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Zhang Y.,Northwest University, China | Zhang Y.,Shanxi Agricultural University | Zhang Y.,Key Laboratory of Protected Horticultural Engineering in Northwest | Zhang L.,Northwest University, China | And 3 more authors.
Botanical Studies | Year: 2014

Background: Tomato is one of the most popular vegetables, and middle tolerance for salt stress. Spermidine (Spd) has an important role in plant defense mechanisms against abiotic stress; however, relatively few data are available regarding Spd in responses of tomato to saline-alkaline stress. The effect of 0.25 mmol/L Spd on some physiological parameters of two tomato cultivars grown in 75 mmol/L saline-alkaline solutions were studied. Two cultivars are cv. Jinpeng chaoguan which is a highly salt-tolerant ecotype and cv. Zhongza No. 9 which is more salt-sensitive ecotype. Results: Saline-alkaline stress upset nitrogen metabolism, induced the antioxidant enzyme activities, and accumulated much more reactive oxygen species (ROS) and osmoregulation substances in two tomato cultivars leaves. Under saline-alkaline stress condition, Spd-treated seedlings accumulated more osmoregulation substances and had greater activities of antioxidative enzymes. Exogenous Spd counteracted the stress-induced increase of contents of malondialdehyde and ammonium, glutamate dehydrogenase activity, and decreased in nitrate, nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, glutamate oxaloacetate transaminase, and glutamate pyruvate transaminase activities. Additionally, the effect of Spd was more significantly in salt-sensitive cultivar 'Zhongza No. 9'. Conclusions: Overall, exogenous spermidine can attenuate negative effects of saline-alkaline stress on tomato seedlings which effects may depend on the plant species, and even cultivars. © 2014 Zhang et al.; licensee Springer. Source

Zhang J.,Northwest Agriculture and Forestry University | Zhang J.,Key Laboratory of Protected Horticultural Engineering in Northwest | Zhao J.,Northwest Agriculture and Forestry University | Zhao J.,Key Laboratory of Protected Horticultural Engineering in Northwest | And 3 more authors.
Euphytica | Year: 2016

A diverse collection of 174 tomato plants was selected, including 123 accessions of cherry tomato (Solanum lycopersicum var. cerasiforme) and 51 accessions of heirloom cultivars (Solanum lycopersicum). Association-mapping for fruit nutritional and quality traits was conducted with 182 SSR using the mixed linear models. A total of 111 marker-trait associations (MTAs) (P < 0.005) were detected for ten measured traits. Most association loci were detected for fruit equatorial diameter, ascorbic acid and fruit weight, with 22, 22, 17 marker-trait associations, respectively. Co-localised quantitative trait loci (QTLs) and significant associations are compared, such as fw2.2, fw11.1, ED2a, brx2.1, PD3a, and PD9a, which validate this study. Moreover, we also compared previous genome-wide association studies and confirmed certain identified MTAs (e.g. CON30D-472, Z1707-10D) or genes, such as Solyc11g071840.1.1. Our results confirm some QTLs and highlight some new candidate chromosome regions with potential for further tomato fruit quality breeding. © 2015, Springer Science+Business Media Dordrecht. Source

Zh0061ng J.,Northwest University, China | Zh0061ng J.,Key Laboratory of Protected Horticultural Engineering in Northwest | Zhao J.,Northwest University, China | Zhao J.,Key Laboratory of Protected Horticultural Engineering in Northwest | And 9 more authors.
Frontiers in Plant Science | Year: 2015

Tomato volatiles, mainly derived from essential nutrients and health-promoting precursors, affect tomato flavor. Taste volatiles present a major challenge for flavor improvement and quality breeding. In this study, we performed genome-wide association studies (GWAS) to investigate potential chromosome regions associated with the tomato flavor volatiles. We observed significant variation (1200x) among the selected 28 most important volatiles in tomato based on their concentration and odor threshold importance across our sampled accessions. Using 174 tomato accessions, GWAS identified 125 significant associations (P < 0.005) among 182 SSR markers and 28 volatiles (27 volatiles with at least one significant association). Several significant associations were co-localized in previously identified quantitative trait loci (QTL). This result provides new potential candidate loci affecting the metabolism of several volatiles. © 2015 Zhang, Zhao, Xu, Liang, Chang, Yan, Li, Liang and Zou. Source

