Maternal environmental effects on the phenotypic responses of the twining vine Ipomoea purpurea to support availability

The presence of physical support elicits a number of morphological changes in the shoot of the common morning glory Ipomoea purpurea , including a shortening of internodes and petioles and a thickening of the main stem. Working with experimentally supported and non-supported plants of I . purpurea , I tested the existence of maternal environmental effects of physical support in this twining vine. I evaluated whether the offspring of supported plants differed from the offspring of non-supported plants in a number of morphological and reproductive characters. Stem diameter was the only shoot trait that showed a significant effect of the maternal environment (support). The stems of the progeny of supported mother plants were thicker than the stems of the progeny of non-supported mother plants. This was true for both supported and non-supported progeny. Stem diameter, however, was not significantly related to plant fitness (seed number) in supported or non-supported progeny plants. The maternal environment did not affect the magnitude of the phenotypic responses to support of shoot traits in the progeny plants. There were no maternal environmental effects of physical support on the proportion of flowering plants at week 10 in both non-supported and supported progeny. Likewise, the presence of physical support in the maternal environment did not affect reproductive traits (seed number, seed size, percentage of reproductive biomass) in supported and non-supported progeny plants. Finally, the relationship between seed size and seed number was affected by the maternal support environment. The progeny of supported mother plants showed a significantly negative association (trade-off) between seed size and number, whereas such a trade-off was not observed in the progeny of non-supported plants. This was true for both supported and non-supported progeny.     

Variation in growth form in relation to spectral light quality (red/far-red ratio) in Plantago lanceolata L. in sun and shade populations

Plants from a sun and shade population were grown in two environments differing in the ratio of red to far-red light (R/FR ratio). A low R/FR ratio, simulating vegetation shade, promoted the formation of long, upright-growing leaves and allocation towards shoot growth, whereas a high R/FR ratio had the opposite effects. The increase in plant height under the low R/FR ratio was accompanied by a reduction in the number of leaves. Population differences in growth form resembled the differences between plants grown in different light environments: plants from the shade population had rosettes with long erect leaves, whereas plants from the sun population formed prostrate rosettes with short leaves. Plants from the shade population were more responsive to the R/FR ratio than plants from the sun population: the increases in leaf length, plant height, and leaf area ratio under a low R/FR ratio were larger in the shade population. However, differences in plasticity were small compared to the population difference in growth form itself. We argue that plants do not respond optimally to shading and that developmental constraints might have limited the evolution of an optimal response. Received: 8 December 1996 / Accepted: 31 March 1997     

Reproductive success in varying light environments: direct and indirect effects of light on plants and pollinators

Plant populations often exist in spatially heterogeneous environments. Light level can directly affect plant reproductive success through resource availability or by altering pollinator behavior. It can also indirectly influence reproductive success by determining floral display size which may in turn influence pollinator attraction. We evaluated direct and indirect effects of light availability and measured phenotypic selection on phenological traits that may enhance pollen receipt in the insect-pollinated herb Campanulastrum americanum. In a natural population, plants in the sun had larger displays and received 7 times more visits than plants in the shade. Using experimental arrays to separate the direct effects of irradiance on insects from their response to display size, we found more visits to plants in the sun than in the shade, but no association between number of visits each flower received and display size. Plants in the sun were not pollen limited but pollen-augmented shade flowers produced 50% more seeds than open-pollinated flowers. Phenological traits, which may influence pollen receipt, were not under direct selection in the sun. However, earlier initiation and a longer duration of flowering were favored in the shade, which may enhance visitation in this pollen-limited habitat.     

Phenotypic integration may constrain phenotypic plasticity in plants

Phenotypic plasticity is essential for plant adaptation to changing environments but some factors limit its expression, causing plants to fail in producing the best phenotype for a given environment. Phenotypic integration refers to the pattern and magnitude of character correlations and it might play a role as an internal constraint to phenotypic plasticity. We tested the hypothesis that phenotypic integration – estimated as the number of significant phenotypic correlations between traits – constrains phenotypic plasticity of plants. The rationale is that, for any phenotypic trait, the more linked with other traits it is, the more limited is its range of variation. In the perennial species Convolvulus chilensis (Convolvulaceae) and Lippia alba (Verbenaceae) we determined the relationship between phenotypic plasticity to relevant environmental factors – shading for C. chilensis and drought for L. alba– and the magnitude of phenotypic integration of morphological and biomass allocation traits. In C. chilensis plants, plasticity to shading of a given trait decreased with the number of significant correlations that it had with the other traits. Likewise, the characters that showed greater plasticity to experimental drought in L. alba plants had fewer significant phenotypic correlations with other characters. We report a novel limit to phenotypic plasticity of plants by showing that the phenotypic trait architecture may constrain their plastic, functional responses to the environment.     

