The legacy of the extinct Neotropical megafauna on plants and biomes

Large mammal herbivores are important drivers of plant evolution and vegetation patterns, but the extent to which plant trait and ecosystem geography currently reflect the historical distribution of extinct megafauna is unknown. We address this question for South and Central America (Neotropical biogeographic realm) by compiling data on plant defence traits, climate, soil, and fire, as well as on the historical distribution of extinct megafauna and extant mammal herbivores. We show that historical mammal herbivory, especially by extinct megafauna, and soil fertility explain substantial variability in wood density, leaf size, spines and latex. We also identified three distinct regions (‘‘antiherbiomes’’), differing in plant defences, environmental conditions, and megafauna history. These patterns largely matched those observed in African ecosystems, where abundant megafauna still roams, and suggest that some ecoregions experienced savanna-to-forest shifts following megafauna extinctions. Here, we show that extinct megafauna left a significant imprint on current ecosystem biogeography.

The CRISPR/Cas9-Mediated Modulation of SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE 8 in Alfalfa Leads to Distinct Phenotypic Outcomes

Alfalfa (Medicago sativa L.) is the most widely grown perennial leguminous forage and is an essential component of the livestock industry. Previously, the RNAi-mediated down-regulation of alfalfa SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE 8 (MsSPL8) was found to lead to increased branching, regrowth and biomass, as well as enhanced drought tolerance. In this study, we aimed to further characterize the function of MsSPL8 in alfalfa using CRISPR/Cas9-induced mutations in this gene. We successfully generated alfalfa genotypes with small insertions/deletions (indels) at the target site in up to three of four MsSPL8 alleles in the first generation. The efficiency of editing appeared to be tightly linked to the particular gRNA used. The resulting genotypes displayed consistent morphological alterations, even with the presence of up to two wild-type MsSPL8 alleles, including reduced leaf size and early flowering. Other phenotypic effects appeared to be dependent upon mutational dosage, with those plants with the highest number of mutated MsSPL8 alleles also exhibiting significant decreases in internode length, plant height, shoot and root biomass, and root length. Furthermore, MsSPL8 mutants displayed improvements in their ability to withstand water-deficit compared to empty vector control genotypes. Taken together, our findings suggest that allelic mutational dosage can elicit phenotypic gradients in alfalfa, and discrepancies may exist in terms of MsSPL8 function between alfalfa genotypes, growth conditions, or specific alleles. In addition, our results provide the foundation for further research exploring drought tolerance mechanisms in a forage crop.

Of mutualism and migration: will interactions with novel ericoid mycorrhizal communities help or hinder northward Rhododendron range shifts?

Rapid climate change imperils many small-ranged endemic species as the climate envelopes of their native ranges shift poleward. In addition to abiotic changes, biotic interactions are expected to play a critical role in plant species’ responses. Below-ground interactions are of particular interest given increasing evidence of microbial effects on plant performance and the prevalence of mycorrhizal mutualisms. We used greenhouse mesocosm experiments to investigate how natural northward migration/assisted colonization of Rhododendron catawbiense, a small-ranged endemic eastern U.S. shrub, might be influenced by novel below-ground biotic interactions from soils north of its native range, particularly with ericoid mycorrhizal fungi (ERM). We compared germination, leaf size, survival, and ERM colonization rates of endemic R. catawbiense and widespread R. maximum when sown on different soil inoculum treatments: a sterilized control; a non-ERM biotic control; ERM communities from northern R. maximum populations; and ERM communities collected from the native range of R. catawbiense. Germination rates for both species when inoculated with congeners' novel soils were significantly higher than when inoculated with conspecific soils, or non-mycorrhizal controls. Mortality rates were unaffected by treatment, suggesting that the unexpected reciprocal effect of each species’ increased establishment in association with heterospecific ERM could have lasting demographic effects. Our results suggest that seedling establishment of R. catawbiense in northern regions outside its native range could be facilitated by the presence of extant congeners like R. maximum and their associated soil microbiota. These findings have direct relevance to the potential for successful poleward migration or future assisted colonization efforts.

