Plant Morphological Traits Research Articles

Path analysis suggests phytoene accumulation is the key step limiting the carotenoid pathway in white carrot roots

Two F2 carrot (Daucus carota L.) populations (orange rooted Brasilia x very dark orange rooted High Carotene Mass - HCM cross and the dark orange rooted cultivated variety B493 x white rooted wild carrot Queen Anne's Lace - QAL cross) with very unrelated genetic backgrounds were used to investigate intrinsic factors limiting carotenoid accumulation in carrots by applying phenotypic correlation and path analysis to study the relationships between major root carotenes, root color and several other morphological traits. Most of the correlations between traits were close and agreed in sign between the two populations. Root weight had a moderate to highly significant positive correlation with leaf length, root length and top and middle root diameter. Although phenotypic correlations failed to identify the order of the substrates and products in the carotenoid pathway the correct order of substrates and products (phytoene -> zeta-carotene -> lycopene) was identified in the causal diagram of beta-carotene for the Brasilia x HCM population. Path analysis of beta-carotene synthesis in the B493 x QAL population suggested that selection for root carotenes had little effect on plant morphological traits. Causal model of beta-carotene and lycopene in the B493 x QAL population suggested that phytoene synthesis is the key step limiting the carotenoid pathway in white carrots. Path analysis, first presented by Sewall Wright to study quantitative traits, appears to be a powerful statistical approach for the identification of key compounds in complex pathways.

Genetic variation in five populations of strawberry clover (Trifolium fragiferum cv. Palestine) in Western Australia

Genetic variation within and among populations of an outcrossing stoloniferous perennial legume, strawberry clover (Trifolium fragiferum L.), was studied using seed collected from 5 different locations in Western Australia. The sites ranged from Badgingarra to the north of the wheatbelt to Karridale in the southwest of the state. Seed was collected randomly at each site and was grown out at the University of Western Australia Field Station at Shenton Park, Perth. Thirteen morphological plant traits were measured and analysed. Results show that within-population variation was extremely high. In contrast, among-population variation was generally low with most characters showing only 8–15% of the total variation. Despite this, all but 1 of the measured plant traits differed among populations. Principal components analysis highlighted the large amount of variation within the populations with the first 3 principal components accounting for only 59% of the total variation. We suggest that the populations have begun to differentiate into ecotypes more suited to those habitats into which they have been sown but that within-population variation remains high due to the outcrossing nature of strawberry clover.

Morphological acclimation of aquatic Littorella uniflora to sediment CO2 concentration and wave exposure

Summary Species of the isoetid life form have many physiological, anatomical and morphological traits that can be seen as adaptations to the environmental characteristics of softwater lakes. Among these, dependence on CO2 from the interstitial water for photosynthesis is one of the more distinctive. To assess the impact of environmental conditions on morphology and resource allocation of Littorella uniflora (L.) Ascherson, and to test whether CO2 supply from the sediment constrains the maximum attainable leaf length of these plants, a suite of morphological plant traits were measured along a gradient of sediment CO2 availability. The sediment CO2 gradient (0·4–7 mol CO2 m−3 interstitial water) was obtained by collecting specimen from 13 Faroese lakes. Along the CO2 gradient, the maximum leaf length of the plants more than doubled and was significantly correlated to sediment CO2 concentration. In addition to leaf length, plant size, leaf number and below : above‐ground biomass ratio were also correlated with sediment CO2 concentration, whereas only weak or no correlations between wave exposure and morphological features of the plants were found. Likewise, no correlation between the nutrient status of the plants and morphology was observed. The results obtained emphasize the importance of sediment CO2 for the performance of L. uniflora and support the suggestion that the maximum attainable leaf length of these plants is set by the CO2 concentration in the interstitial water.

