Plant Water Content Research Articles

Evaluation of the Effect of ACC Deaminase and Exopolysaccharides Producing Bacteria in Maize (Zea mays) under Heat Stress

Heat stress or global warming is a continuous temperature fluctuation that affects the environment and damage plant tissues because of the hormonal imbalances in plants. Yield losses resulting from heat stress are a major threat to global food security. Plant growth-promoting bacteria (PGPB) may be utilized to lessen this loss in yield. PGPB containing aminocyclopropane-1-carboxylic acid (ACC) deaminase activity can enhance plant growth that various abiotic stresses inhibit. This work was conducted to evaluate the effect of ACC deaminase and exopolysaccharides producing bacteria on maize plants grown under heat stress. The stressed plants were kept at 45 °C, while non-stressed plants were grown at a temperature of 28 - 35 °C. In 45 days of the growing period under heat stress, the plant growth and activities were decreased, however, in the presence of PGPB (isolated from soil and plant tissues in Muzaffagarh, Pakistan) containing ACC deaminase activity, the plant activities and biomass were increased compared to their respective control. The ACC deaminase-producing bacteria played a significant role by enhancing the physiological activities of the plants like chlorophyll a and b, carotenoid pigments, and proline content. Enzymatic activities like superoxide dismutase (81 %), peroxidase (57.8 %), and catalase (50.27 %) were increased. The relative water content of the maize plants was increased in Treatment one (T1) with 300, and 200 % for non-heat and heat, respectively, while the control was having 220, and 200 % for non-heat and heat, respectively. Soluble sugar content was improved with T1 having the highest values (4,000 and 5,700 g/mol) for heat and non-heat, respectively. The control was having 900, and 2300 g/mol for heat and non-heat, respectively. The application of ACC deaminase-producing bacteria on maize can help to overcome the adverse effects of heat stress and help the plant to survive under stress condition.
 HIGHLIGHTS
 
 Heat stress is a continuous temperature fluctuation that affects the environment and damage plant tissues because of the hormonal imbalances in plants, and yield losses resulting from heat stress are a major threat to global food security
 This research work was carried out to assess the effect of ACC deaminase and exopolysaccharides producing bacteria on maize plants grown under heat stress
 The use of ACC deaminase-producing bacteria on maize can help to overcome the adverse effects of heat stress and help the plant to survive under stress condition
 
 GRAPHICAL ABSTRACT

Action of silicon on the activity of antioxidant enzymes and on physiological mechanisms mitigates water deficit in sugarcane and energy cane plants

Production of sugarcane and more recently of energy cane strengthen renewable bioenergy production capacity. However, droughts resulting from climate change have limited the production of these crops. One of the strategies to attenuate water deficit damage in these crops is the use of silicate, which contributes to plant physiology. This strategy is likely to increase water use efficiency, thus promoting crop sustainability. Notwithstanding, studies on this issue are still incipient. This study assesses whether Si applied via fertigation and foliar spraying in the seedling production phase and as a complement after seedling transplanting to the soil is efficient in attenuating water deficit in sugarcane and energy cane. The study further elucidates physiological and biochemical mechanisms involved in this process. For this, the authors conducted two experiments: one with sugarcane and the other with energy cane. Treatments were arranged in randomized blocks with 5 replications, in a 2 × 2 factorial scheme. Factors consisted of the absence (-Si) and presence of Si (+ Si) applied via fertigation and foliar spraying; and two water regimes: 70% (without water deficit) and 30% (severe water deficit) of the soil water retention capacity. Silicon was supplied during the formation phase of presprouted seedlings and during the transplanting of seedlings to pots filled with samples of Entisol (Quartzipsamment). In these pots, water regimes were induced from 7 to 160 days after transplanting. Severe water deficit reduced the water content and water potential of plants. This situation induced oxidative stress and impaired gas exchange and photosynthetic water use efficiency, reducing plant growth. Silicon supply via fertigation in association with foliar spraying in the seedling formation phase with complementation after transplanting was efficient in increasing Si accumulation in the plants. Silicon was effective in attenuating severe water deficit damage up to initial culm formation through mechanisms that maintain water and physiological balance by favoring the antioxidant defense system in sugarcane and energy cane plants.