Effect of support availability,mother plant genotype and maternal support environment on the twining vine <Emphasis Type="Italic">Ipomoea purpurea</Emphasis>

In the twining vine Ipomoea purpurea we experimentally assessed the effect of support availability (a vertical stake), maternal genotype (family), and maternal environment (presence or absence of support in mother plants) on morphological traits, accounting for differences in initial seed size. While there was no effect of the maternal environment on seed size at the family level, families within each maternal environment did differ in seed size. Seeds from families of supported mothers showed higher germination than those from families of unsupported mothers. The maternal environment did not influence shoot traits but affected phenotypic plasticity in the number of leaves in response to support. Thus, whereas progeny plants from unsupported mothers did not show a response to support availability in the number of leaves, progeny from supported mother plants had a greater number of leaves once support was provided. The maternal genotype only affected the number of leaves.     

The functional ecology of shoot architecture in sun and shade plants of Heteromeles arbutifolia M. Roem., a Californian chaparral shrub

The functional roles of the contrasting morphologies of sun and shade shoots of the evergreen shrub Heteromeles arbutifolia were investigated in chaparral and understory habitats by applying a three-dimensional plant architecture simulation model, YPLANT. The simulations were shown to accurately predict the measured frequency distribution of photosynthetic photon flux density (PFD) on both the leaves and a horizontal surface in the open, and gave reasonably good agreement for the more complex light environment in the shade. The sun shoot architecture was orthotropic and characterized by steeply inclined (mean = 71^o) leaves in a spiral phyllotaxy with short internodes. This architecture resulted in relatively low light absorption efficiencies (E _A) for both diffuse and direct PFD, especially during the summer when solar elevation angles were high. Shade shoots were more plagiotropic with longer internodes and a pseudo-distichous phyllotaxis caused by bending of the petioles that positioned the leaves in a nearly horizontal plane (mean = 5^o). This shade-shoot architecture resulted in higher E _A values for both direct and diffuse PFD as compared to those of the sun shoots. Differences in E _A between sun and shade shoots and between summer and winter were related to differences in projection efficiencies as determined by leaf and solar angles, and by differences in self shading resulting from leaf overlap. The leaves exhibited photosynthetic acclimation to the sun and the shade, with the sun leaves having higher photosynthetic capacities per unit area, higher leaf mass per unit area and lower respiration rates per unit area than shade leaves. Despite having 7 times greater available PFD, sun shoots absorbed only 3 times more and had daily carbon gains only double of those of shade shoots. Simulations showed that sun and shade plants performed similarly in the open light environment, but that shade shoots substantially outperformed sun shoots in the shade light environment. The shoot architecture observed in sun plants appears to achieve an efficient compromise between maximizing carbon gain while minimizing the time that the leaf surfaces are exposed to PFDs in excess of those required for light saturation of photosynthesis and therefore potentially photoinhibitory. Received: 8 June 1997 / Accepted: 2 November 1997     

REACTION NORMS OF MORPHOLOGICAL AND LIFE-HISTORY TRAITS TO LIGHT AVAILABILITY IN IMPATIENS CAPENSIS

For plants, light availability is an important environmental factor that varies both within and between populations. Although the existence of sun and shade “ecotypes” is controversial, it is often assumed that trade-offs may exist between performance in sun and in shade. This study therefore investigated variation in reaction norms to light availability within and between two neighboring natural populations of the annual Impatiens capensis, one in full sun and the other in a forest understory. Seedlings were collected randomly from both populations and grown to maturity in a greenhouse under two light conditions: full light and 18% of full light. Selfed full-sib seed families were collected from plants from both populations grown in both parental light environments. To characterize family reaction norms, seedlings from each family were divided into the same two light treatments and individuals were scored for a variety of morphological and life-history traits. The maternal light environment had little impact on progeny reaction norms. However, the two study populations differed both qualitatively and quantitatively in plastic response to light availability (indicated by significant population x environment interactions in mixed-model ANCOVA). Much of this difference was attributable to population differences in light sensitivity of axillary meristem allocation patterns, which produced concurrent differences in reaction norms for a suite of developmentally linked traits. Within each population, different sets of traits displayed significant variation in plasticity (indicated by significant family x environment interactions). Thus, the genetic potential for evolutionary response to selection in heterogeneous light environments may differ dramatically between neighboring plant populations. Between-environment genetic correlations were largely positive in the woods population and positive or nonsignificant in the sun population; there was no evidence for performance trade-offs across environments or sun or shade “specialist” genotypes within either population. There was little evidence that population differences represented adaptive differentiation for sun or shade; rather, the results suggested the hypothesis of differential selection on patterns of meristem allocation caused by population differences in timing of mortality and intensity of competition.     

