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Pollination and Floral Ecology is the most comprehensive single-volume reference to all aspects of pollination biology--and the first fully up-to-date resource of its kind to appear in decades. This beautifully illustrated book describes how flowers use colors, shapes, and scents to advertise themselves; how they offer pollen and nectar as rewards; and how they share complex interactions with beetles, birds, bats, bees, and other creatures. The ecology of these interactions is covered in depth, including the timing and patterning of flowering, competition among flowering plants to attract certain visitors and deter others, and the many ways plants and animals can cheat each other.

Breeding systems play an essential role in plant sexual reproduction and influence speciation and extinction processes. However, our understanding of the breeding systems for particular neotropical angiosperm families is inadequate. The Pineapple family (Bromeliaceae) is one of the few indigenous and highly diverse plant lineages native to the American Continent and is a resource for the ornamental plant industry. Bromeliads have a remarkable history of adaptive radiation, yet the role of breeding systems in their evolution and ecology is still unknown. This review aims to establish the current state of knowledge on breeding systems in Bromeliaceae by identifying general patterns, data limitations, and information gaps. We compiled data on self-compatibility (SC), autonomous self-fertilization (selfing), and apomixis based on a thorough review of the scientific literature from 1990 to 2020. The final database included 177 entries, which represented 26 genera and 152 species (4.1% of the family). Two-thirds of the studies were conducted on species from highly diverse genera: Aechmea , Pitcairnia , Tillandsia , and Vriesea . Bromeliaceae exhibit a wide variety of breeding systems (SC and selfing). Subfamilies Pitcairnioideae (sensu stricto) and Tillandsioideae had higher values of SC and selfing, although some of the most investigated genera in each subfamily exhibited contradictory patterns and data for subfamilies considered ancestral were absent. Complete apomixis was rare, but it was more prevalent in Pitcairnioideae. The evolution of autofertility is likely the combined result of floral herkogamy as well as the species’ self-compatibility. Our present understanding of the evolutionary advantages of selfing in Bromeliaceae is limited and deserves further investigation.

The water shortage in China, particularly in Northwest China, is very serious. There is, therefore, great potential for improving the water use efficiency (WUE) in agriculture, particularly in areas where the need for water is greatest. A two-season (2012 and 2013) study evaluated the effects of irrigation and fertilizer rate on tomato (Lycopersicum esculentum Mill., cv. “Jinpeng 10”) growth, yield, and WUE. The fertilizer treatment significantly influenced plant height and stem diameter at 23 and 20 days after transplanting in 2012 and 2013, respectively. As individual factors, irrigation and fertilizer significantly affected the leaf expansion rate, but irrigation × fertilizer had no statistically significant effect on the leaf growth rate at 23 days after transplanting in 2012. Dry biomass accumulation was significantly influenced by fertilizer in both years, but there was no significant difference in irrigation treatment in 2012. Our study showed that an increased irrigation level increased the fruit yield of tomatoes and decreased the WUE. The fruit yield and WUE increased with the increased fertilizer rate. WUE was more sensitive to irrigation than to fertilization. An irrigation amount of 151 to 208 mm and a fertilizer amount of 454 to 461 kg·ha−1 (nitrogen fertilizer, 213.5–217 kg·ha−1; phosphate fertilizer, 106.7–108 kg·ha−1; and potassium fertilizer, 133.4–135.6 kg·ha−1) were recommended for the drip fertigation of tomatoes in greenhouse.

Pollen tube guidance precedes the double fertilization of flowering plants. Here, we report the identification of a small maize protein of 94 amino acids involved in short-range signaling required for pollen tube attraction by the female gametophyte. ZmEA1 is exclusively expressed in the egg apparatus, consisting of the egg cell and two synergids. Chimeric ZmEA1 fused to green fluorescent protein (ZmEA1:GFP) was first visible within the filiform apparatus and later was localized to nucellar cell walls below the micropylar opening of the ovule. Transgenic down-regulation of the ZmEA1 gene led to ovule sterility caused by loss of close-range pollen tube guidance to the micropyle.

The shift from outcrossing to selfing is common in flowering plants, but the genomic consequences and the speed at which they emerge remain poorly understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self compatible <200,000 years ago. We report a C. rubella reference genome sequence and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor Capsella grandiflora. We found a clear shift in the expression of genes associated with flowering phenotypes, similar to that seen in Arabidopsis, in which self fertilization evolved about 1 million years ago. Comparisons of the two Capsella species showed evidence of rapid genome-wide relaxation of purifying selection in C. rubella without a concomitant change in transposable element abundance. Overall we document that the transition to selfing may be typified by parallel shifts in gene expression, along with a measurable reduction of purifying selection.