Long-term snow alters the sensitivity of nonstructural carbohydrates of Syntrichia caninervis to snow cover: Based on a 7-year experiment.

The dynamics of nonstructural carbohydrates (NSC) profoundly affect productivity and ecological adaptability to adversity in plants. Global warming induced the frequent occurrence of extreme precipitation events that altered the winter snow pattern in deserts. However, there is a lack of understanding of how desert mosses respond to long-term snow cover change at the NSC level. Therefore, in this study, long-term (7-years) winter snow removal (-S), ambient snow (CK), and double snow (+S) experiments were set in the field to investigate the content of NSC and its component in Syntrichia Caninervis. Our results showed that changes in snow depth, snow years, and their interaction significantly affected NSC and its component of Syntrichia caninervis. Compared to snow removal, NSC, soluble sugar, and starch significantly decreased with the increasing snow depth. The ratio of soluble sugar to starch significantly increased, while NSC and soluble sugar gradually returned to the normal level with an increase in snow years. It is worth mentioning that snow removal significantly reduced the soluble sugar to starch ratio compared to ambient snow depth, whereas the double snow experiment significantly increased the ratio of soluble sugar to starch during winter. This indicated an obvious trade-off between carbon utilization and carbon storage in Syntrichia caninervis. Snow removal stimulated Syntrichia caninervis to store sufficient carbon sources by starch accumulation for its future growth, while double snow promoted its current growth by soluble sugar accumulation. The variance in decomposition showed that soil physical and chemical properties, snow cover, and their interaction explained 83% of the variation in NSC and its components, with soil and plant water content, pH, and electrical conductivity (P-WC, S-WC, S-pH, and S-EC) as significant predictors. This highlights that snow indirectly affected NSC and its component contents by changing soil physical and chemical properties; however, long-term changes in snow cover could slow down its sensitivity to snow.

An Assessment of Moringa (Moringa oleifera L.) Seed Extract on Crop Water Productivity and Physico-Biochemical Properties of Cancer Bush (Sutherlandia frutescens L.) under Deficit Irrigation

Water deficit is a main abiotic stress limiting the cultivation of many plants including cancer bush (Sutherlandia frutescens L.), which is a traditional medicinal plant used to treat various diseases such as tuberculosis, cancer, diabetes and asthma. Natural plant growth hormones are a cost-effective and environmentally friendly alternative to synthetic growth regulators for plant production under favourable or adverse conditions. Thus, the current study investigated the biostimulant effect of moringa (Moringa oleifera L.) seed extract (MSE) on physiological and biochemical attributes, including crop water productivity (CWP) of cancer bush grown under deficit irrigation. The 2% MSE was foliar-sprayed to cancer bush plants subjected to full (100% of soil water holding capacity (SWHC)) and deficit irrigation (DI) (80, 60 and 40% of SWHC) in a pots experiment which was conducted and repeated twice consecutively in a tunnel. Plants that were not treated with MSE were considered as control. The results on water-deficit stress showed that the performance of cancer bush was significantly reduced in terms of growth and yield attributes, CWP, as well as physico-biochemical properties. Nevertheless, the foliar application of MSE on water-stressed plants effectively enhanced growth and yield characteristics, CWP, leaf photosynthetic pigments (chlorophyll “a”, chlorophyll “b”, total chlorophylls and total carotenoids), antioxidant activity (2′-Diphenyl-1-picrylhydrazyl and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid), relative water content (RWC) and membrane stability index (MSI) of cancer bush plants compared to respective controls. Therefore, the 2% MSE application was effective in mitigating negative impact of drought stress in cancer bush plants by maintaining higher RWC, MSI, CWP and biochemical attributes.

