Effects of gamma radiations on morphological and physiological traits of finger millet (Eleusine coracana (L.) Gaertn.)

The present study was carried out to analyse the effect of gamma radiation on morpho-physiological parameters of seven days old M1 seedlings of Eleusine coracana (L.) Gaertn. (finger millet). The finger millet seeds were irradiated with different doses of viz., 100 Gy, 200 Gy, 300 Gy, 400 Gy, 500 Gy, 600 Gy, 700 Gy, 800 Gy, 900 Gy and 1000 Gy of gamma ray. Higher doses of gamma rays induced substantial reduction in mean performance of morphological and physiological traits. However, lower doses showed stimulatory effects on morphological and physiological traits. The results revealed a progressive decrease in chlorophyll fluorescence with increasing dose of gamma irradiation. Among all the mutagen doses used, 600 Gy gamma irradiated seeds showed enhanced mean performance of morphological and physiological traits in finger millet. Hence 600 Gy gamma rays may be employed in other crop species to improve the agro-economic traits

Physiological and Genetic Analysis of Leaves from the Resprouters of an Old Ginkgo biloba Tree

Ginkgo biloba is a well-known long-lived tree with important economical, ornamental and research value. New stems often resprout naturally from the trunk or roots of old trees to realize rejuvenation. However, the physiological and molecular mechanisms that underlie the resprouting from old trees are still unknown. In this study, we investigated a 544-year-old female ginkgo tree with vigorous resprouters along the trunk base in Yangzhou, China. We compared the morphological and physiological traits of leaves between resprouters (SL) and old branches (OL) and found a significantly higher thickness, fresh weight, and water content in SL. In particular, the depth and number of leaf lobes were dramatically increased in SL, suggesting the juvenile characteristics of sprouters in old ginkgo trees. Transcriptome data showed that the expression of genes related to photosynthetic capacity, the auxin signaling pathway, and stress-associated hormones was upregulated in SL. Importantly, levels of the most important secondary metabolites, including kaempferol, isorhamnetin, ginkgolide A, ginkgolide B, and ginkgolide C, were significantly higher in SL. We also identified high expression of key genes in SL, such as PAL and FLS, which are involved in flavonoid synthesis, and GGPS, which is involved in the synthesis of terpene lactones. These findings reveal the distinct physiological and molecular characteristics as well as secondary metabolite synthesis in leaves of resprouting stems in old ginkgo trees, providing new insight into rejuvenation physiology in old tree aging.

Morphological, physiological, pests and diseases responses of citrus seedling cultivars, and their contribution to cultivar classification under nursery house and open field

Information of morphological, physiological, and pests and diseases traits between Siam or Tangerine (C. nobilis L.) and Keprok or Mandarin (C. sinensis) seedlings group under nursery and open filed condition in Indonesia has limited. The contribution of morphological and physiological characters to cultivar classification of Siam and Mandarin group has also not been yet documented. The aims of this research were to evaluate the morphological, physiological, pests and diseases responses of citrus seedling cultivars, and their contribution to cultivar classification. This research was conducted at Tlekung Experimental Garden, Citrus and Subtropical Fruits Research Institute, Batu, East Java, Indonesia from February to December 2020. One-year-old budded seedlings were planted in plastic bags (size 15x30 cm) and put in both a nursery house and open field. The plastic bags were filled with mixed media (rice hull, soil, and compost) with the ratio of 1:1:1. The experimental design was a Two Stage Nested Design consisted of two factors, these were factor A: locations (nursery house and open field) and factor B as a nested-on factor A: cultivars (Siam cv. Pontianak, Siam cv. Banjar, Siam cv. Madu, Keprok cv. Kacang, Keprok cv. Terigas, Keprok cv. Madura and Keprok cv. Gayo). The results showed that the highest flush growth percentage was showed by Keprok cv. Madura grown under open field condition, while the biggest rootstock diameter was obtained from Siam cv. Madu grown in nursery house. Siam cv. Madu grown in open field also produced the highest root dry weight and stomata density. In terms of pests and diseases, aphids (Aphis gossypii) and leaf miner (Phyllocnistis citrella) have only been affected by locations, while for diseases was not found in this study. Contribution of morphological and physiological traits to citrus cultivars classification were about 64.70%. The average percentage of change in growth and develop capacity of Keprok group from open field to the nursery house increased by 2.35%, whereas for Siam one tended to decrease by 8.96%. In general, responses of morphological and/or physiological traits between Siam and mandarin group two locations were varied. Morphological and physiological traits may also useful for supporting genetically evaluation in improving citrus breeding programs.

