全文获取类型
收费全文 | 147篇 |
免费 | 9篇 |
国内免费 | 21篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 16篇 |
2012年 | 11篇 |
2011年 | 3篇 |
2010年 | 5篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 9篇 |
2006年 | 4篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 906 毫秒
1.
Fruit photosynthesis 总被引:12,自引:1,他引:11
Abstract. In addition to photosynthesis as in the leaf, fruit possess a system which refixes CO2 from the mitochondrial respiration of predominantly imported carbon. This pathway produces malate by the action of phosphoenolpyruvate carboxylase, PEPC, (E.C. 4.1.1.31) and appears to be regulated primarily by the cytosolic concentration of HCO3/CO2 and malate. Malate is stored in the vacuole as malic acid, constituting a major carbon pool and a potential substrate for respiration. The PEPC in apple fruit proves to be an efficient form of the enzyme with low Michaelis constants, i.e. Km = 0.09 mol m-3 PEP and 0.2 mol m–3 HCO3, and large Ki= 110 mol m-3 HCO3. In fleshy fruit, chlorophyll and chloroplasts are unevenly distributed; they resemble the C3 sun-type and arc concentrated in the perivascular tissue, with smaller chloroplasts, fewer grana per chloroplast and a larger degree of vacuolation than commonly found in a leaf of the same species. Fruit photosynthesis often compensates for respiratory CO2 loss in the light. However, due to respiration in the dark, CO2 loss is in excess of photosynthetic gain in the light, such that a continual loss of CO2 was observed in the diurnal cycle and which is maintained throughout fruit development. The rate of CO2 exchange decreases on a fresh weight or surface basis, but increases with fruit ontogeny on a per fruit basis, causing accumulation of several percent CO2 in the internal cavity. Stomata are present in the outer epidermis of those fruits examined, but with a 10-to 100-fold lesser frequency than in the abaxial epidermis of leaf of the same species. The number of Stomata is set at anthesis and remained constant, while the stomatal frequency decreases as the fruit surface expands. Stomata are as sensitive as in leaves in the early stages of fruit development, but often are transformed into lenticels during fruit ontogeny, thereby decreasing the permeability of the outer epidermis. The discrepancy between the CO2-concentrating mechanism provided by PEPC analogous to C4/CAM Photosynthesis and the kinetics of fruit PEPC, characteristic of C3/non-autotrophic tissue, suggests the definition of a new type of ‘fruit photosynthesis’ rather than its categorization within an existing type. 相似文献
2.
David Bouchez Paola Vittorioso Béatrice Courtial Christine Camilleri 《Plant Molecular Biology Reporter》1996,14(2):115-123
We have designed a new method for the recovery of T-DNA flanking sequences from T-DNA-tagged lines ofArabidopsis thaliana. Since most transformation vectors in use contain a plant-selectable marker for kanamycin resistance, we can use the 3′ part
of thenptII coding region from the T-DNA to complement the bacterial 5′ region of thenptII gene from Tn5 to reconstruct a functional kanamycin-resistance gene inEscherichia coli. We have constructed a vector that contains the 5′ part of thenptII gene from Tn5 up to the uniquePst I site. By cloning total DNA from transformed lines in this vector, we were able to select directly for clones containing
a T-DNA fragment, which reconstitutes a functional kanamycin gene, and a fragment of arabidopsis genomic DNA adjacent to the
insertion. Flanking sequences up to 4 kb were rescued by this system. 相似文献
3.
In each of two experiments done under controlled conditions, starting at bloom, 4 humidity treatments were applied to potted trees of apple ( Malus pumila Mill. cv. Cox's Orange Pippin), i. e. in experiment 1: (1) high humidity throughout, (2) low humidity throughout, (3) low humidity for 7 weeks followed by high humidity for 6-7 weeks, and (4) the reverse (first high and then low humidity); in experiment 2: (1) day/night humidity high/high, (2) low/low, (3) low/high, and (4) high/low.