The combined use of a plant growth promoting Bacillus sp. strain and GABA promotes the growth of rice under salt stress by regulating antioxidant enzyme system, enhancing photosynthesis and improving soil enzyme activities

Salt stress poses a global challenge for agriculture, crop growth, and food production. In this study, a strain of rhizobacteria with both plant growth-promoting (PGP) traits and salt tolerance was isolated. The strain was identified as Bacillus pumilus via 16 S rDNA sequencing and was named B. pumilus JIZ13. This strain had the potential to solubilize phosphates and produce 1-aminocyclopropane-1-carboxylic acid deaminase, siderophores, and indole-3-acetic acid. After 35 days of salt stress exposure, the root length, plant height, dry weight, fresh weight, and relative water content of rice plants inoculated with strain JIZ13 were significantly higher than those without inoculation. Interestingly, the PGP properties of strain JIZ13 were significantly improved by the exogenous addition of gamma-aminobutyric acid (GABA). Moreover, GABA also enhanced the growth and development of rice plants under salt stress by providing substrates for the tricarboxylic acid cycle. Furthermore, the synergistic roles of GABA and strain JIZ13 in mitigating the damage caused by salt stress in rice plants was investigated. The results showed that the co-application of GABA and JIZ13 significantly increased photosynthetic efficiency, chlorophyll accumulation, antioxidant levels, levels of osmotic adjustment substances, and biomass of rice under salinity stress. In addition, the activities of urease, protease, invertase, and catalase enzymes in soil significantly improved under the combination of strain JIZ13 and GABA and increased by 39.65%, 36.88%, 70.21%, and 65.23%, respectively, compared to those without rhizobacterial and GABA additions. The enhancement of these four soil enzyme activities might thus improve soil quality and increase root elongation and biomass in rice plants. The results of this study provide the first evidence that PGP-rhizobacterial strain JIZ13 along with GABA can attenuate the negative effects of salt stress in rice plants.

StJAZ1-like mediated root architecture plays critical roles in drought susceptibility in potato

Unlike other major crops, the potato root system is formed by adventitious roots in tuber-grown plants, and considered inefficient. Root architectural traits define plant performance and yield, particularly under the restricted water level. The phytohormones are the major players in root development. But the phytohormones which regulate adventitious root formation in potato plant and consequently contribute to drought tolerance, are not well studied. Here, we have now found that StJAZ1-like, a suppressor in jasmonic acid (JA) signaling, enhances drought susceptibility by attenuating adventitious root formation in potato. The StJAZ1-like-overexpressing (StJAZ1-like ox) potato plants were more sensitive to drought compared to wild type (WT) plants. Grafting experiments showed that the increased drought susceptibility was due to the attenuated root architecture. In addition, overexpression of StJAZ1-like caused a decrease in relative leaf water content in potato plants under drought stress. Under the drought stress, malondialdehyde (MDA) content was significantly higher, while antioxidant enzymes like superoxide dismutase (SOD) and peroxidase (POD) activities were significantly less in StJAZ1-like ox plants. Further, transcriptome profiling analysis of the root tips revealed that the expression levels of three tandem-arranged small auxin upregulated RNA (SAUR) genes were significantly upregulated in StJAZ1-like ox plants. StJAZ1-like ox plants exhibited an enhanced auxin response, suggesting StJAZ1-like modulates auxin responses. Taken together, our results suggested StJAZ1-like plays critical roles in root architecture and drought susceptibility in potato.

Salinity Effect on Plant Growth Parameters and Fruit Bioactive Compounds of Two Strawberry Cultivars, Coupled with Environmental Conditions Monitoring