Evaluating the Growth-promoting Effects of Microbial Biostimulants on Greenhouse Floriculture Crops

Microbial biostimulants can promote ornamental plant growth during production and improve crop performance under abiotic stresses. Even though biostimulants have shown potential in many agricultural applications, the effectiveness and specificity of many products are not well understood. The objective of this study was to analyze the growth-promoting effects of microbial biostimulants during the greenhouse production of floriculture crops. We evaluated 13 biostimulant products in greenhouse-grown zinnia (Zinnia elegans ‘Magellan Ivory’) and petunia (Petunia ×hybrida ‘Carpet White’) at low fertility (one-third of the optimal fertilizer concentration). Biostimulant products 1 and 2 containing multiple species of beneficial bacteria and fungi, and product 10 containing Bacillus subtilis QST 713, were found to increase various aspects of plant growth, including the growth index, leaf chlorophyll content (SPAD index), and shoot biomass. Both flower biomass and numbers were greater in petunia treated with product 1, and leaf size increased in zinnia treated with products 1, 2, and 10. Plants treated with these effective biostimulants at low fertility had similar or better growth and quality than untreated plants grown under optimal fertility. The concentration of various nutrient elements in leaves was higher in zinnia plants treated with biostimulant products 1, 2, or 10 compared with the negative control. Some putative mechanisms for biostimulant effectiveness, the possible reasons for biostimulant ineffectiveness, and the potential for using biostimulants as a sustainable cultural strategy are discussed. This study provides useful information about microbial biostimulant effectiveness, which is important for the development and utilization of biostimulants in the greenhouse production of floriculture plants.

Different Sweet Orange–Rootstock Combinations Infected by Candidatus Liberibacter asiaticus under Greenhouse Conditions: Effects on the Scion

The devastating citrus disease huanglongbing (HLB) associated with the phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas) has caused a more than 70% reduction in citrus production since its discovery in Florida in 2005. Most citrus scion cultivars are sensitive to HLB, whereas some cultivars used as rootstocks are tolerant. Using such tolerant rootstocks can help trees to cope better with the disease’s impact. Evaluating rootstock effects on a grafted scion in the field takes many years, but shorter-term evaluation is imperative to aid in rootstock selection for an HLB-endemic production environment. In this study, we investigated grafted healthy and CLas-infected citrus trees under controlled greenhouse conditions. The objectives were to identify traits suitable for assessing grafted tree tolerance in advance of longer-term field studies and aiding in the selection of superior rootstock cultivars. We assessed 10 commercially important rootstocks grafted with ‘Valencia’ sweet orange scion and with known field performance. At 6, 9, 15, and 21 months after graft inoculation (mai), leaf CLas titers were determined and canopy health was evaluated. Plants were destructively sampled at 21 mai to assess plant biomasses and other physiological and horticultural variables. There was little influence of the rootstock cultivar on CLas titers. Surprisingly, few HLB foliar disease symptoms and no differences in soluble and nonsoluble carbohydrate concentrations were measured in infected compared with healthy plants, despite high CLas titers and significant reductions in plant biomasses. Most trees on rootstocks with trifoliate orange parentage were less damaged by HLB than other rootstocks, although results did not always agree with reported field performance. Among the different variables measured, leaf size appeared to be most predictive for grafted tree assessment of HLB sensitivity. The results of this study provide a better understanding of the strengths and weaknesses of assessing rootstock influence on grafted tree performance in a controlled greenhouse environment. Although such studies provide valuable information for cultivar tolerance to HLB, other rootstock traits will ultimately contribute to field survival and productivity in an HLB endemic production environment.

Phytoclimatic spectrum of Weeds flora of Toormang Valley, Dir Lower, Koh-E-Hindukush Range, Pakistan

Four season’s data of floristic structure and biological spectrum of Toormang Valley, Dir lower was explored during 2018-2019. The flora comprised 238 species, 164 genera associated with 60 families. The most prevailing family was Asteraceae with 42 species (17.64%), trailed by Rosaceae 16 (6.72%), Brassicaceae 13(5.46%), Solanaceae 11 (4.62%), Papilionaceae 10 (4.20%), Apiaceae, and Poaceae each with 9(3.78%), Lamiaceae 8 (3.36%), Boraginaceae, Euphorbiaceae and Moraceae each contributed by 7 species (2.94%), Amaranthaceae and Cucurbitaceae each consisted of 6 species (2.52%), Caryophyllaceae and Chenopodiaceae each with 5(2.10%) while rest of 23 families contributed by 01 species each (0.42%). The largest genera were Euphorbia (6 species), followed by Sonchus and Medicago (4 species) each. Therophytes were the dominant with 102 species (42.85%), followed by nanophanerophytes with 27 (11.34%), hemicryptophytes with 25 (10.50%), chamaephytes with 20(8.40%), microphanerophytes with 18(7.56%), megaphanerophytes with 16(6.72%), geophytes with 15 (6.30%), mesophanerophytes with 14 (5.88%) and parasite with 1 species (0.42%). The observations on leaf size revealed that microphyll was the prevailing class with 73 species (30.67%), followed by mesophyll 69(28.99%), nanophyll 60 (25.21%), leptophyll 23(9.66%), macrophyll 8(3.36%), megaphylly 4(1.1.68%) and aphyllous with 1 species (0.42%). Simple lamina species 154 while 5 species have spiny lamina shape.

