关键词：
Auxin transport inhibitor;Indole-3-acetic acid;Peanut;Pegging stage
摘要：
This study was conducted to determine the effects of indole-3-acetic acid (IAA) and auxin polar transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) on the growth, photosynthetic characteristics of leaves and IAA contents in different parts of peanut cv. Zhonghua 4 at pegging stage. It was found that spraying IAA resulted in an increase in IAA contents of different parts, the photosynthetic rate, and the growth of stem, peg and flower at pegging stage. Treatment with TIBA increased the first branch length and branch number per plant by 6.83% and 15.34%, while the stem height, peg length, flower number and peg number per plant were significantly inhibited by 25.08%, 29.52%, 33.18% and 30.14%. The average weights of single pod and the yield per pot with auxin and TIBA treatments were distinctly higher than the control. Pegging rate and net photosynthesis rate were enhanced by 4.56% and 12.67%, respectively, but intercellular CO2 concentration (Ci) was decreased than the control by 8.06% under 10 mu MTIBA treatment. The IAA contents of stems and leaves treated with 10 mu M TIBA were also significantly increased. These results suggest that auxin, along with its transport and distribution, control the growth of peanut at pegging stage, which may contribute to higher yield through enhanced pod development. (C) 2013 Elsevier B.V. All rights reserved.
关键词：
Chlorocholine chloride;Drought stress;Solanum tuberosum L.
摘要：
The potted potatoes were grown in a greenhouse. During early tuber bulking stage, plants were exposed to full irrigation (FI), FI and chlorocholine chloride (FI+CCC), deficit irrigation (DI), and (DI+CCC) treatments for 18 days. The physiological responses relating to stomata and senescence parameters for late season potato were investigated. The results showed that the parameters of light response curve in FI+CCC and DI+CCC treated leaves on 18 days after treatment (DAT) were significantly improved those of in FI and DI controls, respectively. The net photosynthetic rate (A), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) in FI+CCC and DI+CCC-treated leaves for late season potato were superior to those of FI and DI controls, respectively. Analysis of the pooled data on 18 DAT showed that Gs was logarithmically correlated with A; photosynthetic water use efficiency (PWUE), viz. A/Gs, increased linearly with decreasing Gs. Spraying 2.0 g l(-1) CCC resulted in an 35.0% and 124.0% increase in the content of CTK/ABA in FI and DI in potato leaves, respectively. The leaf water potential (Psi l), root water potential (Psi r) and relative water content (RWC) in FI+CCC and DI+CCC were significantly improved compared to those of FI and DI controls, respectively. Compared with FI and DI, FI+CCC and DI+CCC treatments saved 15.9% and 11.5% water and increased crop water use efficiency (WUE) by 34.3% and 27.9% during the experimental period, respectively. The relative electrical conductivity and the content of malondialdehyde (MDA) in FI+CCC and DI+CCC were less than those of FI and DI controls, respectively. The root vitality in FI+CCC, DI+CCC treatments were 39.5% and 54.4% higher than those of FI and DI treatments, respectively. Collectively, the results of this research identify that optimized application of CCC resulted in significant improvement in PWUE and WUE for late season potato under soil well-irrigated and drought stressed condition.
摘要：
Abscisic acid (ABA) regulates many aspects of plant development, including seed dormancy and germination, root growth and stomatal closure. Plant SKP1 proteins are subunits of the SCF complex E3 ligases, which regulate several phytohormone signalling pathways through protein degradation. However, little is known about SKP1 proteins participating in ABA signalling. Here, we report that the overexpression of Triticum aestivum SKP1-like 1 (TSK1) in Arabidopsis thaliana (Arabidopsis) resulted in delayed seed germination and hypersensitivity to ABA. The opening of stomatal guard cells and the transcription of several ABA-responsive genes were affected in transgenic plants. In contrast, Arabidopsis skp1-like 1 (ask1)/ask1 ASK2/ask2 seedlings exhibited reduced ABA sensitivity. Furthermore, the transcription of ASK1 and ASK2 was down-regulated in abi1-1 and abi5-1 mutants compared with that in wild type. ASK1 or ASK2 overexpression could rescue or partially rescue the ABA insensitivity of abi5-1 mutants, respectively. Our work demonstrates that SKP1 is involved in ABA signalling and that SKP1-like genes may positively regulate ABA signalling by SCF-mediated protein degradation.
