Edge Effects in Small Forest Fragments: Why More Is Better?

Edge to interior gradients in forest fragments can influence the species composition and community structure as a result of variations in microenvironment and edaphic variables. We investigated the response of microenvironment and edaphic variables to distance from a tropical montane forest (locally known as shola)-grassland edge using one-edge and multiple-edge models. The edpahic variables did not show any differences between the grassland and shola soils. We observed that conventional one-edge models sufficiently explained variation trends in microenvironment along the edge to interior gradient in large fragments. As with other studies on small fragments though, we observed no edge effects with the use of a conventional one-edge model. However, the inclusion of multiple edges in small fragments signifycantly improved model fit. We can conclude that small fragments dominated by edge habitat may in fact resemble larger fragments with the inclusion of multiple edges. Our models did not evaluate non-linear effects which often better explain patterns in edge-interior gradients. The incorporation of such non-linear models in the system might further improve model fit.

Field Performance of Quercus bicolor Established as Repeatedly Air-Root-Pruned Container and Bareroot Planting Stock

Benefits of repeated air-root-pruning of seedlings when stepping up to progressively larger containers include excellent lateral root distribution immediately below the root collar and an exceptionally fibrous root ball. To evaluate long-term field performance of repeatedly air-root-pruned container stock, three plantings of swamp white oak (Quercus bicolor Willd.) 10 to 13 years old were located that also included bareroot planting stock. Initial and final stem diameter and height and above-ground green weights were determined on randomly selected trees at each site. On a site with a sandy, excessively drained, high pH soil, trees (age 10) from container stock were 1.5 times taller, 2.3 times larger in dbh, and 2.8 times greater in green weight than trees from bareroot stock which averaged only 2.9 m tall, 3.9 cm dbh, and 16.3 kg green weight. On a site with high clay, poor internal drainage, and frequent flooding, trees (age 12) from container stock were 1.4 times taller, 1.8 times larger in dbh, and 4.1 times greater in green weight than trees from bareroot stock which averaged 4 m tall, 7.3 cm dbh, and 28 kg green weight. On an upland site with deep loess soils, there was a trend for trees (age 13) from container stock to be only slightly larger than trees from bareroot stock with each stock type averaging 9.6 m tall, 20 cm dbh, and 177 kg green weight. Repeated air-root pruning produced lateral roots immediately below the root collar that resulted in large container stock with large well-balanced root systems that were competitive on harsh or less than ideal oak sites. Although the process is relatively labor intensive, propagation of repeatedly air-root-pruned container stock is readily adaptable internationally to locally available sources of organic matter and open-bottom containers.

The Shola (Tropical Montane Forest)-Grassland Ecosystem Mosaic of Peninsular India: A Review

Tropical montane forests (alternatively called tropical montane cloud forests or simply cloud forests) represent some of the most threatened ecosystems globally. Tropical montane forests (TMF) are characterized and defined by the presence of persistent cloud cover. A significant amount of moisture may be captured through the condensation of cloud-borne moisture on vegetation distinguishing TMF from other forest types. This review examines the structural, functional and distributional aspects of the tropical montane forests of peninsular India, locally known as shola, and the associated grasslands. Our review reveals that small fragments may be dominated by edge effect and lack an “interior” or “core”, making them susceptible to complete collapse. In addition to their critical role in hydrology and biogeochemistry, the shola-grassland ecosystem harbor many faunal species of conservation concern. Along with intense anthropogenic pressure, climate change is also expected to alter the dynamic equilibrium between the forest and grassland, raising concerns about the long-term sustainability of these ecosystems.

