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1.
Photosynthetic parameters were measured in two invasive weeds, Mikania micrantha and Chromolaena odorata, grown in soil under full, medium, and low irradiance and full, medium, and low water supply. Both species showed significantly
higher net photosynthetic rate, quantum yield of PS 2 photochemistry and photochemical quenching coefficient under high than
low irradiance. For M. micrantha, low irradiance caused decreased chlorophyll content (Chl), Chl a/b ratio and maximum photochemical efficiency of PS 2 (Fv/Fm), while drought decreased Chl content and Fv/Fm and increased nonphotochemical quenching (NPQ). However, these parameters were much less affected in C. odorata except that Chl content and NPQ slightly increased under drought and high irradiance. High irradiance increased xanthophyll
pools in both species, especially M. micrantha under combination with drought. 相似文献
2.
The effects of shade on the growth, leaf photosynthetic characteristics, and chlorophyll (Chl) fluorescence parameters of
Lycoris radiata var. radiata were determined under differing irradiances (15, 65, and 100% of full irradiance) within pots. The HI plants exhibited a
typical decline in net photosynthetic rate (P
N) during midday, which was not observed in MI- and LI plants. This indicated a possible photoinhibition in HI plants as the
ratio of variable to maximum fluorescence (Fv/Fm) value was higher and the minimal fluorescence (F0) was lower in the, and LI plants. Diurnal patterns of stomatal conductance (g
s) and transpiration rate (E) were remarkably similar to those of P
N at each shade treatments, and the intercellular CO2 concentration (C
i) had the opposite change trend. Under both shading conditions, the light saturation point, light compensation point and photon-saturated
photosynthetic rate (P
max) became lower than those under full sunlight, and it was the opposite for the apparent quantum yield (AQY). The higher the
level of shade, the lower the integrated daytime carbon gain, stomatal and epidermis cell densities, specific leaf mass (SLM),
bulb mass ratio (BMR), leaf thickness, and Chl a/b ratio. In contrast, contents of Chls per dry mass (DM), leaf area ratio (LAR), leaf mass ratio (LMR), leaf length, leaf area
and total leaf area per plant increased under the same shade levels to promote photon absorption and to compensate for the
lower radiant energy. Therefore, when the integrated daytime carbon gain, leaf area and total leaf area per plant, which are
the main factors determining the productivity of L. radiata var. radiata plant, were taken into account together, this species may be cultivated at about 60∼70% of ambient irradiance to promote
its growth. 相似文献
3.
Photosynthetic and growth characteristics of Mosla chinensis and M. scabra were compared at three irradiances similar to shaded forest understory, forest edge, and open land. At 25 % full ambient irradiance, M. chinensis and M. scabra had similar photosynthetic characteristics, but saturation irradiance, compensation irradiance, and apparent quantum yield of M. chinensis were higher than those of M. scabra at full ambient irradiance and 70 % full ambient irradiance. At the same irradiance treatment, specific leaf area and leaf area ratio of M. chinensis were lower than those of M. scabra. Photon-saturated photosynthetic rate and water use efficiency of M. chinensis, however, were not significantly higher than those of M. scabra, and the leaf area and total biomass were lower than those of M. scabra. As a sun-acclimated plant, the not enough high photosynthetic capacity and lower biomass accumulation may cause that M. chinensis has weak capability to extend its population and hence be concomitant in the community. 相似文献
4.
The combined effects of water stress (WS) and low irradiance (LI) on growth, photosynthesis, osmotic adjustment, and lipid
peroxidation were studied in dragon spruce (Picea asperata Mast.) seedlings grown under two water treatments (well watered, 100 % of field capacity, and water stressed, 30 % of field
capacity) and two irradiances (HI, 100 % of full sunlight and LI, 15 % of full sunlight). WS reduced growth, chlorophyll (Chl)
a and b contents, net photosynthetic rate, transpiration rate, stomatal conductance, and effective quantum yield of photosystem 2
(Y) but increased free proline and malondialdehyde contents. LI increased Chl contents and decreased Y, photochemical quenching (qP), and non-photochemical quenching (qN) under both water treatments. Hence the seedlings in the understory were more sensitive to drought than to LI. 相似文献
5.