Ethylene is required in tobacco to successfully compete with proximate neighbours

Plants sense neighbours even before these cause a decrease in photosynthetic light availability. Light reflected by proximate neighbours signals a plant to adjust growth and development, in order to avoid suppression by neighbour plants. These phenotypic changes are known as the shade‐avoidance syndrome and include enhanced shoot elongation and more upright‐positioned leaves. In the present study it was shown that these shade‐avoidance traits in tobacco (Nicotiana tabacum) are also induced by low concentrations of ethylene. Furthermore, it was shown that transgenic plants, insensitive to ethylene, have a delayed appearance of shade‐avoidance traits. The increase in both leaf angles and stem elongation in response to neighbours are delayed in ethylene‐insensitive plants. These data show that ethylene is an important component in the regulation of neighbour‐induced, shade‐avoidance responses. Consequently, ethylene‐insensitive plants lose competition with wild‐type neighbours, demonstrating that sensing of ethylene is required for a plant to successfully compete for light.     

Genetic,phenotypic, and environmental correlations in black medic,Medicago lupulina L., grown in three different environments

We have investigated the relationship between phenotypic and genetic correlations among a large number of quantitative traits (36) in three different environments in order to determine their degree of disparity and whether phenotypic correlations could be substituted for their genetic counterparts whatever the environment. We also studied the influence of the environment on genetic and phenotypic correlations. Twenty accessions (full-sib families) ofMedicago luPulina were grown in three environments. In two of these two levels of environmental stress were generated by harvesting plants at flowering and by growing plants in competition with barley, respectively. A third environment, with no treatment, was used as a control with no stress. Average values of pod and shoot weight indicate that competition induces the highest level of stress. The genetic and phenotypic correlations among the 36 traits were compared. Significant phenotypic correlations were obtained easily, while there was no genetic variation for 1 or the 2 characters being correlated. The large positive correlation between the genetic and phenotypic correlation matrices indicated a good proportionality between genetic and phenotypic correlations matrices but not their similarity. In a given environment, when only those traits with a significant genetic variance were taken into account, there were still differences between genetic and phenotypic correlations, even when levels of significance for phenotypic correlations were lowered. Consequently, it is dangerous to substitute phenotypic correlations for genetic correlations. The number of traits that showed genetic variability increased with increasing environmental stress, consequently the number of significant genetic correlations also increased with increasing environmental stress. In contrast, the number of significant phenotypic correlations was not influnced by the environment. The structures of both phenotypic and genetic matrices, however, depended on the environment, and not in the same way for both matrices.     

匍匐茎草本金戴戴对盐分梯度的表型可塑性

 研究了匍匐茎型克隆草本金戴戴(Halerpestes ruthenica) 4种基株（基因型）对不同盐分处理（0,85.5, 171.0, 256.5和342.0 mM NaCl）的表型可塑性。随着盐分浓度的增加,实验植物与生长相关的性状指标 (如植株干重、总叶面积、分株数和总匍匐茎长度) 显著减小。植株干重、总叶面积和总匍匐茎长度具有显著的基株间差异。实验植物与形态相关的性状指标 (如平均叶柄长和根冠比) 对盐分梯度具有可塑性并具有显著的基株间差异;而其它形态指标 (如平均节间长、比节间长和比叶柄长)     

Quantitative trait loci affecting delta13C and response to differential water availibility in Arabidopsis thaliana