Eastern Bottlebrush Grass Yield, Persistence, and Nutritive Value in the Northeastern USA

Jensen, 1996). Virginia wildrye (Elymus virginicus L.) has been evaluated in the northeastern USA in terms Introduced (nonnative) species account for nearly all of the forage of yield, persistence, and nutritive value (Sanderson et grassesusedinnortheasternUSAforagesystems.Weevaluatedaccesal., 2004a, 2004b). Virginia wildrye performed better on sions of the native cool-season species, Eastern bottlebrush grass (Elymus hystrix var. hystrix L.), from the northeastern USA for yield, a deep soil in New York compared with shallow or persistence, plant morphological traits, and nutritive value. Thirteen sandy soils in Pennsylvania and Maryland, respectively. accessions and one commercial ecotype of bottlebrush grass were The nutritive value of Virginia wildrye was comparable transplanted into single-row field plots in late summer of 2000 at to that of orchardgrass; however, orchardgrass was much Beltsville, MD, Rock Springs, PA, and Big Flats, NY. Two orchardgrass more productive and persistent. (Dactylis glomerata L.) cultivars were included for reference. Yield, There is a need for more information on the usepersistence, morphology (leaf width, length, mass, area, and tillers fulness of locally adapted native grasses in production, per plant), and nutritive value data were collected during 2001 and conservation, and other plantings in the northeastern 2002. Bottlebrush grass was eliminated by the bluegrass billbug (SpheUSA. Therefore, we evaluated several northeastern colnophorus parvulus Gyllenhal) at Rock Springs in spring of 2001. At lections of bottlebrush grass for dry matter yield, persisBig Flats and Beltsville, the bottlebrush grass accessions produced as much dry matter per plant as the commercial ecotype. Orchardgrass tence, morphological characteristics, and nutritive value yielded four times as much dry matter as the mean of all bottlebrush at three locations. grass entries(102 g vs.26 g per plantaveraged for yearsand locations). The low productivity of bottlebrush grass resulted from reduced tillerMATERIALS AND METHODS ing especially during regrowth. There was very little regrowth of The experiment was conducted at the USDA-NRCS Plant bottlebrush grass during late summer in all environments. Survival Materials Center in Big Flats, NY (42N, 7654W, elevation of bottlebrush grass was 36% during 3 yr vs. 84% for orchardgrass. 290 m), the Russell E. Larson Agricultural Research Center Differences in nutritive value among accessions were due mainly to at Rock Springs, PA (4048N, 7752W, elevation 365 m), differences in leaf-to-stem mass ratio. Eastern bottlebrush grass has and the USDA-NRCS National Plant Materials Center in limited potential for use as a forage grass in the northeastern USA. Beltsville, MD (3902N, 7656W, elevation 36 m) from 2000 to 2002. Soil types were Unadilla silt loam (coarse-silty, mixed, active, mesic Typic Dystrudepts) at Big Flats, Hagerstown silt

Virginia Wildrye Evaluated as a Potential Native Cool‐Season Forage in the Northeast USA

Most forage grasses grown in the northeastern USA are introduced species. Interest in native plant species for conservation and production has increased because of new federal policies. We evaluated northeastern accessions of the native cool‐season grass Virginia wildrye (Elymus virginicus L.) for yield, persistence, and plant morphological traits. Thirteen accessions, one cultivar (Omaha), and one commercial ecotype of Elymus were transplanted into single‐row field plots in late summer of 2000 at Beltsville, MD, Rock Springs, PA, and Big Flats, NY. Two orchardgrass (Dactylis glomerata L.) cultivars were the checks. Yield and morphology (leaf width, length, mass, area, and tillers per plant) data were collected during 2001 and 2002. The Elymus accessions produced as much dry matter (28–57 g per plant) as the cultivar and commercial ecotype. Orchardgrass yielded more than twice as much dry matter than the mean of all Elymus entries (94 vs. 34 g per plant averaged for years and locations). The difference in productivity was related to reduced tillering in Elymus especially during regrowth. Yield per plant was strongly correlated (r = 0.62–0.81, P < 0.01) with the number of tillers per plant. Differences in productivity were also reflected in leaf blade traits, with Elymus having a lower leaf area and mass than orchardgrass. Leaf traits were positively correlated (r = 0.35–0.56, P < 0.05) with plant yield. Some northeastern Elymus accessions would probably perform as well as the commercial sources of Elymus in conservation plantings.