Leaf mass per unit area (LMA), carbon and nitrogen contents, leaf construction cost, and photosynthetic capacity (P
max) of Adiantum reniforme var. sinensis, an endangered fern endemic to the Three Gorges region in southwest China, were compared in five populations differing in
habitat such as soil moisture and irradiance. The low soil moisture and high irradiance habitat population exhibited significantly
higher LMA, area-based leaf construction (CCA), and carbon content (CA), but lower leaf nitrogen content per unit dry mass (NM) than the other habitat populations. The high soil moisture and low irradiance habitat populations had the lowest CCA, but their cost/benefic ratios of CCA/P
max were similar to the medium soil moisture and irradiance habitat population due to their lower leaf P
max. Hence A. reniforme var. sinensis prefers partially shaded, moist but well-drained, slope habitats. Due to human activities, however, its main habitats now
are cliffs or steeply sloped bare rocks with poor and thin soil. The relatively high energy requirements and low photosynthetic
capacity in these habitats could limit the capability of the species in extending population or interspecific competition
and hence increase its endangerment. 相似文献
6.
In a glasshouse, Bemisia tabaci infestation largely reduced response of photosynthesis to irradiance and CO2 concentration of Mikania micrantha compared with the non-infested control (C) ones. The maximum irradiance-saturated photosynthetic rate (P
max) and saturation irradiance (SI) of the infested M. micrantha were only 21.3 % and 6.5 % of the C-plants, respectively. B. tabaci infestation led to the reduction of contents of chlorophyll and carotenoids in M. micrantha, which was accompanied with the decrease of actual photosystem 2 (PS2) efficiency (ΦPS2), efficiency of excitation energy capture by open PS2 reaction centres (Fv′/Fm′), electron transport rate (ETR), and photochemical quenching (qP). Moreover, superoxide dismutase and catalase activities significantly decreased while proline and glutathione contents significantly
increased in infested M. micrantha. Hence B. tabaci infestation not only induced direct damage of photosynthetic apparatus but also altered the antioxidant enzymes activities
in M. micrantha, which might as consequences accelerate senescence of this weed. 相似文献
7.
Wagner de Melo Ferreira Rogério M. Suzuki Rosete Pescador Rita de Cássia L. Figueiredo-Ribeiro Gilberto B. Kerbauy 《In vitro cellular & developmental biology. Plant》2011,47(3):420-427
In general, plant material grown in vitro has low photosynthetic ability to achieve positive carbon balances. Therefore, a continuous supply of carbohydrates from
the culture medium is required, and sucrose has been the most commonly used carbon source. In this paper, we investigate the
effects of different sucrose concentrations and the presence and absence of light on the endogenous levels of soluble carbohydrates
and starch as well as on the proliferation and growth of Dendrobium Second Love (Orchidaceae) in vitro. The possibility of using etiolated stem segments as a means for micropropagating this hybrid was also verified. The results
obtained indicated that the presence and absence of light and the sucrose concentrations used influenced the amounts of soluble
carbohydrates and starch and the proliferation of D. Second Love shoots and roots. An increase in sucrose concentration caused
a progressive increase in the amounts of total carbohydrates and starch. Under both light conditions, sucrose was the main
sugar found in the shoots followed by glucose and fructose. The addition of sucrose to the culture medium up to 2% and 4%
was advantageous to the number of shoots produced per explant and the root longitudinal growth in the presence and absence
of light, respectively. Shoot and root dry matter and the number of roots formed per explant increased as sucrose concentration
was raised up to 6% in both light treatments. The use of dark-grown shoot segments proved to be a useful and reliable alternative
for the micropropagation of this hybrid. 相似文献
8.
Photosynthetic rate (P
N), SPAD value, specific leaf area (SLA), flag leaf area (FLA), and nitrogen content (LN) of genus Oryza were investigated and their correlation was analyzed to assess some of the main photosynthetic traits among different species
in the genus Oryza. The results revealed wide variation in these traits. The species O. rufipogon and O. australiensis exhibited maximum photosynthetic rate. Comparison of different types of genomes (diploid: 2n=2x=24; tetraploid: 2n=4x=48)
and growth habit (shade- or sun-grown) showed the species of diploid (with genome symbol EE; 2n=2x=24) genomes, with perennial
and sun-grown species, had high apparent photosynthesis compared to others. The species with BB/BBCC, shade-grown and the
tetraploids showed high SPAD value, and the flag leaf in sun-grown species and diploids were thicker (low SLA) compared with
others. However, no significant difference could be noticed among the different types of genomes. Higher leaf area was noticed
among the species of CC/CCDD genome, perennial shade-grown species and tetraploids than in others. The variety IR 36 exhibited
highest leaf nitrogen concentration. Correlation analysis showed a strong relationship between P
N and leaf nitrogen concentration while no marked relationships were observed among other characteristics. It implies that
the species with thick and small leaves with high nitrogen concentration and high photosynthesis evolved better than others.