Phenotypic plasticity is an important response mechanism of plants to environmental heterogeneity. Here, we explored the genetic basis of plastic responses of Arabidopsis thaliana to water deficit by experimentally mapping quantitative trait loci (QTL) in two recombinant inbred populations (Cvi x Ler and Ler x Col). We detected genetic variation and significant genotype-by-environment interactions for many traits related to water use. We also mapped 26 QTL, including six for carbon isotope composition (delta13C). Negative genetic correlations between fruit length and fruit production as well as between flowering time and branch production were corroborated by QTL colocalization, suggesting these correlations are due to pleiotropy or physical linkage. Water-limited plants were more apically dominant with greater root:shoot ratios and higher delta13C (higher water-use efficiency) when compared to well-watered plants. Many of the QTL effects for these traits interacted significantly with the irrigation treatment, suggesting that the observed phenotypic plasticity is genetically based. We specifically searched for epistatic (QTL-QTL) interactions using a two-dimensional genome scan, which allowed us to detect epistasis regardless of additive genetic effects. We found several significant QTL-QTL interactions including three that exhibited environmental dependence. These results provide preliminary evidence for proposed genetic mechanisms underlying phenotypic plasticity.     

Could shading reduce the negative impacts of drought on coffee? A morphophysiological analysis

Based on indirect evidence, it was previously suggested that shading could attenuate the negative impacts of drought on coffee (Coffea arabica), a tropical crop species native to shady environments. A variety (47) of morphological and physiological traits were examined in plants grown in 30-l pots in either full sunlight or 85% shade for 8 months, after which a 4-month water shortage was implemented. Overall, the traits showed weak or negligible responses to the light × water interaction, explaining less than 10% of the total data variation. Only slight variations in biomass allocation were observed in the combined shade and drought treatment. Differences in relative growth rates were mainly associated with physiological and not with morphological adjustments. In high light, drought constrained the photosynthetic rate through stomatal limitations with no sign of apparent photoinhibition; in low light, such constraints were apparently linked to biochemical factors. Sun-grown plants displayed osmotic adjustments, decreased tissue elasticities and improved long-term water use efficiencies, especially under drought. Regardless of the water availability, higher concentrations of lipids, total phenols, total soluble sugars and lignin were found in high light compared to shade conditions, in contrast to the effects on cellulose and hemicellulose concentrations. Proline concentrations increased in water-deprived plants, particularly those grown under full sun. Phenotypic plasticity was much higher in response to the light than to the water supply. Overall, shading did not alleviate the negative impacts of drought on the coffee tree.     

Leaf damage induces twining in a climbing plant

Successful climbing by vines not only prevents shading by neighbouring vegetation, but also may place the vines beyond ground herbivores. Here we tested the hypothesis that herbivory might enhance climbing in a vine species, and that such induced climbing should be greater in the shade. We assessed field herbivory in climbing and prostrate ramets of the twining vine Convolvulus arvensis. We evaluated plant climbing after mechanical damage in a glasshouse under both sun and shade conditions, and determined whether control and damaged plants differed in growth rate or photosynthetic capacity. Plants experienced greater herbivory when growing prostrate than when climbing onto companion plants, in both an open habitat and a shaded understorey. Experimental plants increased their twining rate on a stake after suffering leaf damage, in both high- and low-light conditions, and this induced climbing was not coupled to an increase in growth rate. Increased photosynthesis was associated with enhanced twining rate only in the shade. Herbivory may be an ecological factor promoting the evolution of a climbing habit in plants.     

Phenotypic plasticity in rice: responses to fertilization and inoculation with arbuscular mycorrhizal fungi

Aims Changes in the phenotype of crops (phenotypic plasticity) are known to play an important role in determining responses to nutrient availability, with the direction and magnitude of plasticity of individual traits being crucial for grain yields. Our study analysed the direction, magnitude and hierarchy of plastic responses of yield-related traits (i.e. biomass allocation and yield components) of rice (Oryza sativa L.) to nutrient availability. We estimated the effect of inoculation with arbuscular mycorrhizal fungi (AMF) on these characteristics of phenotypic plasticity.Methods A field experiment was carried out in northeast China, providing rice with six NPK fertilizer levels with or without inoculation with Glomus mosseae. At maturity, we quantified biomass allocation traits (shoot:root ratio and panicle:shoot ratio) and yield component traits (panicle number per hill, spikelet number per panicle, percentage of filled spikelets and seed weight). We also assessed the direction of change in each trait and the magnitude of trait plasticity.Important findings In non-inoculated plants, we found that biomass allocation and seed-number traits (i.e. panicle number per hill, spikelet number per panicle and percentage of filled spikelets) responded to fertilization in the same direction, increasing with rising fertilization. Panicle formation was the most plastic trait, while seed mass was the least plastic trait. AMF inoculation nullified the relationship between most biomass allocation and seed-number traits (except for that between panicle:shoot ratio and the percentage of filled spikelets) but increased the magnitude of plasticity in biomass allocation traits without altering the hierarchy of traits' plasticity. These results underscore the importance of plasticity of yield-related traits per se, and the impact of AMF on plasticity, for maintaining rice yields under low fertilization regimes.     