Relationship Between Plant Morphological Traits and Resistance to Sclerotinia minor in Lettuce

A low to moderate incidence of lettuce drop caused by Sclerotinia minor is commonly observed in commercial lettuce fields of all types of lettuce (e.g. crisphead, romaine, leaf, butter) and although partial resistance has been reported, no sources of immunity have been described. We sought to determine whether there was variability between different types of lettuce and among cultivars within types. Replicated experiments were conducted in an infested field using established inoculation procedures. Significant variation in susceptibility to S. minor was detected among cultivars within as well as between major lettuce types. Correlations between lettuce drop susceptibility and plant canopy size, seedling vigor, and additional morphological traits were determined. Variability between different field experiments was also evaluated for several traits and a subset of cultivars. Our results suggest that cultivated germplasm may provide genes that are as useful or more useful than those found in genotypes with more primitive growth habits in developing cultivars with tolerance to lettuce drop.

Nutritive Value of Virginia Wildrye, a Cool‐Season Grass Native to the Northeast USA

Interest in native plant species for conservation and production has increased because of new federal policies. We evaluated accessions of the native cool‐season grass Virginia wildrye (Elymus virginicus L.) from the northeastern USA for nutritive value and its association with plant morphological traits. Thirteen accessions, one cultivar (Omaha), and one commercial ecotype of Elymus were transplanted into single‐row field plots in late summer of 2000 at Beltsville, MD, Rock Springs, PA, and Big Flats, NY. Two orchardgrass (Dactylis glomerata L.) cultivars were included. Primary growth was harvested in April (Beltsville) or May (Rock Springs and Big Flats) of 2001 and 2002 and analyzed for neutral detergent fiber (NDF), crude protein (CP), and digestible NDF (dNDF). Nutritive value measures were related to plant morphological attributes [leaf width, length, area, and leaf‐to‐stem mass ratio (LSR)]. Virginia wildrye accessions differed (P < 0.01) in nutritive value and often had lower NDF and higher CP and dNDF than the commercial ecotype, Omaha cultivar, and orchardgrass. The LSR accounted for most of the variation in nutritive value. Orchardgrass was more mature at harvest than Elymus entries and thus lower in nutritive value. Neutral detergent fiber was negatively correlated with LSR (r = −0.26 to −0.74, P < 0.05), whereas CP and dNDF were positively correlated (r = 0.36 to 0.80 for CP and 0.44 to 0.74 for dNDF, P < 0.05). Neutral detergent fiber was also positively correlated (r = 0.27 to 0.86, P < 0.05) with leaf length. Virginia wildrye is comparable to other cool‐season grasses in nutritive value.

Relationships between plant traits and climate in the Mediterranean region: A pollen data analysis

Abstract:Question: What are the correlations between the degree of drought stress and temperature, and the adoption of specific adaptive strategies by plants in the Mediterranean region?Location: 602 sites across the Mediterranean region.Method: We considered 12 plant morphological and phenological traits, and measured their abundance at the sites as trait scores obtained from pollen percentages. We conducted stepwise regression analyses of trait scores as a function of plant available moisture (α) and winter temperature (MTCO).Results: Patterns in the abundance for the plant traits we considered are clearly determined by α, MTCO or a combination of both. In addition, trends in leaf size, texture, thickness, pubescence and aromatic leaves and other plant level traits such as thorniness and aphylly, vary according to the life form (tree, shrub, forb), the leaf type (broad, needle) and phenology (evergreen, summer‐green).Conclusions: Despite conducting this study based on pollen data we have identified ecologically plausible trends in the abundance of traits along climatic gradients. Plant traits other than the usual life form, leaf type and leaf phenology carry strong climatic signals. Generally, combinations of plant traits are more climatically diagnostic than individual traits. The qualitative and quantitative relationships between plant traits and climate parameters established here will help to provide an improved basis for modelling the impact of climate changes on vegetation and form a starting point for a global analysis of pollen‐climate relationships.

