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71.
菊芋耐性胁迫及种质保存研究进展 总被引:1,自引:0,他引:1
菊芋(Helianthus tuberous L.)属菊科向日葵属多年生草本植物,是重要的作物种质资源。国内外对菊芋已开展了生态、经济、能源及育种栽培等研究,近年来胁迫条件对菊芋的影响研究成为新的热点。菊芋是无性繁殖作物,目前对菊芋种质资源的保存主要采取田间圃位的形式,国外已经开展了试管苗保存和超低温保存等研究,而我国尚存在空白。本文着重从菊芋的胁迫耐性响应研究,包括干旱、盐碱及低温3个不同胁迫条件对田间性状、生理生化、蛋白、分子水平的研究,以及常规保存和离体保存等种质保存研究2个方面进行阐述,并指出目前存在的问题,为菊芋超低温保存和开发利用提供理论依据。 相似文献
72.
73.
In this study, it was found that the immobilized inulinase-producing cells of Pichia guilliermondii M-30 could produce 169.3 U/ml of inulinase activity while the free cells of the same yeast strain only produced 124.3 U/ml of inulinase activity within 48 h. When the immobilized inulinase-producing yeast cells were co-cultivated with the free cells of Rhodotorula mucilaginosa TJY15a, R. mucilaginosa TJY15a could accumulate 53.2% oil from inulin in its cells and cell dry weight reached 12.2 g/l. Under the similar conditions, R. mucilaginosa TJY15a could accumulate 55.4% (w/w) oil from the extract of Jerusalem artichoke tubers in its cells and cell dry weight reached 12.8 g/l within 48 h. When the co-cultures were grown in 2 l fermentor, R. mucilaginosa TJY15a could accumulate 56.6% (w/w) oil from the extract of Jerusalem artichoke tubers in its cells and cell dry weight reached 19.6 g/l within 48 h. Over 90.0% of the fatty acids from the yeast strain TJY15a grown in the extract of Jerusalem artichoke tubers was C16:0, C18:1 and C18:2, especially C18:1 (50.6%). 相似文献
74.
The levels of three essential minerals Ca, Fe and Mg and the extent of their availability were assessed in four commonly eaten
Caribbean tuber crops [dasheen (Xanthosoma spp.), Irish potato (Solanum tuberosum), sweet potato (Ipomoea batatas) and yellow yam (Dioscorea cayenensis)] in their processed and unprocessed states. Calcium was highest in cooked dasheen (5150±50 mg/kg) while Magnesium was highest
in uncooked Irish potato (3600±200 mg/kg). There was no significant loss of calcium from the food samples upon cooking. All
the uncooked food samples displayed higher levels minerals assessed compared to the cooked samples except for cooked Irish
potato that recorded the level of iron (182.25±8.75 mg/kg). Availability of these minerals in the cooked and uncooked tubers
crops upon digestion also showed a similar pattern. In conclusion, the consumption of these tuber crops in the Caribbean may
not be responsible for the reported cases of iron deficiency in the region. However, the␣availability of minerals from these
tuber crops when consumed with other foods (the usual practice in the Caribbean) needs further investigation. 相似文献
75.
Aims: Developing an innovative process for ethanol fermentation from Jerusalem artichoke tubers under very high gravity (VHG) conditions. Methods and Results: A consolidated bioprocessing (CBP) strategy that integrated inulinase production, saccharification of inulin contained in Jerusalem artichoke tubers and ethanol production from sugars released from inulin by the enzyme was developed with the inulinase‐producing yeast Kluyveromyces marxianus Y179 and fed‐batch operation. The impact of inoculum age, aeration, the supplementation of pectinase and nutrients on the ethanol fermentation performance of the CBP system was studied. Although inulinase activities increased with the extension of the seed incubation time, its contribution to ethanol production was negligible because vigorously growing yeast cells harvested earlier carried out ethanol fermentation more efficiently. Thus, the overnight incubation that has been practised in ethanol production from starch‐based feedstocks is recommended. Aeration facilitated the fermentation process, but compromised ethanol yield because of the negative Crabtree effect of the species, and increases the risk of contamination under industrial conditions. Therefore, nonaeration conditions are preferred for the CBP system. Pectinase supplementation reduced viscosity of the fermentation broth and improved ethanol production performance, particularly under high gravity conditions, but the enzyme cost should be carefully balanced. Medium optimization was performed, and ethanol concentration as high as 94·2 g l?1 was achieved when 0·15 g l?1 K2HPO4 was supplemented, which presents a significant progress in ethanol production from Jerusalem artichoke tubers. Conclusions: A CBP system using K. marxianus is suitable for efficient ethanol production from Jerusalem artichoke tubers under VHG conditions. Significance and Impact of the Study: Jerusalem artichoke tubers are an alternative to grain‐based feedstocks for ethanol production. The high ethanol concentration achieved using K. marxianus with the CBP system not only saves energy consumption for ethanol distillation, but also significantly reduces the amount of waste distillage discharged from the distillation system. 相似文献
76.