Cao K.,Northwest University, China | Cao K.,Key Laboratory of Protected Horticultural Engineering in Northwest | Cui L.,Northwest University, China | Cui L.,Key Laboratory of Protected Horticultural Engineering in Northwest | And 11 more authors.
Frontiers in Plant Science | Year: 2016

Compact and healthy young plants increase crop production and improve vegetable quality. Adverse climatic conditions and shading can cause young plants to become elongated and spindly. We investigated the effects of night break (NB) treatments on tomato plants using red light (RL) with an intensity of 20 µmol·m2·s−1. Tomato plants were subjected to NB treatments with different frequencies ranging from every 1, 2, 3, and 4 h, and plant growth, flowering, and yield were monitored. The results showed that with the increase of RL NB frequency, plant height decreased, stem diameter increased, and flower initiation delayed, the content of indole-3-acetic acid (IAA) and gibberellin 3 (GA3) in the leaf and stem declined. When the RL NB frequency was every 1 h, the heights of tomato plant decreased by 32.73% compared with the control, the diameter of tomato plants increased by 27.09% compared with the control, the number of leaves produced before flowering increased to 11, compared with 8 in the control, the contents of IAA and GA3 in the leaf decreased by 33.3 and 41.29% respectively compared with the control, the contents of IAA and GA3 in the stem decreased by 56.04 and 57.14% respectively compared with the control. After RL NB treatments, tomato plants were transplanted into a solar greenhouse to evaluate tomato yield. When tomato plants pre-treated with RL NB, per tomato fresh weight of the first spica increased with the increase of RL NB frequencies. These results indicate that more compact and healthier tomato plants could be gotten by RL NB treatments and improve tomato early yield. © 2016 Cao, Cui, Ye, Zhou, Bao, Zhao and Zou. Source

Hu L.,Northwest University, China | Hu L.,Key Laboratory of Protected Horticultural Engineering in Northwest | Xiang L.,Northwest University, China | Xiang L.,Key Laboratory of Protected Horticultural Engineering in Northwest | And 6 more authors.
Physiologia Plantarum | Year: 2016

Polyamines are important in protecting plants against various environmental stresses, including protection against photodamage to the photosynthetic apparatus. The molecular mechanism of this latter effect is not completely understood. Here, we have investigated the effects of salinity-alkalinity stress and spermidine (Spd) on tomato seedlings at both physiological and transcriptional levels. Salinity-alkalinity stress decreased leaf area, net photosynthetic rate, maximum net photosynthetic rate, light saturation point, apparent quantum efficiency, total chlorophyll, chlorophyll a and chlorophyll a:chlorophyll b relative to the control. The amount of D1 protein, an important component of photosystem II, was reduced compared with the control, as was the expression of psbA, which codes for D1. Expression of the chlorophyll biosynthesis gene porphobilinogen deaminase (PBGD) was reduced following salinity-alkalinity stress, whereas the expression of Chlase, which codes for chlorophyllase, was increased. These negative physiological effects of salinity-alkalinity stress were alleviated by exogenous Spd. Expression of PBGD and psbA were enhanced, whereas the expression of Chlase was reduced, when exogenous Spd was included in the stress treatment compared with when it was not. The protective effect of Spd on chlorophyll and D1 protein content during stress may maintain the photosynthetic apparatus, permitting continued photosynthesis and growth of tomato seedlings (Solanum lycopersicum cv. Jinpengchaoguan) under salinity-alkalinity stress. © 2016 Scandinavian Plant Physiology Society. Source

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