The effect of temperature on yield soybeans ( Glycine max (L.) Merr.), is often underestimated despite reports a significant relationship between and growing season temperatures. identification genotypes having heat tolerance appears to be warranted, but simple, rapid technique for measuring high needed. A previously used assessing genotypic differences in membrane thermostability (heat tolerance) sorghum Sorghum bicolor Moench) was evaluated use soybeans. involves the measurement by...

The first three branches of the angiosperm phylogenetic tree consist eight families with ∼201 species plants (the ANITA grade). oldest flower fossil for group is dated to Early Cretaceous (115-125 Mya) and identified Nymphaeales. flowers extant in grade are small, pollen edible reward (rarely nectar or starch bodies). Unlike many gymnosperms that secrete "pollination drops," ANITA-grade members examined thus far have a dry-type stigma. Copious secretions stigmatic fluid restricted...

The origin and rapid diversification of flowering plants has puzzled evolutionary biologists, dating back to Charles Darwin. Since that time a number key life history morphological traits have been proposed as developmental correlates the extraordinary diversity ecological success angiosperms. Here, I identify several innovations were fundamental lability angiosperm reproduction, hence their diversification. In gymnosperms pollen reception must be near egg largely because sperm swim or are...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCOPROGEN, A NEW GROWTH FACTOR FOR COPROPHILIC FUNGIC. W. Hesseltine, C. Pidacks, A. R. Whitehill, N. Bohonos, B. L. Hutchings, and J. H. WilliamsCite this: Am. Chem. Soc. 1952, 74, 5, 1362Publication Date (Print):March 1, 1952Publication History Published online1 May 2002Published inissue 1 March 1952https://pubs.acs.org/doi/10.1021/ja01125a525https://doi.org/10.1021/ja01125a525research-articleACS PublicationsRequest reuse permissionsArticle...

This paper examines two assumptions that have formed the basis for much of past and present work on hybrid zones. These derive from observation crosses between genetically divergent individuals (e.g., different subspecies, species, etc.) often give rise to genotypes are less fertile or viable than those produced similar individuals. The first assumption is natural hybridization will not affect evolutionary history hybridizing forms because there a low probability producing novel with higher...

The white oaks Quercus gambelii and Q. grisea overlap in distribution New Mexico Arizona. Within the region of overlap, there are numerous instances contact between two taxa. In some areas morphologically, intermediate trees common, whereas others, morphologically rare or absent. We describe a set RAPD markers that distinguish species use these to examine patterns gene exchange an area San Mateo Mountains Mexico. highly coincident with morphology confirm hybridization takes place. Despite...

The recent consensus that Amborellaceae, Nymphaeales, and Austrobaileyales form the three earliest-diverging lineages of angiosperms has led comparative biologists to reconsider origin early developmental evolution angiosperm seven-celled/eight-nucleate (Polygonum-type) female gametophyte. Illicium mexicanum (Illiciaceae; Austrobaileyales) develops a four-celled/four-nucleate ontogenetic sequence gametophyte is consistent with all other also Nymphaeales likely plesiomorphy angiosperms. A...

Early angiosperm history was marked by a shift from long to an exceptionally brief fertilization process. Ovules and their associated female gametophytes became greatly reduced in size, resulting the precocious production of eggs abbreviated pollination-to-fertilization period. The small ovules accompanied origin enclosing carpel (angiospermy) accessory organs that together formed ephemeral reproductive shoot, or flower. An unappreciated innovation, which arose within context these...

Male gametophytes of seed plants are sexually immature at the time they dispersed as pollen, but approximately 30% flowering have tricellular pollen containing fully formed sperm anthesis. The classic study Brewbaker (1967: American Journal Botany 54: 1069-1083) provided a powerful confirmation long-standing hypothesis that had many parallel and irreversible origins within angiosperms. We readdressed main questions with modern comparative phylogenetic methods.We used our own more recent...