O. rufipogon, with the same genome as O. sativa, could be one of the wild rice resources for elite crop improvement. 相似文献
9.
Yan Bao Lei Yu Long Feng Yu Long Zheng Rui Fang Wang He De Gong Yi Ping Zhang 《Biological invasions》2011,13(12):2703-2714
Both innate and evolutionarily increased ecophysiological advantages can contribute to vigorous growth, and eventually to
invasiveness of alien plants. Little effort has been made to explore the roles of innate factors of alien plants in invasiveness
and the effects of CO2 enrichment on alien plant invasions. To address these problems, we compared invasive Eupatorium adenophorum, its native conspecific, and a native congener (E. japonicum) under ambient and doubled atmospheric CO2 concentrations. Native E. adenophorum from Mexico grew slower than invasive E. adenophorum but faster than native E. japonicum under both CO2 concentrations. The faster growth rate of invasive E. adenophorum was associated with higher photosynthetic capacity and leaf area ratio. For invasive E. adenophorum, the higher photosynthetic capacity was associated with higher nitrogen (N) allocation to photosynthesis, which was related
to lower leaf mass per area; the higher leaf area ratio was due to lower leaf mass per area and higher leaf mass fraction.
Tradeoff between N allocations to photosynthesis versus defenses was found. CO2 enrichment significantly increased relative growth rate and biomass accumulation by increasing actual photosynthetic rate
for all studied materials. However, the relative increase in growth was not significantly different among them. CO2 enrichment did not influence N allocation to photosynthesis, but increased N allocation to cell walls. The reduced leaf N
content decreased N content in photosynthesis, explaining the down-regulation of photosynthetic capacity under prolonged elevated
CO2 concentration. Our results indicate that both innate and evolutionary advantages in growth and related ecophysiological traits
contribute to invasiveness of invasive E. adenophorum, and CO2 enrichment may not aggravate E. adenophroum’s invasion in the future. 相似文献
10.
As common ragweed (Ambrosia
artemisiifolia L.) spreads across Europe and other regions, it is becoming both a health and an economic threat. To better understand which
environmental conditions facilitate the spread of the invasive species, in 2010, a greenhouse experiment was conducted determining
the effects of various nitrogen levels (10, 50 and 100 kg N/ha), soil moisture level (low and high) and competition levels
(no competition, medium competition and high competition) on the growth parameters of ragweed. Single-grown ragweed responded
favourably to the medium nitrogen and water increase, whereas the ragweed growth parameters in competition stands increased
only when high levels of nitrogen and water were added. High competition reduced the total dry matter of ragweed by up to
83%, but the ragweed continued to increase its relative growth rate during the full-flowering stage and allocate its dry matter
to reproductive parts, producing up to 70 seeds per plant. Ragweed is a poor competitor when there is high resource availability;
however, under disturbance and in the shortage of nutrients and water conditions, the intensity of competition decreases and
the ragweed performance is minimally affected. The addition of medium levels of nitrogen to promote the growth of competitive
species, prevention of disturbance and establishment of plant communities with stress-tolerant species is measures that should
help to prevent the further spread of ragweed. 相似文献
11.
