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931.
Invasive terrestrial plants often substantially reshape environments, yet how such invasions affect terrestrial snail assemblages remains understudied. We investigated how snail assemblages in deciduous forest soils with dense Berberis thunbergii (Japanese barberry), an invasive shrub in eastern North America, differ from forest areas lacking the shrub. Leaf litter and soil samples were collected from forest patches with dense B. thunbergii understories and adjacent control areas within two exurban forest tracts in western Pennsylvania, U.S.A. Snails were identified to species and quantified by standard diversity metrics. Contrary to our expectations, snails were significantly more abundant and diverse in B. thunbergii-invaded areas. Despite differences in abundance, the snail community composition did not differ between invaded and control habitats. The terrestrial snail assemblage we observed, which was composed entirely of native species, appears to respond favorably to B. thunbergii invasion and therefore may not be negatively impacted by physicochemical changes to soils typically observed in association with the plant. Such findings could reflect the fact that B. thunbergii likely creates more favorable habitat for snails by creating cooler, more humid, and more alkaline soil environments. However, the snail assemblages we retrieved may consist mostly of species with high tolerance to environmental degradation due to a legacy of land use change and acid deposition in the region. 相似文献
932.
Md. Quamruzzaman Md. Jahedur Rahman Jasim Uddain Md. Dulal Sarkar 《Journal of Plant Interactions》2018,13(1):306-314
Boron application at proper concentration is necessary to enhance the leaf gas exchange, physiological growth, reproductive development and nutritional improvement of crops. Therefore, an experiment was conducted to study the effects of boron to evaluate the effect on the leaf gas exchange, reproductive development, physiological and nutritional changes of peanut. Treatments comprised six levels of boron (B), viz., B1 (0?ppm), B2 (0.5?ppm), B3 (1?ppm), B4 (2?ppm), B5 (4?ppm) and B6 (8?ppm). Results revealed that the vegetative growth, physiological growth parameters, leaf gas exchange, reproductive characters, peg strength, shelling (%) and nutritional elements were increased for boron application. Some vegetative, physiological and reproductive traits are positively correlated with each other. Thus, this finding showed that boron can be used to culture peanut as it provides high yield and nutritional properties. 相似文献
933.
Rice plants are highly susceptible to Fe-deficiency. Under nutrient deprivation, plant cells undergo extensive metabolic changes for their continued survival. To provide further insight into the pathways induced during Fe-deficiency, rice seedlings were grown for 3, 6 and 9 days in the presence or absence of Fe. Using RDA (Representational Difference Analysis), sequences of 32 induced genes in rice shoots under Fe-deficiency were identified. About 30% of the sequences found have been previously reported as responsive to other abiotic and even biotic stresses. However, this is the first report that indicates their relation to Fe deprivation. Differential expression of selected genes was confirmed by semi-quantitative RT-PCR analysis. The identification of classical senescence-related sequences, such as lipase EC 3.1.1.-, ubiquitin-conjugating enzyme EC 6.3.2.19, beta-Glucosidase EC 3.2.1.21 and cysteine synthase EC 2.5.1.47, besides the higher accumulation of total soluble sugars prior to the decrease of total chlorophyll content in Fe-deficient leaves, indicate that sugar accumulation may be one of the factors leading to premature leaf senescence induced by Fe-deficiency. 相似文献
934.
The importance of nutritional regulation of plant water flux 总被引:1,自引:0,他引:1
Transpiration is generally considered a wasteful but unavoidable consequence of photosynthesis, occurring because water is
lost when stomata open for CO2 uptake. Additionally, transpiration has been ascribed the functions of cooling leaves, driving root to shoot xylem transport
and mass flow of nutrients through the soil to the rhizosphere. As a consequence of the link between nutrient mass flow and
transpiration, nutrient availability, particularly that of NO3
−, partially regulates plant water flux. Nutrient regulation of transpiration may function through the concerted regulation
of: (1) root hydraulic conductance through control of aquaporins by NO3
−, (2) shoot stomatal conductance (g
s) through NO production, and (3) pH and phytohormone regulation of g
s. These mechanisms result in biphasic responses of water flux to NO3
− availability. The consequent trade-off between water and nutrient flux has important implications for understanding plant
distributions, for production of water use-efficient crops and for understanding the consequences of global-change-linked
CO2 suppression of transpiration for plant nutrient acquisition. 相似文献
935.
Distribution of plants and the expression of traits associated with environmental variation can be affected by both average
conditions and the variance in conditions including extreme climatic events. We expect that these same factors should affect
the distribution of plants in hybrid zones between ecologically distinct species where the hybrids should occupy ecotones
or intermediate habitats. We evaluated water availability and leaf morphological differences among parental and hybrid populations
of herbaceous perennial plants in the Piriqueta caroliniana complex along environmental gradients in Southeastern North America. We focus on two taxa in this group; the viridis morphotype, which occurs in southern Florida, and the caroliniana morphotype, which is distributed from northern Florida to southern Georgia. Advanced-generation hybrid derivatives of these
morphotypes occupy a broad geographic region that extends across much of central Florida. Overall, we found that hybrid populations
occurred in significantly drier locations, indicating that their habitat requirements are transgressive (i.e., exceeding parental
values) rather than intermediate to the parental morphotypes. Water availability differed between the two sampling years,
and plants displayed morphological changes in response to these changes in moisture. During the drier year, leaves were narrower
and more hirsute, corroborating experimental results that these leaf traits are plastic, and confirming that plasticity occurs
in natural habitats. Hybrids exhibited intermediate leaf traits (shape and size) across both years, and displayed transgressive
(hair density) leaf traits during the drier year. The apparent canalization of the hybrids’ leaf morphological traits may
contribute to their tolerance of variable environmental conditions and may partially explain why they have displaced the caroliniana morphotype in central Florida. 相似文献
936.
