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Plants respond to seasonal cues, such as changes in temperature and daylength, to synchronize flowering with optimal conditions. Greenup et al. (pp. 1165–1172) compare and contrast the molecular pathways controlling seasonal flowering responses in the model plant Arabidopsis with those of important cereal crops, such as wheat, rice and barley.
Based on the structure–function plant growth model GreenLab, Mathieu et al. (pp. 1173–1186) propose a dynamical system of plant growth where interactions between organogenesis and functional mechanisms are controlled by a single variable characteristic of the source–sink balance of the plant. This model is a step towards a theoretical tool to explore botanical behaviours and to study the reasons for plant phenotypic plasticity.
Illustrated versions of medieval manuscripts known as the Tacuinum Sanitatis contain a wealth of images of crop plants growing in situ. Paris et al. (pp. 1187–1205) establish the identity of the cucurbits and nightshades, most of which closely resemble extant market types. The depictions include some of the earliest known images of cucumber, casaba melon and aubergine.
Anssour et al. (pp. 1207–1217) create five independent lines of synthetic allotetraploid Nicotiana×obtusiata by crossing N. attenuata and N. obtusifolia and synthesized autotetraploids of the two species. Examination of genetic, genomic and phenotypic changes in these synthetic polyploids compared to those in the naturally occurring allopolyploids N. quadrivalvis and N. clevelandii provides new insight into evolutionary dynamics driven by polyploidy. (Featured article in ContentSelect on p. v.)
The properties of Nepenthes pitcher traps change significantly with pitcher age. Bauer et al. (pp. 1219–1226) report the development of trapping efficiency and natural prey capture, nectar secretion, pitcher odour and properties of the digestive fluid during the first 2 weeks after pitcher opening. They show that prey capture is a highly dynamic process strongly influenced by pitcher age. (Featured article in ContentSelect on p. v.)
Reproductive success of plants is influenced by various factors. In the slipper orchid Cypripedium japonicum, Sun et al. (pp. 1227–1237) find that an increase in conspecific flower abundance negatively influences male reproductive success, but has no effect on female reproductive success. Phenotypic selection analysis indicates that earlier or asynchronous flowering is advantageous for both male and female reproductive success.
Stylosanthes spp. (stylo) is one of the most important tropical pasture legumes used widely on acid soils, where Al toxicity and P deficiency are two major limiting factors for plant growth. Du et al. (pp. 1239–1247) suggest that possible physiological mechanisms of stylo adaptation to low-P acid soils might involve superior ability of the roots to tolerate Al toxicity and to utilize organic P and Al-P.
Many kinds of attachment have evolved among climbing plants, such as twining stems, hooks and tendrils. However, some species can climb by simply attaching to host vegetation via anchor-like branches. Ménard et al . (pp. 1249–1259) reveal how a species of Manihot (Euphorbiaceae) of French Guiana with this relatively unspecialized climbing mode can grow either as treelets or branch-climbing phenotypes in open or closed conditions.
The literature reports a variable effect of priming on subsequent seed longevity in air-dry storage. For mature Digitalis purpurea seeds, Butler et al . (pp. 1261–1270) show that priming benefits the shortest-lived fraction of the seed population, but is detrimental to the longest-lived seeds. The longevity of aged seeds also increases in response to a single or multiple cycles of priming.
The existence of allelopathy is often controversial in ecology because of methodological issues. Viard-Crétat et al . (pp. 1271–1278) assess the inhibitive effect of an over-dominant species, Festuca paniculata, on neighbouring recruits. Using a pot experiment in natural conditions, they find that polyphenol release in leachates could be one of the mechanisms limiting the establishment of other species. (Featured article in ContentSelect on p. vi.)
Fitness depends on variation in multiple traits. Milla et al. (pp. 1279–1289) propose that multiple trait interactions in annuals may differ among populations of a given species, leading to differing fitness outcomes depending on the way traits interrelate to each other across ontogeny. Using structural equation modelling, they find that phenological, growth and reproductive traits exert different direct and indirect effects over fitness in three populations of Lupinus angustifolius from contrasting latitudinal origins.
Chantre et al. (pp. 1291–1301) show that Lithospermum arvense thermal-germination response is adequately described by assuming a normal distribution of both base and maximum germination temperatures in the seed population. The after-ripening process is characterized by a progressive increase in the mean maximum-germination temperature and a reduction in the thermal-time requirements for germination at sub-optimal temperatures.
Atriplex tatarica has two types of seeds with different dormancy levels. Kochánková and Mandák (pp. 1303–1313) detect significant correlations between basic population genetic parameters and population germination characteristics. Individual seed types are not influenced in the same way: whereas germination of the dormant type of seed is under strong genetic control, germination of the non-dormant seed type is not.
Using a pot experiment, Bancal (pp. 1315–1324) finds that the equation relating the amount of N in wheat at anthesis to its remobilization afterwards exhibits a negative intercept, challenging the concept of nitrogen remobilization efficiency. In plants with intact ears, grain N filling is determined by sources only (N remobilization and N uptake), without a direct effect of grain number and thus of sink size.
Normand et al . (pp. 1325–1336) show that the relative position of a mango growth unit, apical or lateral, affects its morphology (stem and leaf traits) and functioning (branching, flowering and fruiting). Morphological traits are involved in different ways in the determinism of flowering and fruiting. Flowering appears to be regulated by factors related to the growth-unit's relative position.
Some grasses exhibit summer dormancy, which confers superior drought survival. Volaire et al. (pp. 1337–1346) show that summer dormancy is triggered only under long days, invalidating the role of intense water deficit as inductive in a range of forage and native grasses. However, a late-spring drought tends to increase ABA accumulation and summer drought survival in tall fescue and cocksfoot.
A number of theories suggest that fluctuation in seedling establishment success facilitates plant species' coexistence. Working with two UK clover species, Hanley and Sykes (pp. 1347–1353) suggest that when coupled with spatio-temporal variation in seedling herbivory, covariance in seedling growth and defence against herbivore attack is critical to fluctuations in seedling establishment and thus plant coexistence. (Featured article in ContentSelect on p. vi.)