Sex-specific physiological and growth responses to elevated atmospheric CO2 in Silene latifolia Poiret

Dioecy is found in nearly half of the angiosperm families, but little is known about how rising atmospheric CO₂ concentration will affect male and female individuals of dioecious species. We examined gender‐specific physiological and growth responses of Silene latifolia Poiret, a widespread dioecious species, to a doubled atmospheric CO₂ concentration in environmentally controlled growth chambers. Elevated CO₂ significantly increased photosynthesis in both male and female plants and by a similar magnitude. Males and females did not differ in net photosynthetic rate, but females had significantly greater biomass production than males, regardless of CO₂ concentrations. Vegetative mass increased by 39% in males and in females, whereas reproductive mass increased by 82% in males and 97% in females at elevated CO₂. As a result, proportionately more carbon was allocated to reproduction in male and female plants at elevated CO₂. Higher CO₂ increased individual seed mass significantly, but had no effect on the number or mass of seeds per female plant. Our results demonstrated that rising atmospheric CO₂ will alter the allocation patterns in both male and female S. latifolia Poiret plants by shifting proportionally more photosynthate to reproduction.     

Poa annua shows inter-generational differences in response to elevated CO2

Inter-generational effects on the growth of Poa annua (L.) in ambient and elevated atmospheric CO₂ conditions (350 and 550 μl l^–1, respectively) were studied in two different experiments. Both experiments showed similar results. In a greenhouse experiment growth, measured as the numbers of tillers produced per week, was compared for plants grown from first and second generation seeds. Second generation seeds were obtained from plants grown for one whole generation in either ambient or elevated atmospheric CO₂ (‘ambient’ and ‘elevated’ seeds, respectively). First generation plants and second generation ‘ambient’ plants did not respond to elevated CO₂. Second generation ‘elevated’ plants produced significantly more tillers in elevated CO₂. In the second experiment model terrestrial ecosystems growing in the Ecotron and which included Poa annua were used. Above-ground biomass after one and two generations of growth were compared. At the end of Generation 1 no difference was found in biomass production while at the end of Generation 2 biomass increased in elevated CO₂ by 50%. The implications for climate change research are discussed.     

The effects of parental CO2 environment on seed quality and subsequent seedling performance in Bromusrubens

Seeds were collected and compared from parent plants of Bromusrubens L. (Poaceae), an exotic Mojave Desert annual grass, grown in ambient (360 μmol mol⁻¹) and elevated (700 μmol mol⁻¹) CO₂ to determine if parental CO₂ growth conditions affected seed quality. Performance of seeds developed on the above plants was evaluated to determine the influence of parental CO₂ growth conditions on germination, growth rate, and leaf production. Seeds of B. rubens developed on parents grown in elevated CO₂ had a larger pericarp surface area, higher C:N ratio, and less total mass than ambient-developed seeds. Parental CO₂ environment did not have an effect on germination percentage or mean germination time, as determined by radicle emergence. Seedlings from elevated-CO₂-developed seeds had a reduced relative growth rate and achieved smaller final mass over the same growth period. Elevated-CO₂-developed seeds had smaller seed reserves than ambient seeds, as determined by growing seedlings in sterile media and monitoring senescence. It appears that increased seed C:N ratios associated with plants grown under elevated CO₂ may have a major effect on seed quality (morphology, nutrition) and seedling performance (e.g., growth rate and leaf production). Since the invasive success of B. rubens is primarily due to its ability to rapidly germinate, increase leaf area and maintain a relatively high growth rate compared to native annuals and perennial grasses, reductions in seed quality and seedling performance in elevated CO₂ may have significant impacts on future community composition in the Mojave Desert. Received: 11 April 1997 / Accepted: 20 November 1997     

Does Seed Priming Induce Changes in the Levels of Some Endogenous Plant Hormones in Hexaploid Wheat Plants Under Salt Stress？