FLORISTIC COMPOSITION AND BIOLOGICAL SPECTRUM OF BARA GALI, ABBOTTABAD

Floristic composition and Phytosociological studies on the flora of Bara Gali District Abbottabad, Pakistan was conducted. The altitudinal range of the Bara Gali is from 2100-2370 meter. From the study area 50 species belong to 33 families were recorded. Herbaceous flora was dominant with 35 species, shrubs with 10 species and tree with 5 species. Asteraceae was dominant having 6 species. Microphyll dominant leaf size spectra and hemicryptophytes were dominant life form in the study area. This study provide information about the floristic composition of Bara Gali.

Exploring Children's Science and Mathematics Ability with Leaf Diary: A Case Study

Purpose – This study aims to explore Leaf diary activity to develop the Science and Mathematics ability of children aged 6 years.Design/methods/approach – The method used is a case study. The unit of analysis is based on predetermined criteria, using the purposive sampling technique. Research informants are mentors and children involved in leaf diary activity in Solok, Indonesia. The data collection process used participant observation, documentation, and in-depth interviews. Data analysis used structural analysis techniques.Findings – The results showed that leaf diary activity could develop: (1) children's ability to classify leaves based on their shape; (2) the ability to compare leaf size based on length, as well as large or small size.Research implications/limitations – All research informants were from Solok District, Indonesia, which may limit the generalizability of the findings.Practical implications – This case study contributes to the implementation of Leaf diary as an alternative activity that teachers or parents can do to develop children's science and mathematics ability.Originality/value – Leaf diary activity can help children explore the natural environment so that basic science and math abilities and concepts in this activity are carried out well. Paper type Case study

Classification and Characterization of the Manoor Valley’s (Lesser Himalaya) Vegetation from the Subtropical-Temperate Ecotonal Forests to the Alpine Pastures along Ecological Variables

Plant species are distributed in different types of habitats, forming different communities driven by different sets of environmental variables. Here, we assessed potential plant communities along an altitudinal gradient and their associations with different environmental drivers in the unexplored Manoor Valley (Lesser Himalaya), Pakistan. We have implemented various ecological techniques and evaluated phytosociological attributes in three randomly selected 50 m-transects within each stand (a total of 133) during different seasons for four years (2015–2018). This phytosociological exploration reported 354 plant species representing 93 different families. The results revealed that the Therophytic life form class dominated the flora, whereas Nanophyll dominated the leaf size spectra. There were a total of twelve plant communities identified, ranging from the lowest elevations to the alpine meadows and cold deserts. The maximum number of species were found in Cedrus–Pinus–Parrotiopsis community (197 species), in the middle altitudinal ranges (2292–3168 m). Our results showed that at high altitudes, species richness was reduced, whereas an increase in soil nutrients was linked to progression in vegetation indicators. We also found different clusters of species with similar habitats. Our study clearly shows how altitudinal variables can cluster different plant communities according to different microclimates. Studies such as ours are paramount to better understanding how environmental factors influence ecological and evolutionary aspects.

​Advances in Breeding of Jackfruit Crop: A Review

The improvement of jackfruit is required to make it amenable for intensive cultivation and make it suitable for a variety of value-added products. There is a significant variation for various traits such as plant phenology, leaf shape, leaf size, fruit shape, fruit size, number of fruits per plant, flake colour, number of flakes per fruit etc. The jackfruit crop has long juvenility, high clonal heterozygosity, recalcitrant type of seeds make it difficult to improvement of jackfruit varieties or hybrids, but on the other hand ease of vegetative propagation of hybrids or varieties is advantageous for the jackfruit breeder. The development of jackfruit is again based on the selection of clones especially for small-sized quality fruits, dwarf, less gum type, disease and pest resistance etc. The detailed knowledge on phenology, inheritance pattern and advanced techniques for hybrid/variety development will be useful to overcome the problems of jackfruit breeding viz fruit size, gummier fruits, susceptibility to disease and pests etc. The development of genetic markers has further reduced the uncertainty in the breeding of jackfruit and maintains the hybrid/varietal populations with desirable characteristics.