Leaf Lamina Area Research Articles

Influence of air dust on anatomo-morphological and biochemical parameters of Plantago Major L

Pollution has a great impact on the environment. Plants being the representatives of autotrophic organisms are the first to face it. The photosynthesis suppression, water exchange violation, transpiration reduction, growth general oppression and plants’ development are exposed to pollutants. This causes changes in leaf coloration, necroses, premature leaf fall, changes in growth form. The effect of air dust on anatomo-morphological parameters of plantain and the effect of dust pollution on plantain’s (Plantago major L.) production processes have been studied, the dust-holding capacity of plantain leaves has been estimated. The correlation between the dust pollution level and the stomata density in the leaves’ epidermis of model species has been found out. Mass of aboveground organs (g) and leaf lamina area (cm2), the number of stomata on the leaf surface (pcs./mm2), the dust accumulation level on the leaf surface (g) have been analyzed in model species. Weighing was carried out with an accuracy of 0.001 g on electronic scales. According to the performed analysis, we have come to the conclusions: species of the plantain have 10 to 50 mg of dust particles deposited on the leaf surface, the size of leaf plates and the mass of plantain's terrestrial organs decrease as the level of air pollution increases. It should be underlined that air pollution causes an increase in the density of stomata in plantain associated with a reduction in the area of the assimilating apparatus and it can be viewed as one of the compensatory mechanisms.

The scaling relationships between leaf sheath size and leaf lamina size in six bamboo species

ABSTRACT The scaling relationship between functional traits of leaf sheath and leaf lamina in bamboo is of significant importance in regulating bamboo growth, yet related studies are lacking. In this study, we collected a total of 2006 leaves from six bamboo species (including Pleioblastus argenteostriatus, Pleioblastus chino var. hisauchii, Pleioblastus fortunei, Pleioblastus kongosanensis f. aureostriatus, Pleioblastus maculatus, and Pleioblastus viridistriatus) growing in Nanjing, China, and measured leaf sheath length (SL), leaf sheath fresh mass (SFM), leaf lamina length (LL), leaf lamina area (LA), and leaf lamina fresh mass (LFM). We used reduced major axis regression protocols to fit the scaling relationships between various measures of leaf lamina and leaf sheath. For each individual species and the pooled data of six species, allometric relationships were found in lamina (LFM vs. LA) and sheath (SFM vs. SL), respectively. We also found robust allometric relationships between leaf sheath and leaf lamina (LA vs. SL and LFM vs. SL). These results revealed the strong coupling among leaf traits in terms of morphology and mass, providing insights into the understanding of the physiological process of bamboo growth.

"Diminishing returns" and leaf area-biomass scaling of ferns in subtropical ecosystems.

Foliage leaves are the primary photosynthetic organ of the majority of vascular plants, and their area vs. biomass scaling relationships provide valuable insights into the capacity and investment in light interception, which is critical to plant growth and performance. The "diminishing returns" hypothesis (DRH), which is based primarily on data from gymnosperms and angiosperms, posits that leaf (lamina) area scales with leaf dry mass. on average with a scaling exponent less than 1.0. However, it remains uncertain whether DRH applies to ferns or whether ecological factors affect the scaling exponents governing fern leaf morphometrics. To address this issue, 182 individuals of 28 subtropical ferns species were studied at low, medium, and high elevations (i.e., 600m, 900m, and 1200m, respectively) in Mount Wuyi National Park, Jiangxi Province, China. The scaling relationships between leaf area and leaf biomass for individual and total leaf of ferns at different elevations were examined by using standardized major axis regression protocols. Analyses of the 28 fern species (using Blomberg K-value protocols) indicated no phylogenetic biases among the species compositions of the three different elevations. In addition, at the individual plant level, individual leaf area (ILA) did not differ significantly among the three different elevations (P > 0.05). However, individual leaf mass (ILM) was significantly higher at 900m than at 1200m (P < 0.05), resulting in a significantly higher leaf mass per area (LMA) at the 900m elevation than at the 600m and 1200m elevations (P < 0.05). The ILA and ILM at the 900m elevation were significantly higher than at the 600m elevation (P < 0.05). At the species level, ILA and ILM did not differ significantly among the three elevations (P > 0.05). The total leaf area per individual (TLA) did not differ significantly across the different elevations (P > 0.05). However, total leaf mass per individual (TLM) did differ significantly (P < 0.05). At the individual plant level, the scaling exponents for ILA vs. ILM and TLA vs. TLM at the three different elevations were all significantly less than 1.0 (P < 0.05), which was consistent with the DRH. At the species level, the scaling exponents for the ILA vs. ILM were significantly less than 1.0 at the middle and high elevations, but not at the low elevation. The scaling exponents of the TLA and TLM were numerically highest in the middle elevation, and all were less than 1.0 for the three elevations. These results indicate that the scaling relationships of leaf area versus mass of subtropical ferns at different elevations support the DRH hypothesis. The study further informs our understanding of the resource allocation strategies of an ancient and diverse plant lineage.