Janet LEAK‐GARCIA Jodie S. HOLT Seung‐Chul KIM Lisa MU José A. MEJÍ AS Norman C. ELLSTRAND 《植物分类学报:英文版》2013,51(3):295-307
The history of some invasive species is so complex that their origins can be difficult to determine. One example of such invasive species is the California invasive known as “wild artichoke thistle” (Cynara cardunculus var. sylvestris), found in natural and disturbed ecosystems. Wild artichoke thistle is a Mediterranean native and the progenitor of two domesticated horticultural taxa, artichoke and cardoon. Different hypotheses regarding the origins of California plants have included introductions by 19th century Italian immigrants and the de-domestication (evolutionary reversion to wild-type morphology) of feral (escaped, free-living) cultivars. Using microsatellite markers, we compared the genetic constitutions of 12 artichoke thistle populations in California with possible progenitor populations: 17 Spanish and Italian wild populations and eight different artichoke and cardoon cultivars. Each California population was compared with its putative progenitors using STRUCTURE analysis. Our results suggest that California's artichoke thistle populations are polyphyletic. Surprisingly, two-thirds of California's populations closely matched populations from the Iberian Peninsula. Three populations matched domesticated artichoke. One population appears to have wild and cultivar hybrid ancestry. Alleles specific to Italian populations were found at low frequencies in some California plants, suggesting that Italian wild plants may have been in California, but have left a trivial genetic legacy. Given that the de-domesticated plants in this study appear to be as invasive as the wild taxon, we conclude with a discussion of the role that ferality and de-domestication may have in plant invasions. 相似文献
77.
Alterations in the activity of ATPases, peroxidases and lipoxygenases were studied during early stages of post-harvest deterioration of cassava (Manihot esculenta Crantz cv. Oyolu) root tubers. The peak activities of Ca2+-ATPase, (Ca2++Mg2+)-ATPase, Na++K+-ATPase, Mg2+-ATPase and peroxidases were observed after the first 24 h and thereafter decreased. The activity of lipoxygenase was biphasic, probably depicting two distinct isoforms expressed during deterioration. The results indicate that ATPases and peroxidases have a role in the post-harvest deterioration of cassava tuber, but the participation of lipoxygenases seems unlikely. 相似文献
78.
Sirma Yegin 《Preparative biochemistry & biotechnology》2017,47(5):441-449
Statistical optimization of the factors affecting xylanase production by Aureobasidium pullulans NRRL Y-2311-1 on globe artichoke stem was performed for the first time. The optimization strategies used resulted in almost six-fold enhancement of xylanase production (66.48?U/ml). Biochemical and thermal characterization of the crude xylanase preparation was performed to elucidate its feasibility for different industrial applications. The optimum conditions for xylanase activity were pH 4.0 and 30–50°C. The enzyme was very stable over a wide pH range of 3.0–8.0. The thermal stability studies revealed an inactivation energy of 183?kJ/mol. Thermodynamic parameters (enthalpy, entropy, and Gibbs free energy) for thermal inactivation were also determined. Primary application of the crude xylanase preparation in saccharification of corn cob subjected to different pretreatment techniques has been evaluated. The crude xylanase preparation was very promising for saccharification of corn cob pretreated with aqueous ammonia. The maximum yield of reducing sugar was 357?mg/g dry substrate, which revealed that the crude xylanase from A. pullulans could be a very good alternative in saccharification of lignocellulosic biomass for biological fuel generation. This study also provides a basis for further exploitation of globe artichoke by-products in microbial production of several other industrially significant metabolites. 相似文献
79.
菊芋在脱脂乳中对双歧杆菌生长的影响研究 总被引:1,自引:0,他引:1
以菊芋粉为材料,以长双歧杆菌(Blm)和两歧双歧杆菌(Bbm)为实验菌株,研究菊芋在脱脂乳中对双歧杆菌生长的影响,以期为进一步开发菊芋资源和研制双歧杆菌酸奶提供理论依据。结果表明在脱脂乳中加入3%的菊芋粉,凝乳时间有所缩短,在接种Blm的脱脂乳中缩短了0.9h,在接种Bbm的脱脂乳中缩短了1.1h。在脱脂乳中添加3%的菊芋粉后,明显促进了菌体产酸。 相似文献
80.
Freshly cut discs from growing potato tubers were incubated for 3 h with 10 mM orotate or 10 mM uridine. Control discs incubated
without precursors showed a 30–40% decrease of uridine nucleotides, but not of adenine nucleotides. Orotate- and uridine-feeding
led to a 1.5- to 2-fold increase in the levels of uridine nucleotides compared with control discs, and a 15–30% increase compared
with the original values in intact tubers, but did not alter the levels of adenine nucleotides. Between 70–80% of the uridine
nucleotides were present as UDPglucose, 15–25% as UTP, and 2–3% as UDP. The increase of uridine nucleotides involved a similar
relative increase of UDPglucose, UTP and UDP. It was accompanied by a slight stimulation of the rate of [14C]sucrose uptake, a 2-fold stimulation of the rate at which the [14C]sucrose was subsequently metabolised, a small increase in the levels of hexose phosphates, glycerate-3-phospate and ADPglucose,
and a 30% shift in the allocation of the metabolised label in favour of starch synthesis, resulting in a 2.4-fold stimulation
of the rate of starch synthesis. Orotate led to a similar increase of uridine nucleotide levels in the presence of [14C]glucose, but did not significantly alter the rate of glucose uptake and metabolism to starch, nor did it increase the rate
of sucrose resynthesis. The levels of uridine nucleotides were high in tubers on 6 to 10-week-old potato plants, and declined
in tubers on 12 to 15-week-old plants. Comparison with the effect of the uridine nucleotide level in discs shows that the
high levels of uridine nucleotides in tubers on young plants will play an important role in determining the rate at which
sucrose can be converted to starch, and that the level of uridine nucleotides is probably co-limiting for sucrose-starch conversions
in tubers on older plants.
Received: 25 September 1998 / Accepted: 29 December 1998 相似文献