Morphophysiological aspects of ornamental sunflowers cultivated in different growing seasons under semi-arid conditions

ABSTRACT Knowledge of how climatic conditions affect plant morphophysiology is essential for understanding how to manage the growth cycles of different crops. The aim of this study was to evaluate the effects of the growing seasons in a semi-arid area on the morphophysiological variables of ornamental sunflower plants. The experiment was carried out in a randomized block design in a split-plot arrangement with four replicates. Six cultivars (‘Bonito de Outono Sortido’, ‘Sol Noturno’, ‘Sol Vermelho’, ‘Jardim Amarelo Alto’, ‘Girassol F1 Sunbright Supreme’ and ‘Girassol F1 Vincents Choice’) were evaluated in the main plots and two different growing seasons (GS) in the subplots (GS1 - warm climate and GS2 - mild climate). Evaluations of gas exchange, chlorophyll indices, and leaf surface area were carried out at the reproductive stage (R5.5). The cultivation of ornamental sunflowers in semi-arid regions was significantly affected by the growing season. Changes in gas exchange variables and the morphophysiology of ornamental sunflower plants in the two growing seasons reflected the high phenotypic plasticity characteristic of this species. The cultivation of ornamental sunflowers under semi-arid conditions in the growing season, when air temperature and solar radiation are high, could be limited due to elevated transpiration rates. Therefore, it is recommended that they are grown mainly during the moderate climatic season in semi-arid regions.

Ecophysiological Crop Modelling Combined with Genetic Analysis Is a Powerful Tool for Ideotype Design

Improving the grain yield of crops in both favourable and stressful environments is the main breeding objective required to ensure food security. In this review, I outline a genotype-to-phenotype approach that exploits the potential values of quantitative genetics and process-based crop modelling in developing new plant types with high yields. The effects of quantitative trait locus (QTL), for traits typically at the single-organ level over a short time scale, were projected for their impact on crop growth during the whole growing season in the field. This approach can provide more markers for selection programmes for specific environments whilst also allowing for prioritization. Crop modelling is thus a powerful tool for ideotyping under contrasting conditions, i.e., use of single-environment information for predicting phenotypes under different environments.

Anatomical adjustment of mature leaves of sycamore maple (Acer pseudoplatanus L.) to increased irradiance

Trees regenerating in the understory respond to increased availability of light caused by gap formation by undergoing a range of morphological and physiological adjustments. These adjustments include the production of thick, sun-type leaves containing thicker mesophyll and longer palisade cells than in shade-type leaves. We asked whether in the shade-regenerating tree Acer pseudoplatanus, the increase in leaf thickness and expansion of leaf tissues are possible also in leaves that had been fully formed prior to the increase in irradiance, a response reported so far only for a handful of species. We acclimated potted seedlings to eight levels (from 1 to 100%) of solar irradiance and, in late summer, transferred a subset of them to full sunlight. Within 30 days, the shaded leaves increased leaf mass per area and became thicker mostly due to elongation of palisade cells, except for the most shaded individuals which suffered irreversible photo-oxidative damage. This anatomical acclimation was accompanied by partial degradation of chlorophyll and a transient decline in photosynthetic efficiency of PSII (Fv/FM). These effects were related to the degree of pre-shading. The Fv/FM recovered substantially within the re-acclimation period. However, leaves of transferred plants were shed significantly earlier in the fall, indicating that the acclimation was not fully effective. These results show that A. pseudoplatanus is one of the few known species in which mature leaves may re-acclimate anatomically to increased irradiance. This may be a potentially important mechanism enhancing utilization of gaps created during the growing season.