Mechanisms of Plant Resistance to Rice Leaf Mite, Oligonychus oryzae Hirst (Acari: Tetranychidae)

Due to the changing climatic scenario rice leaf mite, Oligonychus oryzae Hirst becoming one of the major pests of paddy and cause severe yield loss. In this context, field experiment was carried out at Tamil Nadu Agricultural University, Coimbatore to screen popular rice varieties for their resistance against O. oryzae. The results revealed that negative correlation existed between the mite population and the leaf morphological characters viz., the number and length of trichomes, thickness of the leaf lamina and leaf area. ADT 53 a resistant variety recorded 28.48 mg/g of total carbohydrates, while TN 1 susceptible variety recorded 79.59 mg/g. As compared to susceptible variety, the resistant varieties have higher phenol content. The resistant variety Ptb 33 (8.107 changes in OD value min/g of fresh leaf tissue) recorded increased peroxidase activity. Both healthy and infested leaves (0.567 and 0.611 changes in OD value/ min/ g of leaf tissue) from the resistant cultivar Ptb 33 had higher levels of Polyphenol oxidase as compared to other varieties.

Influence of Leaf Age on the Scaling Relationships of Lamina Mass vs. Area.

Leaf lamina mass and area are closely correlated with the photosynthetic capacity and competitive ability of plants, whereas leaf age has been demonstrated to affect physiological processes such as photosynthesis. However, it remains unknown whether the lamina mass vs. area scaling relationship is influenced by leaf age, which is important for understanding plant adaptive strategies and, more broadly, resource utilization and growth. We measured the leaf functional traits of five leaf-age groups of Photinia × fraseri for a total of 1,736 leaves. ANOVA followed by Tukey’s honestly significant difference test was used to compare the functional traits among the five leaf-age groups. Reduced major axis regression protocols were used to fit the scaling relationship between lamina mass and area, and the bootstrap percentile method was used to compare the lamina mass vs. area scaling relationships among the leaf-age groups. Lamina area, and the ratio of lamina dry mass to lamina fresh mass increased with increasing leaf age. Lamina fresh mass per unit area, and lamina dry mass per unit area both exhibited a parabolic-like trend as leaf age increased, i.e., at the leaf maturation stage, it showed a slight but significant decline. The phenomenon called diminishing returns were confirmed by each of the five leaf-age groups, i.e., all of the numerical values of the scaling exponents of lamina mass vs. area were significantly greater than 1. There were significant differences in the scaling exponents of lamina mass vs. area for the leaves across different sampling times. The scaling exponents were lower at the early rapid growth stage, indicating a lower cost for increasing leaf area compared to the leaf maturation stage. These data are consistent with leaves undergoing a transition from resource acquisition to resource conservation in the process of their development and growth.

Weightage of Mature Leaf in Eucalyptus Clones in Characterization and Variability Assessment for DUS Testing (Distinct, Uniform and Stable) using MuInvariant Analysis

The studies were undertaken to develop DUS testing guidelines of selected 25 Eucalyptus clones from commonly available 82 clones from Institute of Forest Genetics and Tree Breeding (IFGTB). The results revealed that all individual clones showed considerable variation in qualitative, pseudo-qualitative and quantitative characteristic traits (17 morpho-metric traits) of Mature leaves and were grouped into different categories. The traits like leaf shape, base shape, apex shape, margin, symmetry, petiole length, lamina area, length, breadth, perimeter, convex perimeter, curve length, curve width, roundness, aspect ratio, convex area and full ratio were identified as grouping traits. The weightage of the quantitative traits were proven by Multi-variant analysis. In Canonical Discriminant analysis, three significant discriminant functions, which had Eigen value &gt;1 and this 3 values accounted for a cumulative variation of 76.2%. In Principal Component Analysis, two significant principal components (PCs) extracted had Eigen value &gt;1 and out of 12 this two values accounted for a cumulative variation of 89.47%. In Eucalyptus clones the dendrogram drawn depicted three distinct clusters based on the similarity using Pearson correlation coefficient method. The dendrogram drawn depicted three distinct clusters based on the euclidean distances grouped them by dissimilarity using agglomerative hierarchical clustering technique (Ward’s method).