Constraints on the evolution of phenotypic plasticity in the clonal plant Hydrocotyle vulgaris

The evolution of phenotypic plasticity of plant traits may be constrained by costs and limits. However, the precise constraints are still unclear for many traits under different ecological contexts. In a glasshouse experiment, we grew ramets of 12 genotypes of a clonal plant Hydrocotyle vulgaris under the control (full light and no flood), shade and flood conditions and tested the potential costs and limits of plasticity in 13 morphological and physiological traits in response to light availability and flood variation. In particular, we used multiple regression and correlation analyses to evaluate potential plasticity costs, developmental instability costs and developmental range limits of each trait. We detected significant costs of plasticity in specific petiole length and specific leaf area in response to shade under the full light condition and developmental range limits in specific internode length and intercellular CO₂ concentration in response to light availability variation. However, we did not observe significant costs or limits of plasticity in any of the 13 traits in response to flood variation. Our results suggest that the evolution of phenotypic plasticity in plant traits can be constrained by costs and limits, but such constraints may be infrequent and differ under different environmental contexts.     

Carotenoid composition in sun and shade leaves of plants with different life forms

The carotenoid composition of sun leaves of nine species of annual crop plants (some with several varieties) was compared with sun and shade leaves of several other groups of plants, among those sun and shade leaves of several species of perennial shrubs and vines and deep-shade leaves of seven rainforest species. All sun leaves contained considerably greater amounts of the components of the xanthophyll cycle violaxanthin, antheraxanthin and zeaxanthin as well as of β-carotene than the shade leaves, as had previously been reported for a variety of other species by Thayer & Björkman (Photosynthesis Research, 1990, 23, 331–343). Therefore, high light specifically stimulated β,β-carotenoid synthesis. The sun leaves of these crop species did not contain α-carotene which was, however, present in large amounts in all shade leaves and in smaller amounts in sun leaves of three of the four species of perennial shrubs and vines. There was no difference in neoxanthin content on a chlorophyll basis between sun and shade leaves, and there was no consistent general difference in the lutein content between all sun and all shade leaves. The zeaxanthin (and antheraxanthin) content at peak irradiance and the xanthophyll cycle pool size were compared for sun leaves from the different groups of plants with different life forms and different metabolic activities. When growing in full sunlight the annual crop species and a perennial mesophyte had high rates of photosynthesis whereas the perennial shrubs and vines had relatively low photosynthesis rates. More zeaxanthin (and antheraxanthin) were accumulated at noon in full sunlight in those species with the lower photosynthesis rates. However, it was not such that those species also possessed the larger pools of violaxanthin + antheraxanthin + zeaxanthin. Instead, the xanthophyll cycle pools of sun leaves of the annual crop species and the perennial mesophyte were not smaller, and were even possibly larger, than those of sun leaves of the perennial shrubs and vines with low photosynthesis rates. This was so in spite of the fact that the crop species experienced much lesser degrees of excessive light at full sun than the shrubs and vines. Thus, many of the crop species converted only about 30–50% of their xanthophyll cycle pool to zeaxanthin at noon, whereas the shrubs and vines typically converted more than 80% of their pool into zeaxanthin. The crop species also had larger pools of β-carotene than the shrubs and vines but smaller pools of lutein than the majority of the latter species.     

Costs versus risks: Architectural changes with changing light quantity and quality in saplings of temperate rainforest trees of different shade tolerance

