The implication of leaf anatomical structure for the selective breeding of lilacs

The cultivars of the common lilac (Syringa vulgaris) grown in the south of the Russian Far East are not always winter-hardy and are often damaged by fungal diseases due to a very humid climate. A promising trend in the selective breeding of lilacs in Russia is the creation of new breeding material based on the gene pool of the broadleaf lilac (S. oblata) and its hybrids in order to introduce valuable adaptive traits into cultivars. The present work aimed to identify the traits of leaf anatomy in species and cultivars of Syringa resistant and susceptible to Pseudocercospora lilacis, the causative agent of brown leaf spot disease. The study was carried out on the living collection of the Botanical Garden-Institute, Far Eastern Branch, Russian Academy of Sciences (Vladivostok). The leaf anatomical structure of two Syringa species showing different degrees of resistance to P. lilacis in the monsoon climate of the Far East (resistant S. oblata and weakly resistant S. vulgaris, and also their hybrid cultivars) has been analyzed. The differences between species, subspecies, and cultivars are quantitative: they differ in the number of spongy mesophyll layers, the cell height in the first layer of palisade mesophyll, the cell height in the upper and lower epidermises, and the thickness of both mesophylls. The interspecific hybrids resistant or weakly resistant to P. lilacis (brown leaf spot disease) mainly retain the leaf anatomy structure of the maternal plant. One of the traits determining the resistance of hybrid lilac cultivars is an increased number of spongy mesophyll layers in the leaf blade. The study of leaf anatomy has shown that the four-layered spongy mesophyll leaf parenchyma correlates with the resistance of lilacs from the subsection Euvulgaris to P. lilacis. In S. oblata, this trait is inherited down the maternal line. To establish lilac cultivars resistant to fungal diseases, it is advisable to cross the two species (S. oblata and S. vulgaris) or their cultivars using one of S. oblata subspecies as a maternal plant.

Drought resistance mechanisms of Phedimus aizoon L.

Phedimus aizoon L. is a drought-resistant Chinese herbal medicine and vegetable. However, its drought tolerant limit and the mechanism of drought tolerance are unknown, which restricts the promotion of water-saving cultivation of Phedimus aizoon L. in arid areas. To solve the above problem, we carried out a 30-day-long drought stress experiment in pots that presented different soil water contents and were divided into four groups: control check, 75–80% of the maximum water-holding capacity (MWHC); mild drought, 55–60%; moderate drought, 40–45%; and severe drought, 20–25%. The dynamic changes in both plant physiological indexes from 10 to 30 days and leaf anatomical structure on the 30th day of stress were recorded. The results show that Phedimus aizoon L. grew normally under mild drought stress for 30 days, but the growth of the plants became inhibited after 20 days of severe drought and after 30 days of moderate drought. At the same time, Phedimus aizoon L. physiologically responded to cope with drought stress: the growth of the root system accelerated, the waxy layer of the leaves thickened, and the dark reactions of the plants transformed from those of the C3 cycle to CAM. The activity of antioxidant enzymes (SOD, POD and CAT) continuously increased to alleviate the damage caused by drought stress. To ensure the relative stability of the osmotic potential, the contents of osmoregulatory substances such as proline, soluble sugars, soluble protein and trehalose increased correspondingly. Although Phedimus aizoon L. has strong drought stress resistance, our experimental results show that the soil available water content should not be less than 27% during cultivation.

Karakter Anatomi Daun sebagai Bentuk Adaptasi Tumbuhan Penyusun Zonasi Mangrove di Banggai Kepulauan, Provinsi Sulawesi Tengah

Mangrove is an essential ecosystem that are located in the transition area of fresh and sea water. Therefore, species that grow are typical species that are able to adapt to the saline environment. The aim of this research is to characterize leaf anatomical structure for every species that compose the communities found in each mangrove zonations, including their similarities and dissimilarities characteristic. Sampling of examined leaf was carried out in the mangrove areas of Peling Island and Bakalan Island by making plots in four sites of the mangrove ecosystem area. Methods for leaf anatomical preparations were carried out using the paraffin-tert-butanol and paradermal sections. Anatomical characters as an adaptation to saline habitat are found in all species of mangrove plants, including thick cuticle and epidermal cells, thick leaves and water-storage tissue (hypodermis). In addition, there is found the presence of cork warts and sclereid as characteristic of the genus Rhizophora. Based on quantitative character observations, the mesophyll (palisade to sponge) ratio range from 0.28 ± 0.04 μm to 1.19 ± 0.42 μm, leaf thickness ratio 289,41 ± 38,21 μm to 695,20 ± 97,50 μm and the highest stomata density is owned by Lumnitzera littorea