Evaluation of the State of the Environment in Yoshkar-Ola Using Morphometric Indicators of Betula pendula Roth

The results of long-term bioindication studies aimed to evaluate the state of the silver birch (Betula pendula Roth) in Yoshkar-Ola under different anthropogenic load conditions are presented. An increase in the morphometric indices of the shoot system and leaf lamina area under anthropogenic load was observed. The fluctuating asymmetry (FA) index of B. pendula leaves growing on short shoots did not depend on the ontogenetic state of the tree, while in the case of leaves collected from long shoots, such a dependence was revealed. The most informative morphometric parameters of B. pendula indicating the state of the environment included the FA index of leaves growing on short shoots and the damaged leaf area.

Scaling of petiole anatomies, mechanics and vasculatures with leaf size in the widespread Neotropical pioneer tree species Cecropia obtusa Trécul (Urticaceae).

Although the leaf economic spectrum has deepened our understanding of leaf trait variability, little is known about how leaf traits scale with leaf area. This uncertainty has resulted in the assumption that leaf traits should vary by keeping the same pace of variation with increases in leaf area across the leaf size range. We evaluated the scaling of morphological, tissue-surface and vascular traits with overall leaf area, and the functional significance of such scaling. We examined 1,271 leaves for morphological traits, and 124 leaves for anatomical and hydraulic traits, from 38 trees of Cecropia obtusa Trécul (Urticaceae) in French Guiana. Cecropia is a Neotropical genus of pioneer trees that can exhibit large laminas (0.4m2 for C. obtusa), with leaf size ranging by two orders of magnitude. We measured (i) tissue fractions within petioles and their second moment of area, (ii) theoretical xylem hydraulic efficiency of petioles and (iii) the extent of leaf vessel widening within the hydraulic path. We found that different scaling of morphological trait variability allows for optimisation of lamina display among larger leaves, especially the positive allometric relationship between lamina area and petiole cross-sectional area. Increasing the fraction of pith is a key factor that increases the geometrical effect of supportive tissues on mechanical rigidity and thereby increases carbon-use efficiency. We found that increasing xylem hydraulic efficiency with vessel size results in lower leaf lamina area: xylem ratios, which also results in potential carbon savings for large leaves. We found that the vessel widening is consistent with hydraulic optimisation models. Leaf size variability modifies scaling of leaf traits in this large-leaved species.

New methods in genotype diagnostics of small-fruit crops for intensive gardening

Physiological and morphological studies of red Russian and foreign breeding red currant varieties were carried out for establishing intensive plantings and introduction. Varieties Dana, Niva, Vika, Hollandische Rote are yielding, highly resistant and promising for introduction and industrial cultivation, during dry periods they are able to regulate metabolism through changing indicators of water balance (water deficit, fractional composition of water) and photosynthetic apparatus of leaves (leaf lamina area). Using Natali, Shchedraya and Jonkheer Van Tets varieties in production is possible with application of artificial irrigation. Selyanochka variety is most affected by weather conditions and is recommended to be grown in temperate climate area. Physiological and morphological methods of research allow to diagnose the genotypes resistance of garden crops to growing period abiotic factors at the early stages of plant development, they are confirmed by field observations and are promising in diagnosis for establishing intensive gardens and berry-fields.

Contrasting leaf-trait strategies in dominant liana and tree species of Indian tropical dry evergreen forest

Recent studies have revealed convergence in the variation of leaf traits across various plant life-forms on a global scale. This study aims to analyze and compare the leaf-trait strategies of dominant liana and tree species in Indian tropical dry evergreen forest (TDEF). The study also checks whether these life-forms differ in their resource acquisition strategies explained by the variance in their leaf functional traits. The present study was carried out in a permanent plot established in a TDEF site on the Coromandel Coast of India. We selected ten dominant species of lianas and trees to analyze and compare their leaf-trait strategies. For each species, we collected 30 healthy sun leaves from at least eight individuals. The collected leaf samples were analyzed for various leaf functional traits using standard protocol. Lianas had higher specific leaf area and mass-based leaf nitrogen than the trees. Trees had higher leaf lamina area, leaf thickness, leaf mass per area, leaf tissue density and C:N than the lianas. Lianas and trees in the studied site differed significantly in six out of seven leaf-functional traits analyzed. The observed leaf trait strategies of lianas in TDEF could offer competitive advantage for them over trees.