A Global Analysis of Temperature Effects on Populus Plantation Production Potential

The genus Populus contains some of the most economically important tree species and hybrids in the world. We compared productivity of short and long-rotation poplar plantations using published data from 23 countries to determine if climate, particularly temperature, had any effect on the observed patterns of productivity. We discovered that climate factors (related to temperature) and clone origin (pure species or hybrids) slightly influenced productivity of long rotation forests more than short rotation plantations. While long rotation plantation productivity exhibited positive correlations with increasing temperature during winter and decreasing heat during summer, short rotation plantations showed weak positive relationship among productivity and increasing yearly temperature and the number of hot days. It was apparent that short rotation plantations productivity was less dependent on regional climatic variables or origin of clone. However, it appears that overall, regardless of the system, Populus species are generally adapted to a range of climatic conditions where they are planted.

Genome-scale mRNA and miRNA transcriptomic insights into the regulatory mechanism of cucumber corolla opening

‘Corollas and spines’ is an important trait for fresh market cucumber. In a unique cucumber line, ‘6457’, the super ovary is much larger and corolla opening is delayed by 4–5 days, thus the resulting fruit has a flower that remains on the tip,which has a high commodity value. In this study, to better understand the molecular basis of corolla opening, mRNA and miRNA transcriptome analyses were performed during corolla development of the super and normal ovaries. A total of 234 differentially expressed miRNAs(DEMs) and 291 differentially expressed target genes(DE-target genes) were identified from four developmental stages, and the greatest number of DEMs was found at the yellow bud stage. Thirty of the DE-target genes were regulated by more than five DEMs, among which, CsHD-Zip was regulated by 28 DEMs,followed by DD2X(18). In addition, the expression patterns of miRNA_104, miRNA_157, miRNA_349, miRNA_242, and miRNA_98 were similar during corolla development, and they shared the same target gene, CsCuRX. Moreover, several critical candidate DEMs and DE-target genes were characterized and profiled by a qRT-PCR experiment. Three of the miRNAs, miRNA_157-CsCuRX, miRNA_411-CsGH3.6, and miRNA_161/297/257-CsHD-Zip, might be responsible for corolla opening in the cucumber super ovary. This integrated study on the transcriptional and post-transcriptional profiles can provide insights into the molecular regulatory mechanism underlying corolla opening in the cucumber.

The Ecological Classification of Coastal Wet Longleaf Pine (Pinus palustris) of Florida from Reference Conditions

Tropical storms, fire, and urbanization have produced a heavily fragmented forested landscape along Florida’s Gulf coast. The longleaf pine forest, one of the most threatened ecosystems in the US, makes up a major part of this fragmented landscape. These three disturbance regimes have produced a mosaic of differently-aged pine patches of single or two cohort structures along this coastline. The major focus of our study was to determine reference ecosystem conditions by assessing the soil biochemical properties, overstory stand structure, and understory plant species richness along a patch-derived 110-year chronosequence in order to accurately evaluate on-going longleaf pine restoration projects. This ecological dataset was also used to classify each reference patch as mesic flatwoods, wet flatwoods, or wet savanna. All of the reference locations were found to have similar soil types with no significant differences in their soil biogeochemistry. Mean diameter-at-breast height (DBH), tree height, and patch basal area increased as mean patch age increased. Stand growth reached a plateau around 80-90 years. Shrub cover was significantly higher in the matureaged patches (86-110 years) than in the young (6-10 years) or mid-aged (17-52 years) patches, despite prescribed fire. Plant species diversity as indicated by the Shannon-Wiener index decreased with patch age. Soil biogeochemical properties, forest structure, and understory species composition were effective for ecologically classifying our pine patches as 55 % mesic flatwoods, 20% wet flatwoods, and 25% wet savanna. Florida’s Gulf coastal wet longleaf pine flatwoods attain a structural and plant species equilibrium between 80-90 years.