We tested the effects of dehydrated sewage sludge fertilization on leaf mass production and ground cover of Terminalia argentea Mart. & Zucc. (Combretaceae) trees. In addition, we determined the abundance, diversity, and species richness of phytophagous Hemiptera, Sternorrhyncha predators (Hemiptera), and protocooperating ants visiting those plants. Numbers of leaves per branch, branches per tree, percentage of ground cover, abundance, species richness of phytophagous Hemiptera and Sternorrhyncha predators, including diversity of protocooperating ants, were greater on T. argentea trees fertilized with dehydrated sewage compared with unfertilized trees. We conclude that the addition of the dehydrated sludge aided the recovery of the severely disturbed area by increased fertilization of T. argentea trees used in the restorative process and increased the associated arthropod fauna.

In flowering plants, guidance of the pollen tube to the embryo sac (the haploid female gametophyte) is critical for successful fertilization. The target embryo sac may attract the pollen tube as the final step of guidance in the pistil. We show by laser cell ablation that two synergid cells adjacent to the egg cell attract the pollen tube. A single synergid cell was sufficient to generate an attraction signal, and two cells enhanced it. After fertilization, the embryo sac no longer attracts the pollen tube, despite the persistence of one synergid cell. This cessation of attraction might be involved in blocking polyspermy.

Upon gamete fusion, animal egg cells secrete proteases from cortical granules to establish a fertilization envelope as a block to polyspermy 1 – 4 . Fertilization in flowering plants is more complex and involves the delivery of two non-motile sperm cells by pollen tubes 5 , 6 . Simultaneous penetration of ovules by multiple pollen tubes (polytubey) is usually avoided, thus indirectly preventing polyspermy 7 , 8 . How plant egg cells regulate the rejection of extra tubes after successful fertilization is not known. Here we report that the aspartic endopeptidases ECS1 and ECS2 are secreted to the extracellular space from a cortical network located at the apical domain of the Arabidopsis egg cell. This reaction is triggered only after successful fertilization. ECS1 and ECS2 are exclusively expressed in the egg cell and transcripts are degraded immediately after gamete fusion. ECS1 and ESC2 specifically cleave the pollen tube attractor LURE1. As a consequence, polytubey is frequent in ecs1 ecs2 double mutants. Ectopic secretion of these endopeptidases from synergid cells led to a decrease in the levels of LURE1 and reduced the rate of pollen tube attraction. Together, these findings demonstrate that plant egg cells sense successful fertilization and elucidate a mechanism as to how a relatively fast post-fertilization block to polytubey is established by fertilization-induced degradation of attraction factors. Fertilized Arabidopsis egg cells secrete endopeptidases into the extracellular space that cleave the pollen tube attractor LURE1, preventing polytubey.

Background The transition to self-fertilization has occurred repeatedly across diverse plant groups, and the evolutionary consequences of selfing typically suggest that a shift toward outcrossing is unlikely. However, we propose that polyploidization could drive changes in reproductive strategies by influencing traits associated with pollination. We explored various traits linked to the mating system across different ploidy levels within the polyploid Erysimum incanum species complex, which is generally considered a predominantly selfing species. Results Our results revealed significant variation in self-fertilization success across different ploidies and we also found significant differences among populations within the same ploidy level. Inbreeding depression is absent in diploids, it was present in hexaploids, while tetraploids exhibited intermediate values. Additionally, polyploids showed traits more commonly associated with outcrossing rather than self-fertilization. Finally, the high values of heterozygosity found in polyploid populations were contrary to our expectations due to the selfing evolutionary history of this species. Conclusions These findings suggest that polyploidy may facilitate the emergence of alternative reproductive strategies, driving diversification in mating systems within this selfing species complex. This phenomenon, not previously observed in the wild, opens new perspectives on the evolution of plant mating systems.

As species expand their geographic ranges, colonizing populations face novel ecological conditions, such as new environments and limited mates, and suffer from evolutionary consequences of demographic change through bottlenecks and mutation load accumulation. Self-fertilization is often observed at species range edges and, in addition to countering the lack of mates, is hypothesized as an evolutionary advantage against load accumulation through increased homozygosity and purging. We study how selfing impacts the accumulation of genetic load during range expansion via purging and/or speed of colonization. Using simulations, we disentangle inbreeding effects due to demography versus due to selfing and find that selfers expand faster, but still accumulate load, regardless of mating system. The severity of variants contributing to this load, however, differs across mating system: higher selfing rates purge large-effect recessive variants leaving a burden of smaller-effect alleles. We compare these predictions to the mixed-mating plant Arabis alpina , using whole-genome sequences from refugial outcrossing populations versus expanded selfing populations. Empirical results indicate accumulation of expansion load along with evidence of purging in selfing populations, concordant with our simulations, suggesting that while purging is a benefit of selfing evolving during range expansions, it is not sufficient to prevent load accumulation due to range expansion.