In both experiments high humidity favoured shoot growth appreciably. Change from low to high humidity after 7 weeks resulted in some growth stimulation but in the reverse situation growth was markedly reduced. Shoot growth responded little to different night humidities. In the two experiments fruit growth was little affected by treatments. In experiment 2 irrespective of night humidity, water consumption was higher at low than at high day humidity. In the high/low humidity regime water use during the night was high and leaf water potential low, relatively; during the day water potential was little affected by treatments.
At any time leaf Ca and Mg were clearly highest at low day humidity; night humidity had no effect. Leaf K did not respond to treatments. Fruit Ca at high humidity throughout was lower than at low humidity throughout. Increasing humidity later in the season was ineffective but a decrease at that time tended to reduce fruit Ca slightly. The clearly lowest Ca values occurred in the high/low day/night treatment. Fruit K and Mg were not or hardly affected by treatments.
The findings are discussed in terms of humidity effects on transpiration, shoot and fruit growth, and xylem mineral concentration and ion exchange translocation along the xylem walls. 相似文献
In both experiments high humidity favoured shoot growth appreciably. Change from low to high humidity after 7 weeks resulted in some growth stimulation but in the reverse situation growth was markedly reduced. Shoot growth responded little to different night humidities. In the two experiments fruit growth was little affected by treatments. In experiment 2 irrespective of night humidity, water consumption was higher at low than at high day humidity. In the high/low humidity regime water use during the night was high and leaf water potential low, relatively; during the day water potential was little affected by treatments.
At any time leaf Ca and Mg were clearly highest at low day humidity; night humidity had no effect. Leaf K did not respond to treatments. Fruit Ca at high humidity throughout was lower than at low humidity throughout. Increasing humidity later in the season was ineffective but a decrease at that time tended to reduce fruit Ca slightly. The clearly lowest Ca values occurred in the high/low day/night treatment. Fruit K and Mg were not or hardly affected by treatments.
The findings are discussed in terms of humidity effects on transpiration, shoot and fruit growth, and xylem mineral concentration and ion exchange translocation along the xylem walls. 相似文献
4.
5.
《Cell cycle (Georgetown, Tex.)》2013,12(19):3527-3528
Comment on: Crismani W, et al. Science 2012; 336:1588-90. 相似文献
6.
7.
8.
9.
Philip J. White Timothy S. George Peter J. Gregory A. Glyn Bengough Paul D. Hallett Blair M. McKenzie 《Annals of botany》2013,112(2):207-222
Background
Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilizers.Scope
This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future. 相似文献10.
Aleksandar
. Kosti Uro M. Gai Mirjana B. Pei Sladjana P. Stanojevi Miroljub B. Bara Marina P. Ma
ukanovi‐Joci Stevan N. Avramov
ivoslav Lj. Tei 《化学与生物多样性》2019,16(3)
This study was aimed at investigating the phytochemical composition and antioxidant capacity of rhizomes, above‐ground vegetative parts and flowers of three Iris species: Iris humilis Georgi , Iris pumila L. and Iris variegata L. UHPLC‐Orbitrap MS analysis was used for determination of phytochemical profile. Total pigments, phenolics, flavonoids, soluble sugars and starch content as well as ABTS antioxidant capacity were also determined. In total, 52 phenolics compounds were identified with 9 compounds (derivatives of iriflophenone, apigenin C‐glycosides, luteolin O‐glycoside, isoflavones derivatives of iristectorigenin, dichotomitin, nigracin and irilone) never reported before in Iris spp. Differences in phenolic composition profile, pigments, soluble sugar, starch, total phenolics and flavonoids content and total antioxidant capacity were found among Iris species and different part of plants. Significant correlation between total phenolic content and antioxidant capacity was determined. The obtained results are comparable with those obtained for medical plants. These findings could be useful for fingerprinting characterization of Iris species and estimation of possible use in pharmaceutical industries. 相似文献