In order to assess whether salt tolerance could be Improved In spring wheat （Triticum aestivum L.）, the present study was performed by soaking the seeds of two cultlvars, namely MH-97 （salt sensitive） and Inqlab-91 （salt tolerant）, for 12 h In distilled water or 100 mol/m^3 CaCl2, KCI, or NaCI. Primed seeds from each treatment group and non-primed seeds were sown In a field In which NaCI salinity of 15 dS/m was developed. Priming of seeds with CaCl2, followed by priming with KCI and NaCI, was found to be effective In alleviating the adverse effects of salt stress on both wheat cultivars In terms of shoot fresh and dry weights and grain yield. Priming with CaCl2 alleviated the adverse effects of salt stress on hormonal balance In plants of both cultlvars. In MH-97 plants, CaCl2 pretreatment considerably reduced leaf absclslc acid （ABA） concentrations and Increased leaf free salicylic acid （SA） concentrations under both saline and non-saline conditions. In contrast, In the Inqlab-91 plant, CaCl2 Increased free Indoleacetic acid （IAA） and indolebutyrlc acid （IBA） content. However, priming of seeds with CaCl2 did not alter free polyamlne levels in either cultlvar, although spermldlne levels were considerably lower In plants raised from seeds treated with CaCl2 for both cultlvars under saline conditions. Priming with KCI Increased growth In Inqlab-91 plants, but not In MH-97 plants, under saline conditions. The salinity Induced reducUon In auxins （IAA and IBA） was alleviated by NaCI priming In both cultlvars under saline conditions. However, NaCI Increased leaf free ABA content and lowered leaf SA and putresclne levels In Inqlab-91 plants under saline conditions. In conclusion, although all three priming agents （I.e. CaCl2, KCI, and NaCI） were effective In alleviating the adverse effects of salt stress on wheat plants, their effects on altering the levels of different plant hormones were different In the two cuItlvars.     

The calcifuge behaviour of Visearía vulgarís

Soil factors responsible for the inability of Visearía vulgaris to colonize or survive on calcareous soils in Scandinavia were studied using experiments with plant establishment from seeds and re-establishment of mature plants, in soils of naturally differing or artificially varied chemical properties. Limestone soil proved less suitable for re-establishment of mature plants, and establishment from seeds was not possible in this soil. The plants grown on limestone had a very low phosphorus content and displayed deficiency symptoms. Acid leptite soil and soil from the A-horizon of a dystric cambisol were suitable for plant establishment from seeds and re-establishment of adult individuals, respectively. However, growth increased significantly when pH-KCl was raised to 7.6 by adding CaC0₃. Establishment from seeds was successful in the Archaean and Ordovician limestone soils only when CaHP0₄ was added. The calcifuge behaviour of Visearía vulgaris is not due to negative effects of a high pH or a high Ca concentration in the soil. Inability to utilize the native phosphorus of such soils is the most evident explanation.     

RECIPROCAL DIFFERENCES IN INTRASPECIFIC CROSSES OF TOBACCO RESULT FROM EMBRYO DEATH

Tetraploid tobacco plants (Nicotiana tabacum) derived from cultured cell lines (TC) are partially cross-incompatible with their diploid progenitors (C). C × TC crosses (TC-derived tetraploids as the pollen parent) yield only 2% viable seed. The remaining seeds are normal size but lack an embryo (apoembryonic seeds). Apoembryonic seeds do not occur in the reciprocal TC × C crosses. Sections of ovules from C × TC crosses revealed that an embryo formed but that embryo growth slowed at 5 days postpollination and that by the 12th day following pollination, the embryo had disappeared although the ovule continued to develop. Endosperm degeneration occurred concurrently with embryo death. Culturing ovules from C × TC crosses has increased the yield of F₁ plants from 2% to as much as 25% indicating that embryo rescue is possible. Surviving F₁ plants from TC × C crosses have close to triploid chromosome numbers and are fertile.     