Herbivorous insects identify their host plants either by structural features, chemical cues, or a combination. Some insects
probe the host leaf prior feeding or oviposition, other species use olfactorial cues or compounds somewhere on the surface.
Insects attacking Brassicaceae are no exception, some are attracted and stimulated by volatile isothiocyanates (ITC), many
others depend fully on the non-volatile glucosinolates (GS) for host-plant recognition and acceptance. Since most insects
have no access to the leaf interior investigators concluded that GS must be present on the leaf surface and ITC in the headspace.
However, peelings of mechanically removed surface waxes were devoid of measurable amounts of GS, whereas solvent surface extractions
revealed a correlation between stomatal conditions and GS concentrations. Both observations lead to the conclusion that the
presence of GS on the top leaf surface is rather unlikely. In the experimental part we show that a chloroform/methanol/water
(2:1:1 vol/vol/vol) solvent leaf extract contains GS and, in addition, thia-triaza-fluorenes (TTF), other oviposition stimulants
of the cabbage root fly, Delia radicum. Electrophysiological investigations showed that both, GS and TTF stimulated specific receptor neurones of the fly. We suggest
that these compounds probably originated from deeper leaf layers and that herbivorous insects may penetrate the wax layer
and perceive the stimulating compounds in deeper layers or through the stomata. 相似文献
937.
The leaf area index (LAI) development, which is related to the capacity of light interception, and the maximum leaf photosynthetic rate (Pmax), which related to the efficiency of light energy conversion, are two key photosynthetic traits to increase the utilization efficiency of solar energy. Using the Guangdong rice "Qiguizao', which belongs to low light adapt-able ecotype and characterized by quick developing LAI, and the US rice "Lemont', which belongs to high light adaptable ecotype and characterized by higher light saturation point of photosynthesis, as parents to make a hybrid (Le/Qi) by means of chemical hybridizing agent, the authors successfully solved the contradiction between LAI and Prix. The hybrid Le/Qi not only showed quick developing LAI, but also higher Pmax, less or no midday depression of photosynthesis and less or no photooxidation under high light induced conditions. The photosynthetic productivity and adaptability of Le/Qi were increased over 20 % and improved a lot according to the growth analysis under different light and temperature conditions in growth chambers and field trials in flatlands, hilly land or mountain area. This study indicated that utilization of high light adaptable US elite rice as parent to make a hybrid with Guangdong low light adaptable local elite rice by means of chemical hybridizing agent is an effective and quick breeding approach to improve the adaptability of Guangdong rice to high light and to increase the photosynthetic productivity in turn the economic income. 相似文献
938.
《Electromagnetic biology and medicine》2013,32(2):157-166
The effects of a stationary magnetic field on the germination of rice seeds (Oryza sativa, L.) and on the initial stages of growth of rice plants have been evaluated. In both tests, the seeds were exposed to one of two magnetic field strengths (125 or 250 mT) for different times (1 min, 10 min, 20 min, 1 h, 24 h, or chronic exposure) as 12 separate treatments (doses D1–D6 for 125 mT and doses D7–D12 for 250 mT). Nonexposed seeds were used as controls (C). The mean germination time (MGT) was significantly reduced compared to control when seeds were exposed to magnetic field (54.00 h for D5 and D11, and 58.56 h for control). The parameters T1 and T10, times required to obtain 1 and 10% of germinated seeds, were also reduced. The T10 of control seeds was 44.40 h, while treatments D5, D6, D11, and D12 gave rise to values of 36.00, 36.96, 32.64, and 39.36 h, respectively. The higher germination rate of treated seeds obtained in the germination test is in agreement with the higher lengths and weights of rice plants exposed to a magnetic field recorded on the growth tests. All the parameters measured were over the control ones, although the highest lengths and weights of rice plants were obtained for chronic exposure to magnetic field (doses D6 and D12). Stem length of control plants (45.36 mm) measured at the tenth day was significantly lower than that obtained for doses D6 (58.58 mm) and D12 (80.63 mm); the same behavior was observed on total length, stem weight, and total weight. Our finding indicates that this type of magnetic treatment clearly affects germination and the first stages of growth of rice plants. 相似文献
939.
940.
A comparative study of leaf anatomy on Aniselytron Merr. and Calamagrostis Adans. s. l. was conducted to review the systematic status of Aniselytron Merr. Calamagrostis s. l. exhibits wide variation in many features, but basic leaf structures of the genus remain constant: absence of a midrib-keel; median and large vascular bundles are central, with double sheaths, accompanied by girders both adaxially and abaxially; prickles have a bulbous base and are not sunken; the abaxial epidermal cells are short and wide and relatively thick-walled. Aniselytron differs from Calamagrostis s. l. in: midrib-keel is present, consisting of a large central bundle with small ones on either side; all vascular bundles are abaxially situated, with abaxial girders only, parenchyma takes the place of the adaxial sclerenchyma; the bases of the prickles are sunken and are not bulbous; the abaxial epidermal cells are tall and thin-walled. These distinct anatomical features, in combination with the differences in spikelet structure and habitat, suggest that Aniselytron should be generically separated from and not merged with Calamagrostis s. l. Due to the adaxial parenchyma in the midrib which has never been found in Pooideae, Aniselytron might have a relationship with some other subfamily. 相似文献