Salinity stress is one of the most vital abiotic stresses, impairing the productivity of crops in both irrigated and dry areas. A pot experiment was carried out in a greenhouse environment, aiming to examine the relevant tolerances and evaluate the effect of salinity stress on plant growth, fruit physiological, and quality traits of two strawberry cultivars, Camarosa and Rociera. The plants were irrigated with water with electrical conductivity (EC) of 0.4 dS m−1 (control), or with a salt solution with either ECs 2 dS m−1 (moderate salt stress) or 4 dS m−1 (elevated salt stress). Furthermore, several meteorological parameters, as well as soil moisture, were monitored inside the greenhouse. The results showed that salinity induced osmotic stress, water deprivation, and toxic effects, affecting the growth parameters and yield of both cultivars. The elevated salt stress imposed a negative impact on Rociera’s fruits carbohydrates, organic acids, and anthocyanins, while the antioxidant capacity increased. However, Rociera exhibited high total yield/plant and total yield even under elevated salt stress compared to Camarosa. Camarosa plants grown under high salt levels presented low salinity tolerance index, plant water content, and growth parameters. The fruits exhibited low fresh weight but high sweetness index and antioxidant power. An accumulation of soluble sugars under saline conditions, especially sucrose, was also detected in cv. Camarosa fruits when compared to Rociera. Therefore, the two cvs. exhibited a different pattern of response to salinity stress concerning their physiological, biochemical and nutritional characteristics; however, either could be an interesting alternative for cultivation in areas where a slight salinization of the water or soil imposes a limitation on the rather salt-sensitive crops. Agronomic and biochemical evaluation of salinity stress coupled with monitoring of greenhouse microclimatic conditions will lead to a better understanding of the effects on plant growth and quality characteristics, enhancing the productivity of strawberry cultivars, especially under salt-affected environments.

Physiological studies on eggplant (Solanum melongena) grown under drought conditions

Field experiment was conducted during the two growing seasons of 2019 and 2021, at Dokki region, El-Giza Governorate, Egypt, in order to investigate the effect of deficit irrigation (DI) treatments: 100% (control), 70% and 50% of ETo (Reference evapotranspiration) and two irrigation systems: Surface drip irrigation (SDI) and Subsurface irrigation (SSI)porous pipe (20.0cm soil depth) on vegetative growth, chemical constituents, fruit yield and quality of eggplant plants (Cultivars : “Classic” “Swad Eleil”). Results revealed that, DI treatments significantly decreased the vegetative growth, total yield ,marketable yield, leaf relative water content (LRWC) and membrane stability index (MSI) of eggplant plants, compared to control treatment (100% ETₒ). While, water stress treatments improved leaves proline content, alkaloids and irrigation water use efficiency (IWUE). Using SSI (porous pipe) system significantly increased plant height, fresh weight, total yield, marketable fruit yield of eggplant, LRWC and MSI, “Classic” cv had the highest total yield and total marketable yield under the subsurface irrigation system compared to “Swad El-Layl”cv. Regarding, the effect of interaction between DI treatments and irrigation systems, the results illustrated that application of irrigation water with 100% ET0 by SSI system produced the highest significant values of vegetative growth, fruit yield.

Endophytic Candida membranifaciens from Euphorbia milii L. Alleviate Salt Stress Damages in Maize

Fungal endophytes are not widely known for their role in bioactive metabolite production and salinity stress alleviation in different crop plants. Presently, we investigated the salt stress (NaCl, KCl, and H2SO4) mitigation capabilities of fungal endophyte Candida membranifaciens (FH15) isolated from Euphorbia milii L. The pure culture filtrate (CF) of C. membranifaciens revealed siderophore production and solubilization of phosphate, with high levels of indoleacetic acid (IAA: 35.8µg/mL), phenolics (70 µg/mL), and flavonoids (50 µg/mL) by using a UV spectrophotometer. The LC/MS analysis of the CF showed different phenols and flavonoids that were identified as Salicylic acid, Baicalein, Aconitic acid, Feruloylquinic acid, Coniferyl aldehyde hexoside, Pentose, Chlorogenic acid, Myricetin, Propoxyphene, and Amino-flunitrazepam. Inoculation of maize seedlings with C. membranifaciens significantly (p = 0.05) enhanced the fresh and dry biomass, carotenoid, and chlorophyll contents under 100 mM salt stress conditions. Similarly, the catalase, peroxidase activity, phenols, proline flavonoids and relative water contents (RWC) of the maize plants were enhanced. More interestingly, the inoculation of C. membranifaciens on maize revealed a higher endogenous IAA level as compared to non-inoculated control plants. Endophyte C. membranifaciens inoculation on maize seedlings under salt stress revealed a 20.87% and 16.60% increase in fresh and dry biomass, as well as significantly enhanced root shoot length and allied growth attributes, in addition to an alleviation of the adverse effects of salinity stress. Conclusively, endophytic C. membranifaciens significantly enhanced the growth attributes of maize and mitigated the adverse effects of salinity stress. Such endophytic fungal strain could be used for further field trails to enhance agricultural productivity and facilitate sustainable agricultural practices.