Plant Phenology and Its Anthropogenic and Natural Influencing Factors in Densely Populated Areas During the Economic Transition Period of China

As a sensitive, observable, and comprehensive indicator of climate change, plant phenology has become a vital topic of global change. Studies about plant phenology and its responses to climate change in natural ecosystems have drawn attention to the effects of human activities on phenology in/around urban regions. The key factors and mechanisms of phenological and human factors in the process of urbanization are still unclear. In this study, we analyzed variations in xylophyta phenology in densely populated cities during the fast urbanization period of China (from 1963 to 1988). We assessed the length of the growing season affected by the temperature and precipitation. Temperature increased the length of the growing season in most regions, while precipitation had the opposite effect. Moreover, the plant-growing season is more sensitive to preseason climate factors than to annual average climate factors. The increased population reduced the length of the growing season, while the growing GDP increased the length of the growing season in most regions (8 out of 13). By analyzing the impact of the industry ratio, we found that the correlation between the urban management of emerging cities (e.g., Chongqing, Zhejiang, and Guizhou) and the growing season is more significant, and the impact is substantial. In contrast, urban management in most areas with vigorously developed heavy industry (e.g., Heilongjiang, Liaoning, and Beijing) has a weak and insignificant effect on plant phenology. These results indicate that different urban development patterns can influence urban plant phenology. Our results provide some support and new thoughts for future research on urban plant phenology.

Impact of Extreme Climate on Orage Farming Surjan System in Botola

The determining factor for the success of agricultural cultivation in tidal swampland is water availability, which fluctuates throughout the plant's growth. The availability of water for oranges has a significant role in the final production of the product. In Indonesia, there are three types of rain patterns with variations in the growing season related to water availability: the rainy season between October and March and the dry season between April and September. Climate extremes such as drought (El-Niño) and wetness (La-Niña) fluctuate dynamically, impact shifts at the beginning and end of the growing season, and hurt citrus crop productivity. Therefore, an analysis of rice planting time in tidal swampland in Barito Kuala under extreme climatic events was carried out. The research was conducted in September – December 2020 with the survey method. The data was dug in-depth on the research respondents: citrus farmers, fruit traders, and related agencies. The number of samples was 90 people (45 male farmers and 45 female farmers). Two different villages were surveyed in each sub-district according to the type of tidal land, namely Marabahan sub-district (SP1 village and SP2 village), type A, Mandastana (Karang Indah village and Karang Bunga village) type B, and Cerbon sub-district. (Village of Simpang Nungki and Sungai Kambat) Type C. Planting time in tidal land begins after the amount of rainwater is sufficient to dissolve the iron content in the water. The probability of an El-Niño occurrence with an intensity of 1, 2, 3, and 4 years has the highest frequency of occurrence—respectively 3, 3, 5, and 3 times with probability around 16.7% to 27.8%. Meanwhile, La-Nia with an intensity of once a year with the highest frequency eight times with a 40.0% chance. La-Nia events coexist with El-Nio 15 times, and generally, El-Nio precedes La-Nia by about 44%. The cropping pattern in tidal swampland shows high resistance to climate change. Namely, the planting time has not changed much for decades under different climatic conditions.

The Influence of the Agroecological Resources of Crimea on thePrimary and Secondary Metabolites of AligoteGrapes

This research focused on examining the interrelationships between the natural conditions for growing grapes, as well as the quantitative and qualitative characteristics of the harvest. These are important criteria for the scientifically grounded selection of a territory for planting a vineyard, selecting varieties and determining the use of the resulting products. The characteristics of six model vineyards of the Aligote cultivar, located in various natural zones and viticultural regions of the Crimea, were analyzed. The values of climatic indicators were calculated, including the growing degree days above 10∘C (∑Т ∘С10), growing degree days above 20∘C (∑Т ∘С20), Huglin index, Winkler index, average growing season temperature, average September temperature, ratio ∑Т ∘С20/∑Т ∘С10,total precipitation during the year, total precipitation during the growing season, total precipitation in September, and Selyaninov hydrothermal coefficient. These were calculated usinggeoinformation and mathematical modeling for the locations of the analyzed vineyards. The content of the primary metabolites (total sugars, titrated acids and calculated indicators based on them) and secondary metabolites (phenolic components, oxidase activity) of grapes from the model vineyards were analyzed. The range of variation in the studied indicators within the analyzed territories was calculated, and the nature and magnitude of the relationships between the indicators were revealed. A cluster analysis of the analyzed vineyards was carried out and clusters were distinguished according to the degree of similarity in climatic parameters, as well as the content of the primary and secondary metabolites of the grapes. Keywords: grapes, agroecological factors, primary and secondary grape metabolites, ampeloecological zoning, terroir