Relationships between plant traits and climate in the Mediterranean region: A pollen data analysis

Question: What are the correlations between the degree of drought stress and temperature, and the adoption of specific adaptive strategies by plants in the Mediterranean region? Location: 602 sites across the Mediterranean region. Method: We considered 12 plant morphological and phenological traits, and measured their abundance at the sites as trait scores obtained from pollen percentages. We conducted stepwise regression analyses of trait scores as a function of plant available moisture (α) and winter temperature (MTCO). Results: Patterns in the abundance for the plant traits we considered are clearly determined by α, MTCO or a combination of both. In addition, trends in leaf size, texture, thickness, pubescence and aromatic leaves and other plant level traits such as thorniness and aphylly, vary according to the life form (tree, shrub, forb), the leaf type (broad, needle) and phenology (evergreen, summer-green). Conclusions: Despite conducting this study based on pollen data we have identified ecologically plausible trends in the abundance of traits along climatic gradients. Plant traits other than the usual life form, leaf type and leaf phenology carry strong climatic signals. Generally, combinations of plant traits are more climatically diagnostic than individual traits. The qualitative and quantitative relationships between plant traits and climate parameters established here will help to provide an improved basis for modelling the impact of climate changes on vegetation and form a starting point for a global analysis of pollen-climate relationships. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Comparison of local and exotic maize varieties for stalk lodging components in a desert climate

A 2-year study on the influence of certain plant morphological traits as well as the chemical composition of the stalk on lodging in exotic and local maize groups was done at Sultan Qaboos University. The exotic group consisted of six varieties, while five varieties were represented in the local group. The soil type was classified as saline, the EC being 3.9–4.2 dS/m. In both maize groups, lodging was negatively correlated with grain yield, rind thickness and stalk breaking strength. Weight of 5-cm stalk section was negatively correlated with lodging in the local group but the exotic group showed no such correlation. In the exotic group, lodging was positively correlated with ear height and negatively correlated with stalk lignin and total nonstructural carbohydrate (TNC) concentration but no such correlations were represented in the local group. In a stepwise regression analysis, a four-variable model consisting of shelling percentage, stalk breaking strength, rind thickness and TNC had a coefficient of determination ( R 2) of 0.66, suggesting that 66% of the variability in lodging was due to variability in these characters acting together. Based on this result it was suggested that, in breeding for lodging resistance in maize in a desert climate, it may be worthwhile to focus on these four parameters.

Morphometric parameters: an approach for the indication of environmental conditions on calcareous grassland

Morphological traits of plants often vary considerably in response to different environmental conditions, which may render them suitable as sensible indicators for conservation purpose. To compare the plasticity of morphological traits of species of calcareous grassland under different environmental conditions (stands of different structure with respect to litter and vegetation height), morphometric investigations were carried out on calcareous grasslands differing in grazing regime. Populations of the calcareous grassland species Plantago media and Scabiosa columbaria subject to different grazing regimes showed considerable plasticity. There were, e.g. relationships between shoot height, biomass, and fertility of individuals. Shoot height and the number of diaspores per inflorescence increased significantly with increasing cover of litter. Simultaneously there were considerable changes in the reproductive mode, from generative only to a combination of generative and vegetative reproduction. The analysis of morphological plasticity showed that different environmental conditions could accurately and easily be monitored through the species-specific growth response. Especially shoot height appears to play a central role, since the study species can vary this growth parameter to escape light deficiency of tall stands rich in litter. Due to its large variability, shoot height can be used as an indicator of growth conditions of the studied populations that are closely linked to land use and conservation management.

Combining ability and patterns of inheritance for plant and fruit traits in Japanese quince (Chaenomeles japonica)

Phenotypic variation and pattern ofinheritance was investigated for plant andfruit traits in Japanese quince (Chaenomeles japonica, Maloideae). Japanesequince is a minor fruit crop in Latvia andLithuania, and is presently being developedfor production of juice, aroma and fruitfibre in Sweden and Finland. General andspecific combining ability was estimatedfor five plant vegetative traits, eightfruit yield and morphology traits, and fivefruit biochemistry traits in a studypopulation consisting of 14 hybridfamilies. Thorniness seems to be controlledprimarily by a single locus. All othertraits studied appear to be governedprimarily by additive genes, as judged fromgeneral combining ability estimates.Significant specific combining ability(SCA) was detected for yield, plant heightand some fruit traits. However, therelative contribution of SCA to the overallgenetic variance was in general low. Anefficient breeding strategy for Japanesequince could therefore be based onrecurrent selection.

Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

Pattern and process in Norwegian upland grasslands: a functional analysis

Abstract. Four classes of functional and morphological plant traits – established strategies (the CSR scheme sensu Grime 1979), life‐forms (sensu Raunkiaer 1934), morphology, and regenerative strategies – are used as tools for explaining vegetation gradients at summer farms in the mountains of western Norway. These farms are assembly points for free‐ranging domestic grazers, and differ floristically and ecologically from the surrounding heath or woodland vegetation. DCA and TWINSPAN are used to relate major gradients in a floristic data set from 12 summer farms to two sets of explanatory variables: (1) environmental variables representing physical factors, plot position, soils, and land use, and (2) the 4 classification schemes. The main floristic gradient parallels a spatial gradient from the centres of the farms to the surrounding vegetation. A functional interpretation based on the concurrent use of the 2 sets of explanatory variables suggests that the gradient is one of decreasing disturbance and increasing environmental stress caused by decreasing grazing and manure effects away from farms. Partial CCA is used to investigate the relationships between the 4 functional/morphological plant trait classes. The 4 classification schemes are partially redundant, and do not represent different trends of specialization within the landscape. There is no strong evidence for decoupling of the traits of the vegetative and regenerative phases within the data. The combination of general process‐based theories and specific plant attribute responses enhances the generality and interpretability of the study.

Pattern and process in Norwegian upland grasslands: a functional analysis

Abstract Four classes of functional and morphological plant traits – established strategies (the CSR scheme sensu Grime 1979), life‐forms (sensu Raunkiaer 1934), morphology, and regenerative strategies – are used as tools for explaining vegetation gradients at summer farms in the mountains of western Norway. These farms are assembly points for free‐ranging domestic grazers, and differ floristically and ecologically from the surrounding heath or woodland vegetation. DCA and TWINSPAN are used to relate major gradients in a floristic data set from 12 summer farms to two sets of explanatory variables: (1) environmental variables representing physical factors, plot position, soils, and land use, and (2) the 4 classification schemes. The main floristic gradient parallels a spatial gradient from the centres of the farms to the surrounding vegetation. A functional interpretation based on the concurrent use of the 2 sets of explanatory variables suggests that the gradient is one of decreasing disturbance and incre...

Characteristics and the yield potential of different pepino accessions

Pepino (Solanum muricatum) is a small herbaceous perennial minor fruit cum vegetable crop with multiple possibilities for consumption. Special features include its high yield potential, casy propagation by stem cuttings, perennial nature, fast growing and high response to intensive cultivation and fertilizer application and above all the habit of flowering and fruit set round the year. As on date 9 promising accessions have been established based on plant and fruit morphology, yield performance and quality traits. These accessions also offered differing preference for different utilities such as dessert fruit, squash etc.

Diversity in seed quality traits of common bean populations from Basilicata (Southern Italy)

AbstractThe diversity of nutritional and culinary traits in 21 populations of common bean from the Basilicata region was studied for three consecutive harvests (1995‐97). The results were compared with the six commercial cultivars widely grown in the region. Some populations deserve particular attention since they had large seeds, high protein content, low trypsin inhibitor levels and short cooking time. The cluster analysis showed that 18 populations clustered in two main groups and that the bush populations were clearly distinguishable from the climbing ones. When phaseolin type and some plant morphological traits were added to the nutritional and culinary traits to classify these populations, it was observed that they resembled the race Peru (Andean gene pool).