In stream ecosystems, the growth of aquatic primary producers is affected by spatial and temporal variations in the riparian
canopy, which can influence the availability of light resources. Aquatic plants can acclimate to low light environments by
employing a suite of morphological or physiological mechanisms to increase light capture or photosynthetic efficiency. Some
species may also use alternate types of propagules to colonize environments with heterogeneous light environments. In a greenhouse
experiment we examined the morphological and physiological response of watercress (Nasturtium officinale R. Br.) to a gradient of increasing light levels, which ranged from 7% ambient light to full sunlight. We also determined
if watercress seedlings and vegetative fragments differed in their growth response to increasing light levels. Total biomass
and root biomass of seedlings and vegetative fragments decreased with decreasing light levels. The difference in plant biomass
across treatments was due to morphological changes in total canopy area and leaf area, both of which increased with decreasing
light levels. Seedlings and vegetative fragments did not differ in their response to light availability, but vegetative fragments
had higher final biomass as a result of higher initial biomass. Physiological acclimation to low light levels appears to be
of secondary importance for watercress as the concentrations of total chlorophyll, chlorophyll a, chlorophyll b, and chlorophyll a:b did not differ among light levels or between seedlings and vegetative fragments. Seedlings and vegetative fragments grown
under high light levels had a greater percentage of carbon and a lower percentage of nitrogen than plants grown under low
light conditions. The results of this study indicate that watercress displays considerable morphological plasticity and acclimates
to low light conditions primarily by increasing leaf area and canopy surface area. There is no evidence that the type of watercress
propagule (seedling vs. vegetative fragment) imparts any growth advantage in low light environments and watercress grown from
either type of propagule showed no differences in their morphological or physiological responses to varying light regimes.
Handling editor: S. M. Thomaz 相似文献
12.
Hosam O. Elansary 《Acta Physiologiae Plantarum》2017,39(7):145
The availability of sufficient irrigation water and the development of drought-tolerant species are challenging factors in the design and maintenance of green roofs in modern cities. Green roof plants of Petunia hybrid Headliner® Red Star, Ageratum hybrid Artist® blue, and Mentha spicata L. grown in a simulated green roof pot system under controlled greenhouse conditions. The plants were watered every 2 or 6 days (2DWI/6DWI) for 8 weeks accompanied by either a 6-day treatment of seaweed extracts of Ascophyllum nodosum as a soil drench or foliar spray, or two concentrations of trinexapac-ethyl (TE) biweekly sprays. Following treatments, leaf number, leaf area, dry weights, plant height, stomatal conductanse, photosynthetic and transpiration rates and leaf water potential and relative water content were determined in two seasons during 2016 and 2017. The prolonged irrigation intervals reduced plant growth as revealed by morphological and physiological parameters. The application of SWE as drench treatment improved Petunia and Ageratum plant vegetative growth, stomatal conductance, photosynthetic and transpiration rates and leaf water potential and relative water content during prolonged irrigation intervals. TE increased the vegetative growth as well as the physiological performance of Ageratum plants. However, neither SWE nor TE treatments improved the performance of Mentha plants under prolonged irrigation intervals. It was suggested that improved photosynthetic rates were stimulated by enhanced stomatal conductance leading to improved leaf water potential as well as increased relative water content during prolonged irrigation conditions. 相似文献
13.
DUF538 domain-containing protein family consists of several plant proteins of unknown functions. This protein family has already
been discovered by genome annotation tools and cloned as an inducible gene product under various environmental stress conditions.
For the first time, we presented a full length DUF538 cDNA (encoding 170 amino acid residues) clone, which was randomly isolated from Celosia cristata leaf cDNA library constructed under normal growth conditions and consistently amplified from leaf cDNA populations prepared
from nonstressed and drought-stressed leaves. We predicted that a DUF538 gene product can be a putative candidate for common stress-related protein (regulatory factor) in the plant system. The nucleotide
and deduced amino acid sequences of the isolated clone have been submitted to EMBL data bases under accession no. AJ535713. 相似文献
14.
Seedlings planted on degraded lands experience high leaf temperature in daytime because of the lack of vegetation shading.
The effect of high temperature on the photosynthetic capacity was investigated in Dipterocarpus obtusifolius Teijsm. ex Miq. and D. chartaceus Sym. seedlings planted on degraded sandy soils in southern Thailand. Neither species showed decrease in photosynthetic capacity
at leaf temperature over 38 °C as compared to that at 28 °C. D. obtusifolius showed higher photosynthetic capacity at high temperatures. Enhanced photosynthetic capacity at high temperatures would be
a key for high photosynthetic performance of D. obtusifolius planted on degraded sandy soils. 相似文献
15.