SUMMARY1. A factor necessary for the growth of Pilobolus kleinii, P. longipes, umbonatus, and roridus has been demonstrated.2. This named Coprogen.3. stock medium consisting dung decoction oatmeal extract described carrying species Pilobolus.4. block inoculum assay developed Coprogen in agar Petri dishes.5. The pH maximum shown to be above 7.6. Growth kleinii liquid media made possible resulting a that is both quantitative qualitative.7. Certain aspects spore germination have studied genus Pilobolus.

Abstract Premise Co‐occurring plant species that share generalist pollinators often exchange pollen. This heterospecific pollen transfer (HPT) impacts male and female reproductive success through loss reductions in seed set, respectively. The resulting fitness cost of HPT imposes selection on traits (e.g., floral color shape), yet we currently lack strong predictors for the post‐pollination fate pollen, especially within community phylogenetic contexts. Methods We investigated at three...

A remarkable number of the defining features flowering plants are expressed during life history stage between pollination and fertilization. Hand pollinations Amborella trichopoda (Amborellaceae) in New Caledonia show that when stigma is first receptive, female gametophyte near maturity. Pollen germinates within 2 h, pollen tubes with callose walls plugs grow entirely secretions from to stylar canal ovarian cavity. enter micropyle 14 double fertilization occurs 24 h. Hundreds base stigma,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoprogen, the Isolation of a New Growth Factor Required by Pilobolus SpeciesC. Pidacks, A. R. Whitehill, L. M. Pruess, C. W. Hesseltine, B. Hutchings, N. Bohonos, and J. H. WilliamsCite this: Am. Chem. Soc. 1953, 75, 23, 6064–6065Publication Date (Print):December 1, 1953Publication History Published online1 May 2002Published inissue 1 December 1953https://pubs.acs.org/doi/10.1021/ja01119a529https://doi.org/10.1021/ja01119a529research-articleACS...

Among flowering plants, females often have little control over the genetic relatedness of pollen deposited on stigmas. Thus, postpollination processes are primary importance for mate discrimination. The ability to screen and select among male gametes during tube growth within female tissues stigma, style, ovary is critical process choice reproductive isolation. However, direct evidence mechanistic/developmental associated with in plants sparse. We studied contribution postpollination,...

Abstract The monosporic seven-celled/eight-nucleate Polygonumtype female gametophyte has long served as a focal point for discussion of the origin and subsequent evolution angiosperm gametophyte. In gametophytes, two haploid nuclei are incorporated into central cell, fusion sperm cell with binucleate produces triploid endosperm complement maternal one paternal genomes, characteristic most angiosperms. We document development four-celled/four-nucleate in Nuphar polysepala (Engelm.) infer its...

For more than a century, most biologists have viewed the structural diversity of angiosperm female gametophytes as trivial variants reproductive process. However, analysis variation among from an evolutionary developmental perspective can provide new insights into patterns innovation and evolution flowering plants. The key is to link innovations (perhaps even adaptations) associated with endosperm genetics ploidy. Selection has been hypothesized favor endosperms higher ploidy,...

Genetic variability for heat tolerance has been alluded to in several crop species but few reports of inheritance or heritabilities the trait are reported. Some screening tolerance, employing controlled environmental chambers, reported only limited numbers plants can be evaluated such facilities. A technique measuring membrane thermostability (heat tolerance) was used screen segregating soybean ( Glycine max (L.) Merr.) populations derived from crosses tolerant and intolerant parents grown...

Abstract Background A number of innovations underlie the origin rapid reproductive cycles in angiosperms. critical early step involved modification an ancestrally short and slow-growing pollen tube for faster longer distance transport sperm to egg. Associated with this shift are predominantly callose (1,3-β-glucan) walls septae (callose plugs) angiosperm tubes. Callose synthesis is mediated by synthase (CalS). Of 12 CalS gene family members Arabidopsis , only one ( CalS5 ) has been directly...

An important aspect of the evolution carpel closure, or angiospermy, is relationship between pollen tube growth patterns and internalization pollen-tube pathway. True involving postgenital fusion inner margins, inferred to have arisen once within ancient order Nymphaeales, in common ancestor Nymphaeaceae. We studied development, from pollination fertilization, a natural population Nymphaea odorata, using hand pollinations timed flower collections. Pollen germinates stigmatic secretions 15...