>
<jats:p>Proline (Pro) and γ-aminobutyric acid (GABA) play important roles in plant development and stress tolerance. However, the molecular components responsible for the transport of these molecules in rice remain largely unknown.</jats:p>
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<jats:title>Results</jats:title>
<jats:p>Here we identified OsProT1 and OsProT3 as functional transporters for Pro and GABA. Transient expression of eGFP-OsProTs in plant protoplasts revealed that both OsProT1 and OsProT3 are localized to the plasma membrane. Ectopic expression in a yeast mutant demonstrated that both OsProT1 and OsProT3 specifically mediate transport of Pro and GABA with affinity for Pro in the low affinity range. qRT-PCR analyses suggested that <jats:italic>OsProT1</jats:italic> was preferentially expressed in leaf sheathes during vegetative growth, while <jats:italic>OsProT3</jats:italic> exhibited relatively high expression levels in several tissues, including nodes, panicles and roots. Interestingly, both <jats:italic>OsProT1</jats:italic> and <jats:italic>OsProT3</jats:italic> were induced by cadmium stress in rice shoots.</jats:p>
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<jats:title>Conclusions</jats:title>
<jats:p>Our results suggested that plasma membrane-localized OsProT1 and OsProT3 efficiently transport Pro and GABA when ectopically expressed in yeast and appear to be involved in various physiological processes, including adaption to cadmium stress in rice plants.</jats:p>
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