Helena T Funk Sabine Berg Karin Krupinska Uwe G Maier Kirsten Krause 《BMC plant biology》2007,7(1):45
Background
The holoparasitic plant genus Cuscuta comprises species with photosynthetic capacity and functional chloroplasts as well as achlorophyllous and intermediate forms with restricted photosynthetic activity and degenerated chloroplasts. Previous data indicated significant differences with respect to the plastid genome coding capacity in different Cuscuta species that could correlate with their photosynthetic activity. In order to shed light on the molecular changes accompanying the parasitic lifestyle, we sequenced the plastid chromosomes of the two species Cuscuta reflexa and Cuscuta gronovii. Both species are capable of performing photosynthesis, albeit with varying efficiencies. Together with the plastid genome of Epifagus virginiana, an achlorophyllous parasitic plant whose plastid genome has been sequenced, these species represent a series of progression towards total dependency on the host plant, ranging from reduced levels of photosynthesis in C. reflexa to a restricted photosynthetic activity and degenerated chloroplasts in C. gronovii to an achlorophyllous state in E. virginiana. 相似文献16.
Indeok Hwang Dilli Prasad Paudyal Seong-Ki Kim Hyeonsook Cheong 《Biotechnology and Bioprocess Engineering》2007,12(2):157-164
Inhibitors are very important in the study of hormone function. Brasinazole (Brz) is a specific inhibitor of brassinosteroids
(BRs) biosynthesis. To expand our knowledge of the molecular mechanisms of plant steroid signaling, we performed genetic screening
using medium containing Brz under dark conditions. Mutants insensitive to Brz developlonger hypocotyls than their wild type
counterparts. We isolatedabz453 as a Brz insensitive mutant. TAIL-PCR and the segregation ratio of T2 plants indicated a single T-DNA insertion at the 24-Sterol
C-methyltransferase (SMT2) gene in theabz453 mutant. Recapitulation for putative FCP serine phosphatase (FSP), the gene neighboringSMT2, indicated no significant phenotypes, but theSMT2 anti-sense (SMT2-AS) line developed longer hypocotyls than the wild type in medium containing Brz. Additionally, theSMT2-AS line displayed similar phenotypes to theabz453 line in soil including enhanced growth and smaller silique. Theabz453 andSMT2-AS mutants showed phenotypes similar to those of wild type in medium containing benzylaminopurine, pacrobutrazol and ACC (precursor
for ethylene) under dark conditions. However, when brassinolide (BL) dose response was observed, theabz453 andSMT2-AS lines showed higher sensitivity than wild type. Theabz453/det2 andabz453/bri1-119 double mutants showed enhanced growth compared to thedet2 andbri1-119 line under both dark and light conditions. Specially, in dark conditions double mutants displayed nearly 2- and 1.5-fold
longer hypocotyls thandet2 andbri1-119 plants. Brz insensitivity to theSMT2 knock-out mutant and phenotypes of double mutants indicate that not only do BRI1 and DET2 influence the BRs response, as
evidenced by hypocotyl elongation, but another sterol derived signals may also be affected in mutants, suggesting that another
pathway is involved in hypocotyl elongation due to SMT2. 相似文献
17.
Athyrium pachyphlebium C. is a popular ornamental fern with considerable shade tolerance. The aim of this study was to investigate how the mature
sporophytes acclimate to different light levels and to obtain an optimal light environment for their growth both in natural
forest canopy and in urban landscapes. Plant growth and morphology, photosynthetic light-response curves and chlorophyll (Chl)
fluorescence were measured at four different light levels (45% full sunlight, 30%, 20% and 8%). As the light intensities declined
from 45% to 20%, seedling height, crown growth, foliage number and plant lifespan increased significantly. Seedlings grown
at 20% light level were vigorous with great ornamental value. Plants grown in deep shade (8% light) showed severe symptoms
of lodging and in 45% full sun, the plants showed highlight-stress symptoms. Seedlings in high light levels exhibited a higher
light-saturated photosynthetic rate (P
max), light compensation point (LCP), light saturation point (LSP) and a reduced ability for nonphotochemical quenching (NPQ)
of excess light than those in low light levels. However, seedlings in low light exhibited greater efficiency in absorbing
and utilizing light energy, characterized by higher chlorophyll b (Chl b) and electron transport rate (ETR). These results indicated that a light level of about 20% full sun appeared to be optimal
for A. pachyphlebium when both physiological and morphological performance in the landscape were considered. 相似文献
18.