摘要：
Plants must effectively defend against biotic and abiotic stresses to survive in nature. However, this defense is costly and is often accompanied by significant growth inhibition. How plants coordinate the fluctuating growth-defense dynamics is not well understood and remains a fundamental question. Jasmonate (JA) and gibberellic acid (GA) are important plant hormones that mediate defense and growth, respectively. Binding of bioactive JA or GA ligands to cognate receptors leads to proteasome-dependent degradation of specific transcriptional repressors (the JAZ or DELLA family of proteins), which, at the resting state, represses cognate transcription factors involved in defense (e.g., MYCs) or growth [e.g. phytochrome interacting factors (PIFs)]. In this study, we found that the coi1 JA receptor mutants of rice (a domesticated monocot crop) and Arabidopsis (a model dicot plant) both exhibit hallmark phenotypes of GA-hypersensitive mutants. JA delays GA-mediated DELLA protein degradation, and the della mutant is less sensitive to JA for growth inhibition. Overexpression of a selected group of JAZ repressors in Arabidopsis plants partially phenocopies GA-associated phenotypes of the coi1 mutant, and JAZ9 inhibits RGA (a DELLA protein) interaction with transcription factor PIF3. Importantly, the pif quadruple (pifq) mutant no longer responds to JA-induced growth inhibition, and overexpression of PIF3 could partially overcome JA-induced growth inhibition. Thus, a molecular cascade involving the COI1-JAZ-DELLA-PIF signaling module, by which angiosperm plants prioritize JA-mediated defense over growth, has been elucidated.
关键词：
Inhibitor of ABA and GA biosynthesis;Lactuca sativa 'Jianye Xianfeng No. 1';Nitrate;PTIO;Phytohormone;Thermoinhibition of seed germination
摘要：
Germination of lettuce seeds has obvious thermoinhibition, but the mechanism for thermoinhibition of seed germination is poorly understood. Here, we investigated the interactions of nitrate, abscisic acid (ABA) and gibberellin on seed germination at high temperatures to understand further the mechanism for thermoinhibition of seed germination. Our results showed that lettuce (Lactuca sativa L. 'Jianye Xianfeng No. 1') seeds exhibited notable thermoinhibiton of germination at a parts per thousand yen17A degrees C in darkness, and at a parts per thousand yen23A degrees C in light, but the thermoinhibited seeds did not exhibit secondary dormancy. Thermoinhibition of seed germination at 23 or 25A degrees C in light was notably decreased by 5 and 10 mM nitrate, and the stimulatory effects were markedly prevented by nitric oxide (NO) scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. The sensitivity of seed germination to exogenous ABA increased with increasing temperature. Thermoinhibition of seed germination was markedly decreased by fluridone (an inhibitor of ABA biosynthesis) and GA(3), and was increased by diniconazole (an inhibitor of the ABA-catabolizing enzyme ABA 8'-hydroxylase) and paclobutrazol (an inhibitor of GA biosynthetic pathway). The effect of fluridone in decreasing thermoinhibition of seed germination was obviously antagonized by paclobutrazol, and that of GA(3) was notably added to by fluridone, and that of nitrate was antagonized by paclobutrazol, diniconazole and ABA and was added to by GA(3) and fluridone. Our data show that thermoinhibition of lettuce seed germination is decreased by nitrate in a NO-dependent manner, which is antagonized by ABA, diniconazole and paclobutrazol and added by fluridone.
