Composition of Sexual Fluids in Cycas revoluta Ovules During Pollination and Fertilization

The composition of fluids that mediate fertilization in cycads is described for the first time. Using tandem mass spectrometry, proteomes of two stages of fluid production, megagametophyte fluid and archegonial chamber fluid production, are compared in Cycas revoluta. These were compared with the proteome of another sexual fluid produced by ovules, the pollination drop proteins. Cycad ovules produce complex liquids immediately prior fertilization. Compared with the pollination drops that mainly had few proteins in classes involved in defense and carbohydrate modification, megagametophyte fluid and archegonial chamber fluid had larger proteomes with many more protein classes, e.g. proteins involved in programmed cell death. Using high-performance liquid chromatography, megagametophyte fluid and archegonial chamber fluid were shown to have elevated concentrations of smaller molecular weight molecules including glucose, pectin and glutamic acid. Compared to megagametophyte fluid, archegonial chamber fluid had elevated pH as well as higher osmolality.

Key Plant, Key Pests: Sago Palm (Cycas revoluta)

This series of Key Plant, Key Pests publications are designed for Florida gardeners, horticulturalists, and landscape professionals to help identify common pests associated with common Florida flora. This new 4-page publication of the UF/IFAS Environmental Horticulture Department provides information and general management recommendations for aulacaspis scale, other scales, mealybugs, and manganese deficiency. https://edis.ifas.ufl.edu/ep608

Aulacaspis yasumatsui Delivers a Blow to International Cycad Horticulture

The literature covering the biology, invasion chronology, host plant responses, and control efforts of the armored scale Aulacaspis yasumatsui Takagi (Hempitera: Diaspididae) is reviewed. The small size of this cycad pest and complex surface morphology of the host cycad organs combine to make visual detection of every cryptic infestation difficult or impossible to achieve. The international movement of Cycas revoluta Thunb. nursery plants and the presence of C. revoluta nursery industries in so many countries have enabled this pest to wreak havoc on the international cycad horticulture trade over the last 25 years. The short pre-oviposition period and considerable female fecundity lead to rapid population expansion on the plants initially infested in newly invaded regions. A depletion of non-structural carbohydrates accompanies long-term infestations and precedes plant death. Enemy escape within the invasive range allows the scale population growth to remain unchecked until anthropogenic efforts establish non-native biological control.

Distribution of adenylyl cyclase/cAMP phosphodiesterase gene, CAPE, in streptophytes reproducing via motile sperm

We recently isolated a novel adenylyl cyclase/cAMP phosphodiesterase gene from the liverwort, Marchantia polymorpha. The protein encoded by this gene has a class III adenylyl cyclase (AC) in the C-terminal domain and class I phosphodiesterase (PDE) in the N-terminal domain; therefore, we named it CAPE (COMBINED AC with PDE). CAPE protein is likely involved in spermatogenesis and sperm motility due to its tissue-specific expression pattern in M. polymorpha and the distribution of CAPE genes in streptophytes. However, little is known about the distribution of CAPE in gymnosperms that use motile sperm for fertilization, such as cycads and ginkgo. The present study aimed to isolate CAPE genes from the cycad, Cycas revoluta, the ginkgo, Ginkgo biloba, and the hornwort, Anthoceros agerestis. Sequences with high homology to CAPE were obtained from these species. Our analyses revealed that all plant taxonomic groups reproducing via motile sperm possessed CAPE, whereas those that do not produce motile sperm did not possess CAPE, with one exception in gymnosperm Cupressales. The phylogenic distribution of CAPE almost corresponds to the evolutionary history of motile sperm production and further suggests that CAPE may be involved in sexual reproduction process using motile sperm in streptophytes.

rbcL AND ITS BARCODING AND PHYLOGENETICS OF CYCAS PSCHANNAE Srivast & Singh

Barcoding of Cycas pschannae Srivast. & Singh from Andaman & Nicobar Islands was done with the help of rbcL and ITS(Standard Universal Barcode Sequence- CBoL) and submitted to GenBank. Phylogenetic relationship of this species was analyzed and Cladistic study of nine Cycas species from India and adjacent country including Cycas revoluta thunb had been conducted with help of BLAST tool by using rbcL barcode sequence, which reveals that Cycas pschannae has close relation with Cycas circinalis as compared to other Indian species.

Warm stratification improves embryos development and seed germination of Cycas revoluta

The broad objective of this research is to study the effect of warm stratification on Cycas revoluta zygotic embryos length, seed germination and plant development. Four warm treatments were applied to seeds. Our results showed that seeds storage at room temperature or 30°C improved significantly zygotic embryos length. Moreover, time of germination was significantly reduced with the warm stratification. The highest percentage of germination was obtained with seeds warm treated at 30°C for 2 months while only 25% of seeds were able to germinate in the control. Regarding seedlings development, our results demonstrated that warm stratification did not affect plant development. No significant differences have been recorded in all the evaluated parameters except for root length. Taken together, these results underlined the beneficial effect of warm stratification on Cycas revoluta seed germination and plant development and proposed a new method to improve seed germination of Cycas revoluta.

Registro de daño de Aulacoscelis melanocera (Coleoptera: Orsodacnidae) sobre Cycas revoluta (Cycadaceae) en Campeche, México

El 7 de mayo de 2018, en el jardín de un sitio arqueológico en el norte de Campeche, México, se observó una planta de Cycas revoluta con aproximadamente el 40 % del follaje dañado por un enjambre de Aulacoscelis melanocera (Coleoptera: Orsodacnidae). El presente trabajo constituye el primer registro de esta especie ocasionando daño severo en C. revoluta y su primer registro para el estado de Campeche.