Anatomical Structure and Terpenoid Content of Zodia (Evodia suaveolens Scheff) Leaves

Zodia (Evodia suaveolens Scheff) is a member of Rutaceae contain terpenoids, triterpenoids, alkaloids, flavonoids, and xanthones which have anti-mosquito activity. This research aimed to observe the anatomical structure, the location, and distribution of terpenoid based on the leaves' age. Anatomical slides preparation of leaves were made using the paraffin embedding method with safranin staining. The distribution of terpenoid was analyzed by the histochemical assay. Leaf anatomical structure shows that the 3rd and 6th leaf bifacial (dorsiventral) consisted of the upper epidermis, mesophyll (palisade and sponge), collateral vascular bundle, parenchyma midrib, abaxial epidermis and oil glands in mesophyll that is underneath both epidermises. The diameter of oil glands with larger sizes was on the 6th leaf, whereas the density is not different in the 3rd and 6th leaves. The histochemical test showed that terpenoid was observed in the leaf vascular bundles, oil glands, and epidermis.

Limitations in photosynthesis of sugar beets under water deficit and rehydration conditions

Background: Limiting factors in photosynthesis includes stomatal limitations, mesophyll limitations, and biochemical limitations, and mesophyll limitations are the leading limiting factors in photosynthesis as shown by many studies. Mesophyll conductance (gm) exerts significant influences on the photosynthetic capacity of crops, playing a decisive role in mesophyll limitations. The limiting factors in photosynthesis for many crops under water deficit and rehydration conditions have been studied, but few studies of this kind on sugar beet can be found. Results: Our study aimed to analyze the dynamic changes of mesophyll limitations, stomatal limitations, and biochemical limitations by examining the influences of water deficit and rehydration on photosynthetic characteristics, electron transport, and leaf anatomical structure. According to the analysis on photosynthetic characteristics, severe deficit irrigation treatment significantly decreased photosynthesis rate, light saturation point, and CO2 saturation point. After rehydration, there was no difference in photosynthetic characteristics between the well irrigated sugar beets and the ones with severe deficit irrigation treatment. The analysis on leaf anatomical structure found that sugar beets dealt with water deficit by increasing leaf (mesophyll) thickness, and the severe deficit irrigation treatment significantly decreased the number of chloroplasts without influencing each one in terms of shape and cross-section area. No significant influence of water deficit was found on the electron transport rate (Jflu) of sugar beets during the process of CO2 assimilation. Conclusions: Therefore, deficit irrigation treatments cannot significantly influence photosynthetic assimilation of sugar beets. The analysis of limitations in photosynthesis showed that the stomatal and biochemical limitations increased while the mesophyll limitations decreased when sugar beets were under water deficit; however, the stomatal and biochemical limitations decreased while the mesophyll limitations increased after rehydration. The photosynthesis of sugar beets was mainly influenced by mesophyll limitations, and the limiting factors changed significantly only for severe deficit irrigation treatment.

A new species of Trembleya (Melastomataceae: Microlicieae) with notes on leaf anatomy and generic circumscription

A new species of Trembleya that was first recognized by Auguste François Marie Glaziou is described. Line drawings, photographs, descriptions of the leaf anatomical structure, SEM images, distribution maps, conservation status, and comments on the generic circumscription of Trembleya are provided. The new species appears to be endemic to the Chapada dos Veadeiros in Goiás, Brazil. It is characterized by its oblong-lanceolate leaf blades (1.4–4.5 × 0.3–0.9 cm) that are papyraceous, 3–5-nerved from the base and glandular-punctate on both surfaces, tertiary veins not evident, well-developed inflorescences, flowers with subisomorphic stamens that are completely yellow and ovaries with 3(–4) locules. A conservation assessment of Endangered (EN) is recommended for this species based on IUCN Red List Categories and Criteria.