摘要：
The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characterize the mesophyllous cells of rice sheath and how it may attribute to the rice yield. In this paper, super hybrid rice Liangyoupeijiu, its parents Wumang 9311 and Peiai 64S, and hybrid rice Shanyou 63 were studied as the experimental materials, and the characteristics of the mesophyllous cells of rice sheaths were examined by microscopic and super-microscopic observation as well as chlorophyll absorption spectrums. The results showed that rice sheath was rich in the intact mesophyllous cells full of chloroplasts, grana and thylakoids, which were much the same as those of rice blade. The absorption spectrum curves of the Chl. a and b of the sheaths were similar to those of the blades. The stomatal density in the outer epidermises of the sheaths was comparable to those in the up- and down-epidermises of the blades. The significant tests proved that the amount of chloroplast per mesophyllous cell of the sheaths was almost the same as those of the blades, and the mesophyllous cells in the sheaths were also rich in chlorophylls. The chlorophyll content of rice sheath reached about 50% of the chlorophyll content of rice blade, and the Pn of the sheath/the blade ranged from 13.60 to 34.57%. Therefore, rice sheath was also full of the intact photosynthetic apparatus similar to those in rice blade, and had capabilities of photosynthesis. The statistical analysis revealed that the physiological senescence of the photosynthetic apparatus in both the sheath and the blade of Liangyoupeijiu was significantly slower than those of the other varieties at the late stages. The profuse grain-filling stage was an inflexion point of the physiological senescence of the chloroplasts and the chlorophylls of both the blades and the sheaths.
通讯机构：
[Ma, Zhengqiang] N;Nanjing Agr Univ, Crop Genom & Bioinformat Ctr, Nanjing 210095, Jiangsu, Peoples R China.
关键词：
Defence signalling;disease resistance;jacalin-related lectin;jasmonic acid;salicylic acid;wheat (Triticum aestivum L.)
摘要：
Jacalin-related lectins (JRLs) are a subgroup of proteins with one or more jacalin-like lectin domains. Although JRLs are often associated with biotic or abiotic stimuli, their biological functions in plants, as well as their relationships to plant disease resistance, are poorly understood. A mannose-specific JRL (mJRL)-like gene (TaJRLL1) that is mainly expressed in stem and spike and encodes a protein with two jacalin-like lectin domains was identified in wheat. Pathogen infection and phytohormone treatments induced its expression; while application of the salicylic acid (SA) biosynthesis inhibitor paclobutrazol and the jasmonic acid (JA) biosynthesis inhibitor diethyldithiocarbamic acid, respectively, substantially inhibited its expression. Attenuating TaJRLL1 through virus-induced gene silencing increased susceptibility to the facultative fungal pathogen Fusarium graminearum and the biotrophic fungal pathogen Blumeria graminis. Arabidopsis thaliana transformed with TaJRLL1 displayed increased resistance to F. graminearum and Botrytis cinerea. JA and SA levels in transgenic Arabidopsis increased significantly. A loss or increase of disease resistance due to an alteration in TaJRLL1 function was correlated with attenuation or enhancement of the SA- and JA-dependent defence signalling pathways. These results suggest that TaJRLL1 could be a component of the SA- and JA-dependent defence signalling pathways.
摘要：
To develop an efficient green extraction approach for recovery of bioactive compounds from natural plants, we examined the potential of pressurized liquid extraction (PLE) of ginger (Zingiber officinale Roscoe) with bioethanol/water as solvents. The advantages of PLE over other extraction approaches, in addition to reduced time/solvent cost, the extract of PLE showed a distinct constituent profile from that of Soxhlet extraction, with significantly improved recovery of diarylheptanoids, etc. Among the pure solvents tested for PLE, bioethanol yield the highest efficiency for recovering most constituents of gingerol-related compounds: while for a broad concentration spectrum of ethanol aqueous solutions, 70% ethanol gave the best performance in terms of yield of total extract, complete constituent profile and recovery of most gingerol-related components. PLE with 70% bioethanol operated at 1500 psi and 100 degrees C for 20 min (static extraction time: 5 min) is recommended as optimized extraction conditions, achieving 106.8%, 109.3% and 108.0% yield of [6]-, [8]- and [10]-gingerol relative to the yield of corresponding constituent obtained by 8 h Soxhlet extraction (absolute ethanol as extraction solvent). (C) 2011 Elsevier B.V. All rights reserved.