The effects of the availability of light (high, medium and low) and soil water (wet and dry) on morphological and physiological traits responsible for whole plant carbon gain and ramet biomass accumulation were examined in a splitter-type clonal herbaceous species Primula sieboldii, a spring plant inhabiting broad range of light environments including open grassland and oak forest understory. Growth experiments were conducted for three genets originated from natural microhabitats differing in light and soil water availability. Ramets of a genet from high light and wet microhabitat, which were grown in low light (relative photon flux density: R-PPFD of 5%) showed 41% less light-saturated photosynthetic rate, 50% less dark respiration rate and earlier defoliation than the ramets in high light (R-PPFD of 61%). The estimation of daily photosynthesis revealed that the light acclimation response in leaf gas exchange contributes to efficient carbon gain of whole plants, irrespective of experimental light conditions. Water stress increased root weight ratio, decreased ramet leaf area, petiole length and photosynthetic capacity. These morphological effects of water stress were larger in high and medium light regimes than in low light regime. The consequence of the above responses was recognized in the relative growth rate of the ramets. The relative growth rate of the ramets in high light with wet regime was four-fold of that in low light plus wet regime, and was 1.5-fold of that in high light plus dry regime. However, even in low light and/or dry regimes, ramets kept positive relative growth rates and produced gemma successfully. We could not detect significant variation in growth responses among genets. The high photosynthetic plasticity revealed in the present study should enable Primula sieboldii to inhabit in a broad range of light and soil water availability. 相似文献
19.
Eupatorium adenophorum is one of the more noxious invasive plants worldwide. However, the mechanisms underlying its invasiveness are still not well
elucidated. In this study, we compared the invader with its two native congeners (E. heterophyllum and E. japonicum) at four irradiances in terms of growth, biomass allocation, morphology, and photosynthesis. The higher light-saturated photosynthetic
rate (P
max) and total leaf area of the invader may contribute to its higher relative growth rate (RGR) and total biomass compared with
its native congeners. Total biomass and RGR increased significantly with the increase of P
max and total leaf area. The higher support organ mass fraction and the lower root mass fraction of the invader may also contribute
to its higher RGR and biomass through increasing carbon assimilation and reducing respiratory carbon loss, respectively. The
higher growth rate of the invader increased its total leaf area, ramet number, and crown area. These traits may help the invader
to form dense monoculture, outshading native plant species. However, consistently higher leaf area ratio, specific leaf area,
and leaf mass fraction were not found across irradiances for the invader compared with its native congeners. Higher plasticity
in response to irradiance was also not found for the invader. The invader retained advantages over the natives across irradiances,
while its performance decreased with lower irradiance. The results indicate that the invader may be one of the few super invaders.
Reducing irradiance may inhibit its invasions. 相似文献
20.
Leaf tissue damaging to seedlings can limit their subsequent growth, and the effects may be more extensive. Compensatory photosynthesis
responses of the remnant cotyledon and primary leaf of Pharbitis purpurea to clipping and the effect of clipping on seedling growth were evaluated in a pot-cultivated experiment. Three treatments
were conducted in the experiment, which were clipped cotyledon (CC), clipped second leaf (CL), and control group (CG). The
area, thickness, mass, and longevity of the remaining cotyledon of CC exhibited over-compensatory growth. In contrast, seedlings
of CC had under-compensatory growth in seedling height, root length, seedling mass, and root to shoot ratio. However, the
traits of remnant cotyledon and seedling in CL treatment exhibited equal-compensatory growth. Net photosynthetic rate of the
cotyledon of CC was significantly higher than those of CL and CG treatments, and the diurnal changes in photosynthetic rates
showed significantly different patterns which were unimodal curve (CC) and bimodal curve (CL and CG), respectively. There
was no significant difference between CL and CG treatment. Net photosynthetic rate of the primary leaf of CL was significantly
higher than that of CG treatment. However, the photosynthetic rates of primary leaves of CL and CG treatments showed similar
photosynthetic patterns characterized by a bimodal curve. P. purpurea seedlings used a compensatory growth strategy in the remaining cotyledon or the primary leaf to resist leaf loss and minimize
any adverse effects. 相似文献