Natural selection and neutral evolutionary processes contribute to genetic divergence in leaf traits across a precipitation gradient in the tropical oak Quercus oleoides.

The impacts of drought are expanding worldwide as a consequence of climate change. However, there is still little knowledge of how species respond to long-term selection in seasonally dry ecosystems. In this study, we used QST -FST comparisons to investigate (i) the role of natural selection on population genetic differentiation for a set of functional traits related to drought resistance in the seasonally dry tropical oak Quercus oleoides and (ii) the influence of water availability at the site of population origin and in experimental treatments on patterns of trait divergence. We conducted a thorough phenotypic characterization of 1912 seedlings from ten populations growing in field and greenhouse common gardens under replicated watering treatments. We also genotyped 218 individuals from the same set of populations using eleven nuclear microsatellites. QST distributions for leaf lamina area, specific leaf area, leaf thickness and stomatal pore index were higher than FST distribution. Results were consistent across growth environments. Genetic differentiation among populations for these functional traits was associated with the index of moisture at the origin of the populations. Together, our results suggest that drought is an important selective agent for Q.oleoides and that differences in length and severity of the dry season have driven the evolution of genetic differences in functional traits.

Wheat lines exhibiting variation in tolerance of Septoria tritici blotch differentiated by grain source limitation

Septoria tritici blotch (STB) is the most damaging disease of wheat crops in Europe. Because of the partial nature of genotypic resistance or the increasing resistance against fungicides, the tolerance, i.e. maintaining yield in the presence of expressed disease, is a relevant alternative. Tolerance is generally estimated through the yield loss per unit of source reduction, contrasts of tolerance between genotypes have been observed previously suggesting that either increasing the source availability or improving the use of stored assimilate could improve tolerance. This paper aims at developing a source/sink approach to understand the tolerance mechanism and identifying potential traits to increase tolerance of STB. A field experiment was designed to explore the relation between tolerance of STB and source/sink balance. Based on six wheat genotypes contrasting for tolerance exposed to natural STB epidemics, late nitrogen fertilization and a 50% spikelet removal were applied to change the source/sink balance. The tolerance of genotypes was quantitatively estimated over three additional field experiments. We found that STB tolerance was correlated with traits of healthy crops (high individual grain weight and high proportion of green leaf lamina area as leaf 3; flag leaf=leaf 1). The spikelet removal revealed a highly variable degree of source limitation for grain filling amongst the six genotypes. Thus, we proposed an easily calculated index that highly correlated positively with the labor intensive estimation of STB tolerance. Finally, potential yield and tolerance were not correlated, which suggests that breeding for yield performance and tolerance could be possible.

Preliminary application of tapered glass capillary microbeam in MeV-PIXE mapping of longan leaf for elemental concentration distribution analysis

This study was aimed at understanding elemental concentration distribution in local longan leaf for how the plant was affected by the environment or agricultural operation. The analysis applied the MeV-microbeam particle induced X-ray emission (PIXE) mapping technique using a home-developed tapered glass capillary microbeam system at Chiang Mai University. The microbeam was 2-MeV proton beam in 130 µm in diameter. The studying interest was in the difference in the elemental concentrations distributed between the leaf midrib and lamina areas. The micro proton beam analyzed the leaf sample across the leaf midrib edge to the leaf lamina area for total 9 data requisition spots. The resulting data were colored to form a 1D-map of the elemental concentration distribution. Seven dominant elements, Al, S, Cl, K, Ca, Sc and Fe, were identified, the first six of which were found having higher concentrations in the midrib area than in the lamina area, while the Fe concentration was in an opposite trend to that of the others.

Morphological and physiological characteristics of rice leaves in response to PASP-urea and optimized nitrogen management

ABSTRACTPolyaspartic acid (PASP)-urea is known to increase crop yield. Field experiments were conducted to compare the morphological and physiological characteristics of the leaves between plots treated with urea (conventional urea or PASP-urea) and subject to different nitrogen (N) management methods [farmers’ standard fertilization practice (FFP, two splits) or optimized N management (ONM, four splits)] in Sichuan, China, in 2014 and 2015. A no-added-N plot served as the control. Grain yield was significantly associated with increased number of green leaves, total leaf area, chlorophyll concentration of rice leaves after the heading stage, photosynthetic rate per leaf lamina and accumulated temperature of senescence rate acceleration and deceleration. PASP-urea significantly enhanced the photosynthetic capacity of leaves to improve dry matter accumulation rate of the panicle after the heading stage over conventional urea, mainly by increasing the number of green lamina, leaf lamina area, chlorophyll concentration and photosynthetic rate per leaf lamina, as well as delaying senescence of the flag leaf. Compared with FFP, the ONM substantially improved the photosynthetic capacity of leaves to enhance dry matter accumulation rate of the panicle. Therefore, the ONM is a rational approach to applying PASP-urea that can improve grain yield by improving photosynthetic capacity.