青藏高原53种菊科植物种子中碳、氮、磷含量与种子大小和海拔的关系

以青藏高原东北缘广泛分布的53种常见菊科植物种子为研究材料,以重铬酸钾外加热法和流动注射分析仪测定种子中碳、氮、磷含量,探讨种子中碳、氮、磷组成及分配是否随种子大小及生境海拔高度变异,为进一步探讨植物对环境变化的响应提供理论依据。结果表明:(1)53种菊科植物种子大小差异显著,且随海拔升高种子有变小的趋势。(2)53种菊科植物种子中C、N、P含量及其比值差异显著,不同海拔梯度的物种种子中C、N、P含量及其比值差异不显著,但C、N含量有随海拔升高增加的趋势,而P含量有随海拔升高降低的趋势。(3)种子大小变异并不影响其C的相对含量,但N、P含量与种子大小呈显著负相关关系,C/N、C/P、N/P与种子大小呈显著正相关关系,即种子越小,种子中N、P相对含量越高。因此,高海拔条件下,种子中积聚相对较多的C、N可以为其生长发育初期提供较高的能量及较多的蛋白质合成,从而增强幼苗抵御恶劣环境条件的能力,提高幼苗的存活率;较小种子中相对较高的N、P含量可以为早期幼苗提供足够的蛋白质和核糖体,帮助幼苗快速生长,从而克服其产生较小幼苗的劣势。研究表明,植物种子中C、N、P含量随种子大小及海拔的变异趋势是一种适应性选择的结果。     

Reproductive capacity,germination and survivorship of Lithospermum caroliniense on Lake Huron sand dunes

Summary The flowering of pin (long-styled) and thrum (short-styled) plants in populations of Lithospermum caroliniense (Walt.) McMill. was synchronized and both morphs had an extended period of flowering. The plants produced a large number of flowers that did not set seeds — hence the seed production per plant was very low. The seeds showed strong dormancy. Even under natural conditions, only 19% of the seeds produced seedlings. However, seedling survival was relatively high probably due to rapid root growth to deeper layers where moisture was not limiting. The probability of survival of seedlings increased with age; survival of seedlings, juveniles and adults after 2 years was 39, 68 and 98%, respectively. The dry weight of roots increased from 10% in June to 42% in September whereas the proportion of biomass contained in leaves, stems and hypocotyls decreased with age.     

Role of aminolevulinic acid in improving biomass production in Vigna catjung, V. mungo, and V. radiata

A precursor in tetrapyrrole biosynthesis, 5-aminolevulinic acid (ALA), was applied via presowing soaking in Vigna catjung, V. mungo, and V. radiata. ALA increased plant growth and influenced dry matter accumulation in leaves, stems, and pods through increased chlorophyll content and photosynthetic CO₂ absorption. At harvest, ALA treated plants had increased number of pods per plant, seeds per pod, 100 seed dry matter, biological yield, and the harvest index. Therefore, pretreatment of seeds with optimal concentration of ALA is recommended for improving the growth and productivity of tropical legumes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Some Physiological Parameters and Seed Lipid Composition of Transgenic Tobacco Plant

To see the effects of foreign gene introduction on the physiological performance and the quality and quantity of seed lipids, we studied transgenic tobacco plant as a model system, as tobacco seeds are oil seeds. Using Agrobacterium Ti plasmid based vectors, tobacco plants cv Petit Havana were transformed by NPT II gene as selectable marker. Transformed T₀ generation plants raised in tissue culture were transferred to pots and selfed. From the seeds, T₁ generation plants were grown in pots and their physiological performance was assessed. The transgenic plants showed slightly slower rates of germination and growth. Total chlorophyll content, chlorophyll a/b ratio and specific leaf weight, however, remained unchanged. The transgenic plants also had delayed flowering. However, total protein, lipid content and fatty acid composition of lipids of seeds in transgenic plants did not show appreciable difference from the seeds from control plants. Thus the physiological cost of transgenic plant for the extra genetic load was only marginal, if any.     