Interactions between hydrogen sulphide and rhizobia modulate the physiological and metabolism process during water deficiency-induced oxidative defense in soybean.

Hydrogen sulphide (H2 S), a new gas signal molecule, participates in the regulation of various abiotic stresses in plants. However, how the tandem working of H2 S and rhizobia affects the adaptation of soybean to water deficiency is still unclear. In this study, we investigated the adaptation mechanism of H2 S and rhizobia in soybean to water deficiency. Our results revealed that H2 S and rhizobia jointly enhanced the leaf chlorophyll content and relative water content in plants, and caused an increase in the biomass of soybean seedlings under water deficiency. Besides, in the absence of water, H2 S enhanced the biomass by affecting the number of nodules and nitrogenase activity during vegetative growth. The expression of nodulation marker genes including early nodulin 40 (GmENOD40), ERF required for nodulation (GmERN) and nodulation inception genes (GmNIN1a, GmNIN2aand GmNIN2b) were upregulated by H2 S and rhizobia in the nodules. Moreover, the combined effect of H2 S and rhizobia was proved to affect the enzyme activities and gene expression level of antioxidants, as well as osmotic protective substance content and related gene expression levels under water deficiency in soybean seedlings. In addition, the metabolomic results suggested that the combined effect of H2 S and rhizobia remarkably promoted the contents of lipids and lipid-like molecules. Our results indicated that H2 S and rhizobia synergistically reduced the oxidative damage caused by water deficiency through increasing the accumulation of metabolites and strengthening the plant antioxidant capacity.

Vegetation growth status as an early warning indicator for the spontaneous combustion disaster of coal waste dump after reclamation: An unmanned aerial vehicle remote sensing approach.

Spontaneous combustion of coal waste dumps is a serious threat to the ecological environment and the safety of mining areas. Even after land reclamation and ecological restoration, such spontaneous combustion activities are still active. Achieving early warning of spontaneous combustion is necessary to protect the reclaimed ecosystem and reduce environmental pollution, but it has not yet been well studied. To this end, this study proposed a spatial analysis method to achieve early warning spontaneous combustion of coal waste dump after reclamation by integrating unmanned aerial vehicle (UAV) and vegetation (Medicago sativa/alfalfa) growth status. The experiment was implemented in two slope areas (Areas I and II) of a coal waste dump after reclamation in Shanxi province, China, which were under threat of spontaneous combustion. Three alfalfa growth parameters, aboveground biomass (AGB), plant water content (PWC), and plant height (PH) of the study area, were estimated from UAV imagery features and used to assess the spontaneous combustion risk. Then, soil deep temperature points (25cm depth) distributed evenly in the study area were collected to determine the underground temperature situation. It was found that the UAV-derived rededge Chlorophyll index (CIrededge), canopy temperature depression (CTD), and canopy height model (CHM) achieved a better estimation of alfalfa AGB (R2=0.81, RMSE=99.2g/m2, and MAE=74.9g/m2), PWC (R2=0.68, RMSE=3.9%, and MAE=3.2%), and PH (R2=0.77, RMSE=9.79cm, and MAE=7.68cm) of the study area, respectively. We also observed that three alfalfa parameters were highly correlated with the soil deep temperature, but differed in degree (R2=0.46-0.81). Furthermore, they were consistent with the soil deep temperature in spatial distribution and could reveal the change direction of underground temperature, which will help us to detect those potential spontaneous combustion areas. These results indicated that vegetation is a prior indicator to the changes in underground temperature of coal waste dump. We believed that UAV can be an effective environmental management tool for the initial assessment of spontaneous combustion risk of coal waste dump after reclamation.