Light-exposed shoots of seven coexisting deciduous species show common photosynthetic responses to tree height.

Functional traits of light-exposed leaves have been reported to show tree height-dependent change. However, it remains unknown how plastic response of leaf traits to tree height is linked with shoot-level carbon gain. To answer this question, we examined the photosynthetic properties of fully lit current-year shoots in crown tops with various heights for seven deciduous broad-leaved species dominated in a cool-temperate forest in northern Japan. We measured leaf mass, stomatal conductance, nitrogen content, light-saturated net photosynthetic rate (all per leaf lamina area), foliar stable carbon isotope ratio, and shoot mass allocation to leaf laminae. We employed hierarchical Bayesian models to simultaneously quantify inter-trait relationships for all species. We found that leaf and shoot traits were co-varied in association with height, and that there was no quantitative inter-specific difference in leaf- and shoot-level plastic responses to height. Nitrogen content increased and stomatal conductance decreased with height. Reflecting these antagonistic responses to height, photosynthetic rate was almost unchanged with height. Photosynthetic rate divided by stomatal conductance as a proxy of photosynthetic water use efficiency sufficiently explained the variation of foliar carbon isotope ratio. The increase in mass allocation to leaves in a shoot compensated for the height-dependent decline in photosynthetic rate per leaf lamina mass. Consequently, photosynthetic gain at the scale of current-year shoot mass was kept unchanged with tree height. We suggest that the convergent responses of shoot functional traits across species reflect common requirements for trees coexisting in a forest.

Synergistic effect of phytohormones on pigment and fine structure of chloroplasts in flag leaf of wheat plants irrigated by seawater

Plant hormones play vital roles in the ability of plants to acclimatize to varying environments by mediating growth, development and nutrient allocation. The present investigation was undertaken to have some information about interactive effects of seawater salinity and some plant growth regulators (gibberellic acid, indole acetic acid or abscisic acid) on leaf area, pigment and chloroplast ultrastructure as well as saccharides and protein content of wheat flag leaf. In the majority of cases, seawater at 10 or 25% increased pigment content, particularly carotenoids. On the other hand seawater reduced leaf lamina area, Hill activity and sucrose as well as polysaccharides and protein. The interactive effect of seawater and growth regulators accelerated the production of Chl a, Chl b and carotenoids by increasing the values of these pigment. Furthermore, grain pretreatment with gibberellic acid, indole acetic acid or abscisic acid induced marked increase in leaf lamina area, Hill activity and sucrose as well as polysaccharides and protein. Irrigation of wheat plants by seawater at 10 or 25% caused dramatic changes in chloroplast ultrastructure of flag leaf. These changes include disorganized membrane system, disruption of bounding membrane, reduction in the size and number of starch grains and an increase in plastoglobuli. The presoaking of wheat grains in GA3, IAA or ABA resulted in an increase of plant tolerance against the adverse effect of seawater particularly at 10%. This resistance was estimated by the presence of normal chloroplast.

Identifying traits leading to tolerance of wheat to Septoria tritici blotch

Identifying tolerance traits to diseases in wheat genotypes has an increased interest to minimize pesticide use and to complement resistance and escape.Yield tolerance to Septoria tritici blotch (STB) was studied pooling up three experiments involving 18 genotypes, 5 years and 6 sites in France, amounting to 161 genotype×year×site×management combinations. Each combination involves a crop pair (treated or not against foliar diseases) repeated two to three times. Most crops were grown under high fertilization, and STB was the main disease present in untreated crops. Crop traits (ear density, grain number and weight, area of leaf laminas) were recorded; green area of leaf laminas over time was fitted to a Gompertz equation, producing metrics for senescence traits (time and duration).Over the whole dataset, LAI from 1.1 to 7.5m2m−2; yields from 280 to 1122gDMm−2 and relative yield losses up to 70% were recorded. Fungicide treated crops exhibited slightly larger ear density and leaf lamina area independently of the intensity of epidemics. As an overall trend, yield became more determined by source traits when epidemics occurred. Yield loss was proportional (r2=0.7) to senescence advance by disease. Decrease in grain number and weight were also correlated (r2=0.4 and 0.8, respectively) to yield loss. Two epidemic indices were built to compare data across year×site combinations. Then yield in untreated crop was predicted (r2=0.87) from yield in corresponding treated crop, and interaction of epidemic indices with traits of the treated crops that therefore were pointed out as responsible for tolerance variability. Late senescing crops exhibited a greater tolerance to epidemics. Conversely, grain weight was a major key of intolerance. To minimize the trade-off between yield potential and tolerance it is thus suggested to maximize grain number.This study represents a first step in identifying key traits involved in tolerance to STB in varying agronomic conditions and cultivars.