VARIATION IN POPULATION GROWTH RATE IN THE WOODLAND ANNUAL IMPATIENS PALLIDA (BALSAMINACEAE)

Variation in population growth rate over environmental gradients was determined for the annual Impatiens pallida (Balsaminaceae), by monitoring age- and size-specific survivorship and fecundity in five populations of this summer-flowering and primarily woodland species. All I. pallida seedlings emerged within a few days of each other and a size hierarchy was established within a month, and remained unchanged thereafter. Light and initial seedling density together explained 67% of the variance in mean adult plant size. As a result of differences among populations in the amount of disturbance, survivorship to the time of floral bud production ranged from 39% to 93% of the initial seedling total. Survivorship during the reproductive period was most affected by plant size and soil moisture. For plants surviving to flowering time, the probability of setting seed, the type of seed and the number of seeds produced per plant were significantly positively correlated with plant size. More than 82% of all seeds were produced by plants greater than or 1 m tall. Cleistogamy was the major form of reproduction in 4 out of 5 populations monitored. The net reproductive rate (R₀) differed greatly among populations, ranging from 1.23 to 16.27. Population growth rate increased with increasing resource availability and decreasing disturbance during the growing season. The magnitude of R₀ depended primarily on 1) timing, intensity and frequency of disturbance, 2) length of the reproductive period, and 3) population size structure.     

Selection of somaclonal variants with low-temperature germinability in melon (Cucumis melo L.)

Summary Plants were regenerated from adventitious buds and somatic embryos (R₀) of melon (Cucumis melo L.), the cultivar Andes. Somaclonal variants of melon with low temperature germinability were selected from the progenies (R₁) of R₀ plants. Among 5,618 R₁ seeds harvested from 23 R₀ plants that were regenerated from adventitious buds 4 seeds germinated after 5 days of culture at 15 °C (selection rate; 0.07%). However, among 374 R₂ seeds harvested from 2 R₁ plants no seed germinated after 7 days of culture at 14 °C. Among 9,181 R₁ seeds harvested from 50 R₀ plants regenerated from somatic embryos 110 seeds germinated after 5 days of culture at 15 °C (selection rate; 1.20%). Among 3,717 R₂ seeds harvested from 17 R₁ plants 113 seeds germinated after 7 days of culture at 14 °C (selection rate; 3.04%). R₃ seeds were collected from these R₂ plants following self-pollination. Forty-five of the 47 lines (R₃) originated from 10 R₀ plants showed higher germination rates than that of the original cultivar. Selected lines with low-temperature germinability showed greater fruit growth rate than the original cultivar during the middle stage when they were cultivated in a greenhouse under low-temperature conditions. Of fruits harvested from 31 lines, 15 lines showed greater fruit volume than the original cultivar.     

Effect on the Progeny of Applying Different Day Length and Hormone Treatments to Parent Plants of Lactuca scariola

Seedlings of the self-fertilizing species Lactuca scariola L. grown continuously in 8 h days did not flower even one year from sowing. Seedlings grown in 16 h days uatil flower buds appeared 96 days after germination were either transferred to 8 h days or treated weekly with gibberellic acid (GA₃), abscisic acid (ABA) or chlormequat (CCC) and retained, together with untreated control plants, in 16 h days. Each growth regulator caused characteristic morphological changes in the treated plants. All these plants flowered and produced seeds but the seeds showed distinct differences in weight, in their time to germination and in the seedlings which they produced. Germination and seedling characters depended on the light regime during germination as well as on the chemical applied to the parent plant and the rate of application. The parental treatment also affected the shape and size of the seedlings on a given day after germination, and certain treatments of the parent plant (transfer from long to short days and treatment with CCC in long days) advanced the flowering date of the seedlings. The gibberellin level in the seeds was raised, in increasing order, by treatment of the parent plant with 100 mg/1 GA₃, transfer from long to short days, 10 mg/1 GA₃, and 5000 mg/l CCC. It is suggested that the effect of day length on plant performance is mediated by the level of growth regelating substances within the plant and that the behaviour of seeds can be modified by the parental environment via the accumulation of different levels of certain growth factors in the seeds. A rise of one growth substance in the parent plant can result in the accumulation of a different one in the seeds.     