Leaf traits of sal (Shorea robusta Gaertn.) populations selected from different regions of Bangladesh

This study investigated the variation in leaf traits of Sal (Shorea robusta Gaertn.) by collecting leaf samples from the natural populations of Sal distributed in Madhupur National Park, Cumilla and Dinajpur areas of Bangladesh. Soil samples were collected at 0 - 10 cm depth near the base of the tree trunk of the respective plants selected for the collection of leaf samples. Soils were analyzed for moisture content, pH, electrical conductivity, available N, total P, and organic C contents. Data showed a range of variation in the responses of leaf traits of the three populations. However, none of the morphological and physiological traits showed significant differences except chlorophyll content (p = 0.0047). Conversely, significant difference appeared in most of the leaf anatomical properties such as stomatal pore index (p = 0.0369), open-close behavior (p = < 0.0001) and stomatal density (p = 0.0008) among the three forests. Stomatal density, pore index, and percent open stomata were higher in the Madhupur forest, while closed stomata were significantly higher in the Dinajpur forest. Thus, the present study indicated that although all leaf traits did not show a similar trend of response, leaf stomata were more responsive to different geographical distribution, which could be attributed to the variation in soil moisture conditions. Dhaka Univ. J. Biol. Sci. 30(2): 317-324, 2021 (July)

Contrasting Manual and Automated Assessment of Thermal Stress Responses and Larval Body Size in Black Soldier Flies and Houseflies

Within ecophysiological and genetic studies on insects, morphological and physiological traits are commonly assessed and phenotypes are typically obtained from manual measurements on numerous individuals. Manual observations are, however, time consuming, can introduce observer bias and are prone to human error. Here, we contrast results obtained from manual assessment of larval size and thermal tolerance traits in black soldier flies (Hermetia illucens) and houseflies (Musca domestica) that have been acclimated under three different temperature regimes with those obtained automatically using an image analysis software (Noldus EthoVision XT). We found that (i) larval size estimates of both species, obtained by manual weighing or by using the software, were highly correlated, (ii) measures of heat and cold tolerance using manual and automated approaches provided qualitatively similar results, and (iii) by using the software we obtained quantifiable information on stress responses and acclimation effects of potentially higher ecological relevance than the endpoint traits that are typically assessed when manual assessments are used. Based on these findings, we argue that automated assessment of insect stress responses and largescale phenotyping of morphological traits such as size will provide new opportunities within many disciplines where accurate and largescale phenotyping of insects is required.

Screening of Pearl Millet [Pennisetum glaucum (L.) R. Br.] Germplam Lines for Drought Tolerance Based on Morpho-physiological Traits and SSR Markers

Aim: The present study was undertaken to analyze genetic diversity among pearl millet genotypes based on drought linked morpho-physiological and microsatellite markers. Study Design: In the present investigation, 96 pearl millet germplasm lines were screened against drought using different morphological and physiological traits along with SSR markers. Place and Duration of the Study: The present study was conducted at College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya, Gwalior, M.P., India during July 2019 to December, 2020. Methodology: The study was conducted to record different morphological and physiological traits related to drought tolerance and susceptibility. Thirty five microsatellite markers were also used in laboratory to analyze the variability among pearl millet genotypes under study. Results: Pearl millet genotypes were grouped according to their morpho-physiological characteristics. Among 35 SSR markers, twenty-two were successfully amplified across all germplasm lines and seven SSR markers were found to be polymorphic and fifteen markers were monomorphic. All seven polymorphic SSR markers were used consequently for amplification of all the 96 germplasm lines. The range of PIC value was 0.0939 to 0.2980 with the average of 0.2274. The highest PIC value was recorded for the markers Xibmsp26 and Xibmsp29 (0.2980), followed by Xibmsp03 (0.2392), Xibmsp29 (0.2392), Xibmsp06 (0.2289) and Xibmsp07 (0.1948) while the lowest for the marker Xibmsp01 (0.0939). The range of major allele frequency value was 0.7604 to 0.9479 with the average of 0.8363. The range of genetic diversity value was 0.0987 to 0.3644 with the average of 0.2665. Conclusions: According to the morpho-physiological data a total of 22 pearl millet genotypes were found to be grouped distantly from rest of the genotypes. These genotypes had shown their drought tolerance bahaviour however, rests of the genotypes were found to be susceptible against drought.