Soil water deficit decreases xylem conductance efficiency relative to leaf area and mass in the apple

It is generally postulated that at the tree scale a drought-related decrease in hydraulic conductance is balanced by a decrease of leaf area. We hypothesized that, at the individual leaf scale, drought affects the allometry between leaf area or mass and hydraulics, leading to a non-linear relationships between these traits. The study was conducted on well-watered and on water-stressed shoots of several apple genotypes covering an extended range of leaf area. Working on dried leaves, we measured leaf lamina area and mass and analyzed their relationships with the maximal xylem hydraulic conductance of the water pathway through the parent shoot and the petiole connected to the leaf lamina. Drought decreased leaf area and mass in absolute values. It also changes the allometric relationships between these two variables: for a same decrease of leaf dry mass the water-stressed shoot had a lower decrease of leaf dry area than the well-watered shoot. Our study also showed that drought affected the stem-to-petiole hydraulics with a higher hydraulic efficiency in the well-watered shoot compared to the water-stressed shoot. We discuss that, compared to the well-watered condition, drought not only decreased leaf size, but also reduced xylem efficiency through the stem-to-petiole pathway with regard to the leaf area and mass supplied.

The effect of interspecific hybridisation with Trifolium uniflorum on key white clover characteristics

A study was conducted to determine the effects of hybridisation with a wild relative, Trifolium uniflorum, on key morphological characteristics and N fixation of white clover (Trifolium repens). Overall, over 19 months under the conditions of the field environment used, dry matter (DM) production of the backcross 1 (BC1) generation was reduced compared with white clover, and did not increase with a second generation of backcrossing. The general morphological type of BC1 hybrids had a smaller leaf lamina area, shorter internodes and a more prostrate growth habit compared with white clover, which is likely to contribute to reduced DM production. Generally, lateral spread did not differ among BC1, backcross 2 (BC2) and white clover, except in spring when white clover had a wider spread than the hybrids. Hybridisation did not affect the proportion of shoot N derived from fixation, or shoot %N content. Fungal disease and virus symptoms were lower in the T. uniflorum parent than in white clover. This did not affect virus symptoms in the hybrids, and fungal disease scores were higher in BC1 than in the white clover parent. However, some hybrid families were more superior than others at maintaining (or improving) characteristics of their specific white clover parental cultivars, such as DM production, stolon density, growth habit, and resistance to shoot fungal diseases and viruses. This suggests it should be possible to develop elite hybrid breeding populations by recurrent selection of superior hybrid genotypes.

Drought resistance of Trifolium repens×Trifolium uniflorum interspecific hybrids

White clover (Trifolium repens L.) is a widely used and highly valued temperate legume; however, its productivity and survival are restricted under dryland and drought conditions. This study investigated whether drought resistance of white clover could be improved by interspecific hybridisation with Trifolium uniflorum L. After almost 4 months without irrigation in a rain-shelter facility, shoot dry weight (DW) decreased significantly less in first-generation backcross (BC1) hybrids (–47%) than second-generation backcross (BC2) hybrids (–68%) and white clover (–69%). Stolon morphological parameters such as internode length and leaf lamina area also decreased less under water stress in the BC1 hybrids than in BC2 and white clover. There was also lower senescence in BC1 under water stress than in the other clover types. Genotypes with smaller changes in leaf lamina area, internode length, senescence and lateral spread had smaller changes in shoot DW, and there were significant correlations between constitutive levels of some characteristics and the effect of water stress on shoot DW. Under water stress, the growth form of the BC1 hybrids was compact, dense and prostrate, whereas white clover was more spreading and open. Increased allocation of dry matter to roots under drought, and greater root diameter, may also have influenced the ability of BC1 hybrids to maintain water uptake and key physiological processes. Overall, the data confirm that the drought resistance of white clover can be improved through hybridisation with T. uniflorum.