Methods to Promote Germination of Dormant Setaria viridis Seeds

Setaria viridis has recently emerged as a promising genetic model system to study diverse aspects of monocot biology. While the post-germination life cycle of S. viridis is approximately 8 weeks long, the prolonged dormancy of freshly harvested seeds can more than double the total time required between successive generations. Here we describe methods that promote seed germination in S. viridis. Our results demonstrate that treating S. viridis seeds with liquid smoke or a GA₃ and KNO₃ solution improves germination rates to 90% or higher even in seeds that are 6 days post-harvest with similar results obtained whether seeds are planted in soil or on gel-based media. Importantly, we show that these treatments have no significant effect on the growth of the adult plant. We have tested these treatments on diverse S. viridis accessions and show variation in their response. The methods described here will help advance research using this model grass species by increasing the pace at which successive generations of plants can be analyzed.     

Effects of neodymium magneto-priming on seed germination and salinity tolerance in tomato

Earth's biosphere is surrounded by magnetic fields that affect all living organisms. A plant's response to magnetic fields is displayed in terms of its seed's vigor, growth, and yield. Examining seed germination in such magnetic fields is the first step in the investigation of how magnetic fields might be used to enhance plant growth and maximize crop performance. In this study, salinity-sensitive Super Strain-B tomato seeds were primed with the northern and southern poles of neodymium magnets of 150, 200, and 250 mT. The magneto-primed seeds showed a significant increase in germination rate and speed, where the orientation of the magnet was identified as being crucial for germination rate and the orientation of seeds towards the magnet was shown to affect the germination speed. The primed plants exhibited enhanced growth characteristics, including longer shoots and roots, larger leaf area, more root hairs, higher water content, and more tolerance to salinity levels, up to 200 mM NaCl. All magneto-primed plants showed a significant decrease in chlorophyll content, continuous chlorophyll fluorescence yield (Ft), and quantum yield (QY). The salinity treatments decreased all chlorophyll parameters in control plants, significantly, but did not lower such parameters in magneto-primed tomatoes. The results of this study illustrate the positive effects of neodymium magnet on the growth and development of tomato plants in terms of their germination, growth, and salinity tolerance, and negatively affected the chlorophyll content in tomato leaves. © 2023 Bioelectromagnetics Society.     

Early Sprouting and First Stages of Growth of Rice Seeds Exposed to a Magnetic Field

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.     

Effect of 28-homobrassinolide on antioxidant capacity and photosynthesis in Brassica juncea plants exposed to different levels of copper

A sand culture experiment was conducted to study ameliorative role of 28-homobrassinolide (HBL) in Brassica juncea seedlings raised from the seeds treated with water, or 10⁻¹⁰, 10⁻⁸ and 10⁻⁶ M 28-homobrassinolide (HBL) and grown in the presence of copper (50, 100 and 150 mg kg⁻¹ sand) and sampled at 30 days after sowing. The plants grown in the presence of copper exhibited a significant decline in growth, chlorophyll and photosynthetic parameters. However, the activity of antioxidant enzymes: catalase (E.C. 1.11.1.6), peroxidase (E.C. 1.11.1.7) and superoxide dismutase (E.C. 1.15.1.1) and the content of proline increased in the plants grown under copper stress and/or raised from treatment with HBL. However, H₂O₂ content increased significantly in copper-treated plants and decreased in plants given HBL treatment. Treatment of seeds with HBL improved the growth, photosynthetic parameters and antioxidant enzymes and also improved in the plants grown under copper stress. The elevated antioxidant enzyme and proline might be responsible to overcome the toxic effects of copper in B. juncea.     