摘要：
Plant pathogenic fungi produce mycotoxins which may lead host plants to produce disease symptoms and may have a significant positive role in the course of disease development. The putative Phytophthora infestans toxins were prepared by culturing in liquid medium (60 g rye and 10% tomato juice L-1) for 1 mon at 17°C, filtering through four layers of cheesecloth and being precipitated by ammonium sulfate. The resulted putative toxin solutions were used to study the effects on 3 potato varieties (both leaf and tuber tissues). The results show that potato leaves and tubers exhibit symptoms similar to the late blight resulted from P. infestans infection. Potato varieties reacting differentially to both the toxin dilutions and toxins produced by different P. infestans isolates suggested the presence of toxin-mediated specificities between potato and P. infestans. Potato leaf and tuber tissues have different and contrary reactions to the toxin. Toxin-mediated specificities are likely present between potato and P. infestans.
摘要：
In southern China, potatoes (Solanum tuberosum L.) are grown in the late season and the crops are often subjected to low temperature stress particularly during the tuber bulking stage. Exogenous chlorocholine chloride (CCC) treatment has been found to improve crop performance under suboptimal growth conditions; however, the physiological mechanisms underlying the beneficial effects have not been fully understood. The objective of this study was to investigate the effects of CCC treatment on mineral nutrition, antioxidant enzyme system, and tuber yield of potato (cv. Zhongshu 3) under field conditions. The plants were foliar sprayed twice with 1.5, 2.0 and 2.5 g l(-1) CCC at 24 and 28 clays after emergence (DAE), respectively; and plants without CCC treatment were serviced as control. Leaf samples were collected on 56 DAE for determination of mineral nutrition contents and antioxidant enzyme activity. Results showed that 1.5 and 2.0 g l(-1) CCC treatments significantly increased the contents of P, K, Ca, Mg, Fe, Mn, Zn and Cu in potato leaves. These treatments also increased superoxide dismutase (SOD), peroxidases (POD) and catalase (CAT) activities in the leaves. A positive linear relationship was found between SOD activity and the content of Fe + Mn + Zn + Cu. Tuber yield was significantly increased by CCC treatment. It is concluded that treatment with certain concentration of CCC (e.g. 1.5-2.0 g l(-1)) improves mineral nutrition and SOD, POD and CAT activities in potato leaves; which might have contributed to the higher tuber yield of the crop grown under suboptimal conditions. (c) 2010 Elsevier B.V. All rights reserved.
作者机构：
[Hao, Lin; Xia, Shitou; Li, Xin] Univ British Columbia, Michael Smith Labs, Vancouver, BC V6T 1Z4, Canada.;[Zhu, Zhaohai; Xia, Shitou; Zhang, Yuelin] Natl Inst Biol Sci, Beijing 102206, Peoples R China.;[Xia, Shitou; Xiao, Langtao] Hunan Agr Univ, Hunan Prov Key Lab Phytohormones & Growth & Dev, Changsha 410128, Hunan, Peoples R China.;[Li, Xin; Chen, Jin-Gui] Univ British Columbia, Dept Bot, Vancouver, BC V6T 1Z4, Canada.
通讯机构：
[Li, Xin] U;Univ British Columbia, Michael Smith Labs, Vancouver, BC V6T 1Z4, Canada.
摘要：
Systemic acquired resistance (SAR) is a plant immune response induced by local necrotizing pathogen infections. Expression of SAR in Arabidopsis (Arabidopsis thaliana) plants correlates with accumulation of salicylic acid (SA) and up-regulation of Pathogenesis-Related (PR) genes. SA is an essential and sufficient signal for SAR. In a genetic screen to search for negative regulators of PR gene expression and SAR, we found a new mutant that is hypersensitive to SA and exhibits enhanced induction of PR genes and resistance against the virulent oomycete Hyaloperonospora arabidopsidis Noco2. The enhanced pathogen resistance in the mutant is Nonexpressor of PR genes1 independent. The mutant gene was identified by map-based cloning, and it encodes a protein with high homology to Replication Factor C Subunit3 (RFC3) of yeast and other eukaryotes; thus, the mutant was named rfc3-1. rfc3-1 mutant plants are smaller than wild-type plants and have narrower leaves and petals. On the epidermis of true leaves, there are fewer cells in rfc3-1 compared with the wild type. Cell production rate is reduced in rfc3-1 mutant roots, indicating that the mutated RFC3 slows down cell proliferation. As Replication Factor C is involved in replication-coupled chromatin assembly, our data suggest that chromatin assembly and remodeling may play important roles in the negative control of PR gene expression and SAR.