Effects of Rainfall on the Characteristics of Soil Greenhouse Gas Emissions in the Wetland of Qinghai Lake

Niaodao, a lakeside wetland, was used as the focus of this study to investigate the effect of rainfall changes on the greenhouse gas fluxes of wetland ecosystems. Wetland plots with different moisture characteristics (+25%, −25%, +75%, and −75% rainfall treatments and the control treatment (CK)) were constructed to observe in situ field greenhouse gas emissions at 11:00 and 15:00 (when the daily mean values were similar) in the growing season from May to August 2020 by static chamber–gas chromatography and to investigate the responses of wetland greenhouse gases to different rainfall treatments. The results showed the following: (1) The carbon dioxide (CO2) flux ranged from −49.409 to 374.548 mg·m−2·h−1. The mean CO2 emission flux was greater at 11:00 than at 15:00, and the +25% and +75% treatments exhibited substantially higher CO2 emissions. In addition, the CO2 flux showed a small peak at the beginning of the growing season when the temperature first started to rise. All treatments showed the effect of the CO2 source, and their effects were significantly different. (2) The methane (CH4) flux ranged from −213.839 to 330.976 µg·m−2·h−1 and exhibited an absorption state at 11:00 and an emission state at 15:00. The CH4 emission flux in August (the peak growing season) differed greatly between treatments and was significantly negatively correlated with the rainfall amount (p < 0.05). (3) The nitrous oxide (N2O) flux ranged from −10.457 to 16.878 µg·m−2·h−1 and exhibited a weak source effect throughout the growing season, but it was not significantly correlated with soil moisture; it was, however, negatively correlated with soil temperature. (4) The different treatments resulted in significant differences in soil physical and chemical properties (electrical conductivity, pH, total soil carbon, and total soil nitrogen). The rainfall enhancement treatments significantly improved soil physical and chemical properties.

Different Radial Growth Responses to Climate Change of Three Dominant Conifer Species in Temperate Forest, Northeastern China

We conducted dendroclimatological study on three dominant conifer tree species, Pinus koraiensis, Larix olgensis, and Picea jezoensis, in northeastern China for a better understanding of climate change impacts on temperate forest growth, by discussing the radial growth relationships of these tree species and projecting their radial growth trends under the future climate change scenarios. Based on the tree-ring samples collected from the upper altitude of Changbai Mountain, ring width chronologies were built to examine the growth relationships, and regression equations were established to project the future growth of the species under future climate change projected by the five general circulation models (GCMs) and four representative concentration pathway (RCP) scenarios. Although both temperature and precipitation showed varying degrees of relationships with growth of these three tree species, the limiting climate factors were species-specific. The tree-ring growth of P. koraiensis was limited by the summer temperature and precipitation at the end of growth, namely, significant positive correlations with the current July temperature and the previous September precipitation. Growth of L. olgensis was limited by the temperature before growing season, for its chronology was negatively correlated with the current February and previous December temperature (p &lt; 0.05). The climatic conditions before and after growing season seemed to be the limiting factors of P. jezoensis growth, which was negatively correlated with the current February to April temperature and the current September temperature (p &lt; 0.05), and positively correlated with the current August precipitation (p &lt; 0.05). Under the gradual increasing of temperature predicted by the five GCMs and four RCP scenarios, the radial growth of P. Koraiensis will relatively increase, while that of L. olgensis and P. jezoensis will relatively decrease comparing to the base-line period (1981–2010). The specific growth–climate relationships and the future growth trends are species dependent. P. Koraiensis was the more suitable tree species for the forestation to maintain the sustainable forest in Changbai Mountain.