The effect of pollination on the growth and reproduction of oilseed rape (Brassica napus)

Phenotypic plasticity is an organism's ability to alter its development and life history in response to environmental conditions. In plants, biotic and abiotic factors drive the distribution of resources between growth and reproductive traits. One such biotic factor is pollination. Studies show that wind and insect pollination enhance oilseed rape (Brassica napus) yield. However, the impact of pollination on resource allocation towards growth and reproduction is less understood. We conducted a controlled experiment to assess the effect of pollination on growth and functional reproductive traits. We compared two simulated supplementary pollen deposition methods (representing wind and insect pollination) alongside a non-supplementary control. Pollinated plants allocated resources towards growth and reproduction similarly, irrespective of deposition method. Plants receiving no supplementary pollination produced fewer seeds, allocating resources to growth, more prolific and persistent flowering, and heavier seeds. Pollinated plants had a reduced flowering period and were shorter, indicating resources were allocated to seed production rather than growth or the production of additional flowers. This allocation of resources from growth and flowering metrics can increase yield directly through increased seed production and indirectly through shorter plants and a reduced flowering period with seeds that mature earlier (agronomically beneficial traits).Wind and insect pollination can enhance and stabilise oilseed rape yield under various environmental conditions by acting in complementary ways. Since pollination limits yield in oilseed rape, it must be considered an input that can be actively managed. Successful management of pollination services requires growers to detect pollination deficits. Inadequately pollinated oilseed rape plants exhibit apparent morphological changes (e.g. taller plants that flower for longer), acting as an early warning to growers. Equipping growers with this knowledge provides them with a means of detecting deficits and thus enables them to take positive action to restore pollination services by introducing honeybees or enhancing wild pollinators.     

Application of bio-fertilizers for enhancing growth and yield of common bean plants grown under water stress conditions

This study was planned to enhance the growth and productivity of common bean plants (Phaseolus vulgaris L.) grown under different water stress level by using different microorganisms as bio-fertilizer agents. Water stress is a international problem that effects on morphological, functional and chemical processes of plants occasioning in altering growth, yield and water relations of economic plants like common bean plants. The interaction effect between water stress (WW as recommended irrigation after 6 days, WS1 after 12 days and WS2 after 18 days) and inoculation with different microorganisms [AMF (Glomus mosseae) and endophytic bacteria, (Bacillus amyloliquefaciens)] used alone or in mixed was examined on the development and productivity of common bean plants. Mutual application of AMF and endophytic bacteria significantly increased the average values of most of growth, water relations (photosynthetic rate, transpiration rate and stomatal conductance) and yield parameters of common bean plants grown at WS1 and WS2 comparing with non-colonized plants. In this connection, colonization with AMF and endophytic bacteria with WS1 are the greater pods number, pod length, pods weight, 100 seeds weight, Yield by ton /Fed and water-use efficiency (WUE) by ton/ m³ than other treatments. Common bean yielded seeds had significantly increased nutrients content (nitrogen, potassium, phosphorus, magnesium and calcium), vitamin B₁, Folic acid, crude protein and crude fibers at AMF + endophytic bacteria under second water stress (WS1) when compared to other treatments.     

Adaptation and growth response of Arabidopsis thaliana to deuterium

Summary Arabidopsis seeds were sown aseptically on mineral media containing between 0 and 90% of heavy water (D₂O). Initially, a D₂O level of over 50% was lethal for the plants. However, after culture for six successive generations on 50% D₂O, plants were capable of growing marginally on media containing up to 70% D₂O, but not higher. With increasing concentration, deuterium progressively delays germination, slows growth, reduces survival, results in bleaching of the leaves and delays flowering. Pollen fertility is not affected measurably but seed set is reduced with increasing levels of deuteration so that at 70% D₂O few seeds were obtained. The viability of the seeds harvested from plants grown on deuterated media is low. No chlorophyll or morphological mutants were observed among a large number of plant progenies. Seeds from plants cultured on D₂O media for several generations grow normally on proteated media in the very first generation.