We evaluated averaging techniques in data processing for the estimation of canopy net photosynthetic rates (Pn) of two cherry tomato plants using a multiple linear regression analysis with variables of aerial environmental factors. Whole canopy Pn and the environmental factors were measured in a high time resolution with a 5-minute interval under a commercial greenhouse by using a novel photosynthesis chamber. We processed the data by using a moving average (MA) and simple average (SA) with several time frames (30-minute, 1-hour, 2-hour). The canopy Pn was expressed as a general linear function of PAR irradiance (I), air temperature (T), relative humidity (RH), vapor pressure deficit (VPD), and CO2 concentration (C). Model accuracy generally increased with longer time frames; however, it can be varied depending on the datasets and the variables used in the models. The 2-hour-SA datasets gave the best accuracy for both 5-variable model (I, T, RH, VPD, C) and 3-variable model (I, VPD, C) with R2 of 0.81 and 0.67, respectively. This study indicates that datasets of 2-hour time frame with simple average are promising to make a practical general linear regression model for the estimation of Pn of cherry tomato by using the high time-resolution Pn data.
The objective of this study was to develop an empirical model for whole-plant net photosynthetic rate (Pn, μmol s-1 per plant) as a function of four essential environmental factors: photosynthetically active radiation (PAR) above the canopy (I, W m-2), air temperature (T, ℃), CO2 concentration (C, μmol mol-1), and vapor pressure deficit (VPD, kPa) by using the dataset of Pn and corresponding environmental factors. To prepare the dataset, we monitored the photosynthesis of mature cherry tomato plants grown in a commercial greenhouse for 15 days in summer with a non-contact, non-intrusive photosynthesis real-time monitoring chamber. Four linear models, namely the general linear model (G-model), linear interaction model (I-model), linear squared model (S-model), and linear interaction-squared model (IS-model), were developed and validated their accuracy. The results suggest that the proposed models successfully simulated the cherry tomato plant's photosynthesis grown in a commercial greenhouse, and IS-model kept relatively higher accuracy regardless of weather conditions. However, to achieve the most accurate Pn estimation is to apply S-model for a sunny day and I-model for a rainy day. These models are prospective for a model-based plant diagnosis to make a judgment whether the current photosynthesis is normal or not.
Forcing culture of witloof chicory (Cichorium intybus L.) is conducted in an enclosed and dark space at a temperature of roughly 15 ℃, and the forcing space is cooled in summer. Temperature control in the forcing space for etiolated head (chicory) production was attempted using natural heat for a period of two years. Etiolated heads were obtained in the hydroponic culture of chicory roots. In 2015, air temperature in the culture room changed to roughly 21 ℃ during the hottest season because of the use of a combination of geothermal and underground water temperatures. In 2016, the average air temperature in the cooling treatment room (cooling) decreased to 16.8 ℃, and the control room (non-cooling) temperature was 22.2 ℃ during the hot season, achieved via geothermal and snow's cold heat. Quantity of cold heat supplied by snow into the culture room was four to five times higher than that of geothermal cold heat, suggesting the importance of snow's cold heat. Tightness of etiolated heads obtained in cooling was better compared to the control during the hot season. These results indicate that chicory forcing culture had been successful in an enclosed space cooled by geothermal and snow's cold heat in summer.
The purpose of this work is to comparatively assess pollen viability of five plant species growing in different areas of the city of Aktobe, Kazakhstan (N 50°18´, W 57°10´). Pollen viability was assessed through iodine staining on the samples of pollen grains harvested between April and June 2017 from 100 plants of 5 species growing in the industrial zones, parks, and along highways: Ulmus laevis Pall., Ulmus pinnato-ramosa Dieck., Acer negundo L., Syringa vulgaris L., Populus tremula L. The minimum percentage of fertile pollen grains that was found in Ulmus laevis species has been detected in samples from the industrial zones, up to 68%. For Ulmus pinnato-ramosa, the minimum proportion of fertile pollen grains was 30%. For Acer negundo and Syringa vulgaris, similar trends were obtained. All plant species except Ulmus laevis (0.42) and Populus tremula (0.37) showed no relationship between the size of pollen grains and the intensity of their color change. Among all plant species under study, two (Ulmus laevis and Populus tremula) had the potential to act as model plant species and bioindicators of urban pollution. All five plant species demonstrated the highest proportion of defective pollen grains in the industrial zones, up 98%.
In this study, we explained the phytohormone profiles associated with various stages of melon fruit growth. This is achieved using melon fruits were obtained 14 to 56 days after flowering (DAF) and grouped into the rind, pulp, and placenta part (including seeds). The peduncle part (including the petiole of about 10 cm in length) was also obtained. Furthermore, using liquid chromatography-mass spectrometry (LC-MS), we quantified simultaneously indole-3-acetic acid (IAA), abscisic acid (ABA), trans zeatin (tZ), isopentenyladenine (iP), jasmonic acid (JA), methyl jasmonate (MeJA), gibberellin1 (GA1) and gibberellin4 (GA4) obtained from various tissues. tZ and iP concentrations increased at 42 DAF in the placenta part but rapidly declined at 56 DAF. The GA4 concentration was similar in the placenta part, the rind, and flesh within the fruit, but changed differently in the peduncle part outside the fruit, rapidly increasing to 28 DAF and continuing to decrease thereafter. ABA concentration in the placenta part continued to increase with the progress of fruit growth. In the rind, the concentrations of JA and MJA were generally high. In conclusion, our results revealed an endogenous plant hormone profile in grape fruit growth.
Strawberry (Fragaria × ananassa Duch.) is a rich source of diverse antioxidants associated with health benefits. However, the interactions of antioxidants with plant growth and photosynthetic performance have not been investigated in the strawberry fruit. This study aimed to visually identify the interactions of antioxidant compounds with plant growth, photosynthetic performance, and agronomic quality in commercially grown strawberry on three farms during a 2-month period using correlation network analysis. Growth and photosynthetic performance-related parameters showed variations between seasons and among farms, whereas antioxidant compounds showed only seasonal variations. Additionally, the total polyphenol content and antioxidant activity showed a negative correlation with ten and seven leaf photosynthetic performance parameters, respectively, but no correlation with any of the growth parameters. By contrast, ascorbic acid (ASA) and total ASA were correlated with two photosynthetic performance parameters and three plant growth parameters. These results suggest that ASA exhibits different interactions with the total polyphenol content and antioxidant activity. In addition, leaf thickness and several photosynthetic performance parameters were key factors of the interaction of antioxidant compounds. Overall, our results indicate that correlation network analysis provides useful information to enhance the level of antioxidant compounds in strawberry.
Tomato (Solanum lycopersicum L.) intumescence severely affects tomato plants and thereby crop yields. In this study, we investigated the differences in intumescence between varieties. We assessed the shoot:root (S/R) ratio and incidence of intumescence in seedlings of 12 tomato varieties subjected to sudden increases in ambient humidity and soil moisture. The S/R ratio and severity of intumescence injury were positively correlated. Next, three tomato varieties with different S/R ratios and intumescence incidence were assessed. Changes in xylem pressure potential of seedlings occurred in response to a changing water environment in a controlled environment chamber, i.e., from a dry condition (50% relative humidity, no irrigation) to a wet condition (90% relative humidity, sub-irrigation). The xylem pressure potential decreased under dry conditions in relation to the S/R ratio and intumescence incidence but increased rapidly after exposure to wet conditions. Tomato varieties with large S/R ratios showed large changes in their water potential in response to changes in the surrounding water environment, and it is thought that cells are more likely to rupture when water potential increases after a transition from dry to wet conditions.