Effects of Different Salt Applications on Ion and Physiological Analysis in Lettuce

The increase in salinization in agricultural lands adversely affects crop production. In particular, yield and quality losses occur in many vegetables such as lettuce, which are grown and consumed in every season. Realizing these losses in crop production, more careful fertilization and agricultural practices should be done. Yedikule lettuce seeds were used in the study to draw attention to these negative aspects. The study, which was carried out for two years, was designed with 0, 50, 100 and 150 mmol doses of salt according to a randomized parcel design with three replications and four pots in each replicate. Each 2-liter pot was filled with a 2:1 ratio of peat: perlite mixture and the study was carried out with 2 lettuces in each pot. As a result of the study, when the plant weight data of the first year and the second year are examined, it is seen that the weight loss of lettuce plants and damage to the plants increase when the salt doses increase. It was observed that the highest plant weight loss occurred at 150 mmol salt dose. Membrane damage index in lettuce leaves was observed to increase as the salt dose increased. It was observed that the leaf water rate decreased with increasing salt doses. Membrane damage index and leaf water content of lettuce plants were more negatively affected at 150 mmol of salt in both years. Potassium, calcium and magnesium contents in lettuce leaves were statistically decreased due to increasing salt doses in both years, while sodium content increased with increasing salt doses and the highest sodium content was observed at 150 mmol dose in both years. As seen in these results, increasing salt doses reduce the nutrient content and plant weight in lettuce plants and cause physiological damage to the plant, resulting in yield and quality loss.

Comparison of UAV RGB Imagery and Hyperspectral Remote-Sensing Data for Monitoring Winter Wheat Growth

Although crop-growth monitoring is important for agricultural managers, it has always been a difficult research topic. However, unmanned aerial vehicles (UAVs) equipped with RGB and hyperspectral cameras can now acquire high-resolution remote-sensing images, which facilitates and accelerates such monitoring. To explore the effect of monitoring a single crop-growth indicator and multiple indicators, this study combines six growth indicators (plant nitrogen content, above-ground biomass, plant water content, chlorophyll, leaf area index, and plant height) into the new comprehensive growth index (CGI). We investigate the performance of RGB imagery and hyperspectral data for monitoring crop growth based on multi-time estimation of the CGI. The CGI is estimated from the vegetation indices based on UAV hyperspectral data treated by linear, nonlinear, and multiple linear regression (MLR), partial least squares (PLSR), and random forest (RF). The results are as follows: (1) The RGB-imagery indices red reflectance (r), the excess-red index (EXR), the vegetation atmospherically resistant index (VARI), and the modified green-red vegetation index (MGRVI), as well as the spectral indices consisting of the linear combination index (LCI), the modified simple ratio index (MSR), the simple ratio vegetation index (SR), and the normalized difference vegetation index (NDVI), are more strongly correlated with the CGI than a single growth-monitoring indicator. (2) The CGI estimation model is constructed by comparing a single RGB-imagery index and a spectral index, and the optimal RGB-imagery index corresponding to each of the four growth stages in order is r, r, r, EXR; the optimal spectral index is LCI for all four growth stages. (3) The MLR, PLSR, and RF methods are used to estimate the CGI. The MLR method produces the best estimates. (4) Finally, the CGI is more accurately estimated using the UAV hyperspectral indices than using the RGB-image indices.