Light requirements and functional strategies of plants to cope with light heterogeneity in the field have a strong influence on community structure and dynamics. Shade intolerant plants often show a shade avoidance strategy involving a phytochrome‐mediated stem elongation in response to changes in red : far red ratio, while shade‐tolerant plants typically harvest light very efficiently. We measured plant size, stem diameter, internode and leaf lengths in randomly chosen saplings of 11 woody species differing in their shade tolerance in both a secondary forest and an old‐growth temperate evergreen rainforest in southern Chile. We also recorded the irradiance spectrum and the diffuse and direct light availabilities at each sampling point. Significant differences were found for the mean light environment of the saplings of each species, which also differed in basal stem diameter, internode length and leaf length, but not in plant height. Both plant slenderness (plant height/stem diameter) and mean internode length increased with increasing light availability, but no relationship was found between any of these two traits and red : far red ratio. The change in plant slenderness with light availability was of lesser magnitude with increasing shade tolerance of the species, while internode change with light availability increased with increasing shade tolerance of the species. Shade tolerators afford higher costs (thicker stems and plants), which render more biomechanically robust plants, and respond more to the light environment in a trait strongly influencing light interception (internode length) than shade intolerant species. By contrast, less shade‐tolerant plants afforded higher risks with a plastic response to escape from the understorey by making thinner plants that were biomechanically weaker and poorer light interceptors. Thus, species differing in their shade tolerances do differ in their plastic responses to light. Our results contribute to explain plant coexistence in heterogeneous light environments by improving our mechanistic understanding of species responses to light.     

Specialist Insect Herbivore and Light Availability Do Not Interact in the Evolution of an Invasive Plant

Release from specialist insect herbivores may allow invasive plants to evolve traits associated with decreased resistance and increased competitive ability. Given that there may be genetic trade-off between resistance and tolerance, invasive plants could also become more tolerant to herbivores. Although it is widely acknowledged that light availability affects tolerance to herbivores, little information is available for whether the effect of light availability on tolerance differ between the introduced and native populations. We conducted a common garden experiment in the introduced range of Alternanthera philoxeroides using ten invasive US and ten native Argentinean populations at two levels of light availability and in the presence or absence of a specialist stem-boring insect Agasicles hygrophila. Plant biomass (total and storage root biomass), two allocation traits (root/shoot ratio and branch intensity, branches biomass/main stem biomass) and two functional traits (specific stem length and specific leaf area), which are potentially associated with herbivore resistance and light capture, were measured. Overall, we found that A. philoxeroides from introduced ranges had comparable biomass and tolerance to specialist herbivores, lower branch intensity, lower specific stem length and specific leaf area. Moreover, introduced populations displayed higher shade tolerance of storage root biomass and lower plastic response to shading in specific stem length. Finally, light availability had no significant effect on evolution of tolerance to specialist herbivores of A. philoxeroides. Our results suggest that post-introduction evolution might have occurred in A. philoxeroides. While light availability did not influence the evolution of tolerance to specialist herbivores, increased shade tolerance and release from specialist insects might have contributed to the successful invasion of A. philoxeroides.     

Adaptive plasticity in response to light and nutrient availability in the clonal plant Duchesnea indica

克隆植物蛇莓对光照强度和养分条件的适应性可塑性 表型可塑性可帮助植物缓冲环境压力并使其表型与当地环境相匹配,但目前仅少数性状的可塑性被广泛认为是适应性的。为充分理解可塑性的适应性意义,仍需进一步研究更多的植物功能性状及其环境因子。本研究将匍匐茎克隆植物蛇莓(Duchesnea indica)的21个基因型种植于不同的光照和养分条件下,并利用选择梯度分析检测了形态和生理可塑性对光照强度和养分有效性变化的适应性值。在遮荫条件下,蛇莓适合度(果实数、分株数和生物量)降低,节间缩短变细,成熟叶叶绿素含量降低,但叶柄长度、比叶面积、老叶叶绿素含量均增加。在低养分条件下,植株叶柄缩短,叶面积缩小变厚,叶绿素含量降低,但果实数量和根冠比增加。选择梯度分析表明,叶柄长度和老叶叶绿素含量对光照变化的可塑性是适应性的,老叶和成熟叶叶绿素含量对养分变化的可塑性也是适应性的。因此,不同性状的可塑性适应值取决于特定的生态背景。该研究的发现有助于理解克隆植物表型可塑性响应环境变化的适应性意义。     

Relationship between peroxidase activity and flower localization alongVanilla planifolia vines

Decapitated pending vines are the most responsive parts of vanilla plants. Inflorescence localization along training vines showed a decreasing gradient from the decapitated end to the base in sun locality and was irregular and showed opposite gradient in shade locality. Soluble and ionic peroxidase activities, determined in the leaves and in the internodes, showed a marked peak during the end of June and a gradient along training vines which was inverse to the gradient of inflorescence localization and opposite between sun or shade conditions, supporting the utility of peroxidases as spatial and temporal biochemical markers of flowering processes.