Panicle-Cloud:An Open and Al-Powered Cloud Computing Platform for Quantifying Rice Panicles from Drone-Collected Imagery to Enable the Classification of Yield Production in Rice

Rice(Oryza sativa)is an essential stable food for many rice consumption nations in the world and,thus,the importance to improve its yield production under global climate changes.To evaluate different rice varieties'yield performance,key yield-related traits such as panicle number per unit area(PNpM^(2))are key indicators,which have attracted much attention by many plant research groups.Nevertheless,it is still challenging to conduct large-scale screening of rice panicles to quantify the PNpM^(2)trait due to complex field conditions,a large variation of rice cultivars,and their panicle morphological features.Here,we present Panicle-Cloud,an open and artificial intelligence(AI)-powered cloud computing platform that is capable of quantifying rice panicles from drone-collected imagery.To facilitate the development of Al-powered detection models,we first established an open diverse rice panicle detection dataset that was annotated by a group of rice specialists;then,we integrated several state-of-the-art deep learning models(including a preferred model called Panicle-AI)into the Panicle-Cloud platform,so that nonexpert users could select a pretrained model to detect rice panicles from their own aerial images.We trialed the Al models with images collected at different attitudes and growth stages,through which the right timing and preferred image resolutions for phenotyping rice panicles in the field were identified.Then,we applied the platform in a 2-season rice breeding trial to valid its biological relevance and classified yield production using the platform-derived PNpM^(2)trait from hundreds of rice varieties.Through correlation analysis between computational analysis and manual scoring,we found that the platform could quantify the PNpM^(2)trait reliably,based on which yield production was classified with high accuracy.Hence,we trust that our work demonstrates a valuable advance in phenotyping the PNpM^(2)trait in rice,which provides a useful toolkit to enable rice breeders to screen and select desired rice varieties under field conditions.

Salicylic acid promotes quiescent center cell division through ROS accumulation and down-regulation of PLT1,PLT2,and WOX5

Salicylic acid(SA)plays a crucial role in plant immunity.However,its function in plant development is poorly understood.The quiescent center(QC),which maintains columella stem cells(CSCs)in the root apical meristem and typically exhibits low levels of cell division,is critical for root growth and development.Here,we show that the Arabidopsis thaliana SA overaccumulation mutant constitutively activated cell death 1(cad1),which exhibits increased cell division in the QC,is rescued by additional mutations in genes encoding the SA biosynthetic enzyme SALICYLIC ACID INDUCTION DEFFICIENT2(SID2)or the SA receptor NONEXPRESSER OF PR GENES1(NPR1),indicating that QC cell division in the cad1 mutant is promoted by the NPR1-dependent SA signaling pathway.The application of exogenous SA also promoted QC cell division in wild-type plants in a dose-dependent manner and largely suppressed the expression of genes involved in QC maintenance,including those encoding the APETALA2(AP2)transcription factors PLETHORA1(PLT1)and PLT2,as well as the homeodomain transcription factor WUSCHEL-RELATED HOMEOBOX5(WOX5).Moreover,we showed that SA promotes reactive oxygen species(ROS)production,which is necessary for the QC cell division phenotype in the cad1 mutant.These results provide insight into the function of SA in QC maintenance.

Global achievements in sustainable land management

Identification and development of sustainable land management is urgently required because of widespread resource degradation from poor land use practices.In addition,the world will need to increase food production to meet the nutritional needs of a growing global population without major environmental degradation.Ongoing climate change and its impacts on the environment is an additional factor to consider in identifying and developing sustainable land use practices.The objectives of this paper are to:(1)provide a background to the need for sustainable land management,(2)identify some of its major components,and(3)discuss some examples of sustainable land management systems that are being practiced around the world.Some common components of this type of management are:(1)understanding the ecology of land management,(2)maintenance or enhancement of land productivity,(3)maintenance of soil quality,(4)increased diversity for higher stability and resilience,(5)provision of economic and ecosystem service benefits for communities,and(6)social acceptability.Several examples of sustainable land management systems are discussed to illustrate the wide range of systems that have been developed around the world including agroforestry,conservation agriculture,and precision agricultural systems.Improved technology,allowing for geater environmental measurement and for improved access and sharing of information,provides opportunities to identify and develop more sustainable land management practices and systems for the future.