Genetic control of domestication traits in pearl millet (Pennisetum glaucum L., Poaceae)

Quantitative trait loci (QTLs) controlling the morphological differences between pearl millet (Pennisetum glaucum ssp. glaucum) and its wild ancestor (Pennisetum glaucum ssp. monodii, form mollissimum) were investigated in a cultivated/wild F2 population by means of RFLP markers. The most critical adaptive changes resulting from the domestication process involved the spikelet structure: non-shedding seeds with reduced bracts and bristles and long involucral pedicel. Major differences also concerned characters describing the plant architecture, phenology and spike sizes. Many morphological differences could be attributed to the effect of a small number of loci with relatively large effects. These loci are mainly concentrated on four linkage groups (2, 5, 6 and 7). The loss of shedding ability, due to the absence of a functional abscission layer, is controlled by a single locus on linkage group 6 (al6). Genetic control of the other spikelet traits involved factors with large effects which are located in the region of linkage group 6 close to al6 and to an esterase gene, Esterase-E. Moreover, QTLs with large effects on plant and spike morphology traits such as plant height, number of spikes and weight of the spike were also mapped on linkage groups 6 and 7. This strong linkage of factors in the domestication syndrome may be involved in the maintenance of the phenotypic identity of wild and cultivated populations in sympatry. This result also brings new arguments in the understanding of the domestication process of this allogamous crop.

Binding of FGF-5 and FGFR-4 that express transiently in the rat cerebellar cortex during postnatal development

Global climate change is expected to have impacts on the physiological, phenological, and morphological traits of plants. However, the vulnerability of tropical plant reproductive processes in response to climate change events has been poorly studied. Here, we assess if warming and elevated CO2 compromise the pollen characteristics of Stylosanthes capitata Vogel, a tropical legume forage species. This work was conducted in a Trop-T-FACE (combined Free-Air Temperature Controlled Enhancement and Free-Air Carbon Dioxide Enrichment) facility, where we exposed the plants to four treatments: C (Control-ambient atmospheric carbon dioxide concentration [CO2] and ambient temperature); eCO2 (increase in [CO2] to 600 ppm and ambient temperature); eT (canopy temperature increase by 2°C and ambient [CO2]); and eCO2+eT, a combination of both treatments. We analyzed pollen morphology of samples taken from the different treatments through light microscopy (LM) and scanning electron microscopy (SEM). In addition, pollen viability was analyzed through colorimetry. Based on the histological LM analysis, the tapetum cells of pollen sacs showed early degeneration under eT (72%) added to hypertrophy under eCO2 (67%) and eCO2+eT (90%) treatments. SEM images showed compaction of pollen exine and less distinguishable pollen apertures in the treated plots (eCO2, eT, and eCO2+eT), possibly, by the early death of the tapetum cells. These morphological abnormalities may hinder the viability of pollen grains, as observed especially in the eCO2+eT treatment (%V=64%) that was the lowest in comparison with the Control (71%) and the other treatments (eCO2 = 69%, eT = 67%). These results indicate that during the reproductive cycle of S. capitata pollen sacs and pollen grains are vulnerable to warming, elevated CO2, and their combined effects.

Intraspecific variation in salt tolerance and morphology in the coastal grass spartina patens (poaceae)

Clones of Spartina patens were collected from 19 locations throughout Gulf coast marshes of Texas, Louisiana, and Florida. Following three vegetative generations of de‐acclimation from field conditions, genotypes were subjected to a salinity screening protocol in which salinity was increased in weekly increments of 5‰ (gram salt/kilogram solution). Plants were harvested when there was 50% death of aboveground tissue, which we defined as the lethal salinity level. The genotypes displayed highly significant intraspecific variation in lethal salinity level, which ranged from 63‰ to 93‰. Significant intraspecific variation was also observed in all plant morphological variables, as well as leaf rolling, leaf expansion rates at 2‰ and 20‰ salinity, aboveground, belowground, and total biomass, and belowground‐to‐aboveground biomass ratio. An ANOVA of principal component scores from a PCA of lethal salinity level and covariable‐adjusted total plant dry mass further illustrated intraspecific variation within this species in these two traits expressed as one principal component. Correlation analysis revealed that intraspecific variation in salt tolerance was not strongly associated with intraspecific variation in plant morphological traits, leaf rolling, or leaf expansion rates.