Comparison of various approaches for estimating leaf water content and stomatal conductance in different plant species using hyperspectral data

Water deficit stress is a frequent phenomenon that inhibits plant growth. This study explores the performance of hyperspectral data for estimating the leaf water content of ten tree species under different water conditions. The three most commonly used leaf water content indicators (relative water content, equivalent water thickness, and fuel moisture content) and stomatal conductance were assessed using narrow-band indices (single band, band ratio, band subtraction, and band difference) and multivariate analyses (partial least squares regression (PLSR), support vector regression, artificial neural network, and random forest) within the 350–2500 nm spectral reflectance range. The results indicated that the best bands and band combinations were mainly concentrated in the short-wavelength infrared region, which is sensitive regarding plant water content. Compared to a single band, dual-band indices exhibited better overall performance among the four kinds of indices. Multivariate analyses are more accurate than narrow-band indices. Among these, PLSR is the most robust and can be considered the optimal technique for predicting the water content of all tree species, except for conifer species. However, accurately predicting stomatal conductance is difficult to predict using these methods. This study shows that the PLSR model can accurately estimate leaf water content in multiple tree species, and hyperspectral technology, such as hyperspectral remote sensing, has potential regarding the estimation of leaf water content.

RESPON BEBERAPA SIFAT FISIKA TANAH ALUVIAL PADA KOMBINASI KOMPOS SAMPAH KOTA DAN PUPUK KANDANG SAPI SETELAH DITANAMI PAKCOY

Alluvial soil in this study is a vertic endoaquepts paddy soil type, which is an alluvial paddy soil with a wide distribution in the Pantura area, West Java, originating from a long river deposition system with various types of erosion materials. This soil has a high mineral content of easily weathered sand, especially feldspars. The presence of quartz, orthoclase and sanidine minerals indicates the presence of acidic materials. This also causes the content of chemical elements in this alluvial deposit to be low, so it is necessary to add organic materials such as municipal waste compost and cow manure which can improve the physical, chemical and biological properties of the soil. The aim of the study was to determine the response of several physical properties of alluvial soil to a combination of municipal waste compost and cow manure after being planted with pakcoy in Alluvial, Indramayu. The objective of this research was to find out relationship between water content and soil bulk density to the harvest of pakcoy after combined with municipal waste compost and cow manure in Alluvial, Indramayu. This study used a randomized block design factorial with two factors. The first factor is municipal waste compost and the second factor is cow manure. Each of them consisted of 4 levels : 0%, 3.0%, 6.0%, and 9.0% with two replication. The results showed that there was no interaction between municipal waste compost with cow manure and municipal waste compost with cow manure had no significant effect on soil water content of pakcoy plants after harvest. Meanwhile, cow manure has an independent effect on soil bulk density in pakcoy plants after harvest. The largest decrease in soil density occurred at a dose of 9.0% (k4), but the addition of cow manure at a dose of 3.0% (k2) was able to reduce the soil bulk density. This K2 treatment was not significantly different from the other treatments. A decrease in soil density to 1.15 g cm-3 (k2) is considered ideal for mineral soils, because in general the bulk density of mineral soils is between 1.1 – 1.6 g cm-3.

Effect of Soluble Silica on the Plant Growth, Leaves Chlorophyll Content and Bulb Quality of the Garlic (Allium sativum L.) against Drought Stress

Background: Garlic is an aromatic spice with nutritional and medicinal values. Climatic variations such as drought, adversely affect Garlic’s morpho-physiological, biochemical attributes and diminish its bulb quality. Soluble silica is a plant-available form of silicon (Si). Silica is beneficial for plant’s healthy growth especially against stress conditions. The present study was aimed to evaluate the effect of soluble silica on the garlic plant growth, leaves chlorophyll content and bulb quality against drought stress. Methods: Garlic was cultivated during the Rabi season (2019-2020) in the experimental field Lohar pipliya (Dewas), India. Randomized experimental blocks consisted of six treatments as follows: T1- Control (well-watered), T2- Drought stress (water supply reduced by about 50%), T3- Drought + a basal dose of NPK fertilizers (BDF) in soil, T4, T5, T6- Drought + BDF + foliar sprays of 7.5, 10 and 12.5 ml L-1 soluble silica respectively. Silica sprays were applied seven-time at a regular interval of 15-days. After 120-days of sowing, plant growth in terms of plants height and number of leaves plant-1 were measured. 120-days leaves chlorophyll, MDA and proline content were estimated. Garlic bulb’s quality in terms of fresh-dry weight and diameter were recorded at the final harvest. Result: Results revealed that drought significantly reduced Garlic’s plant height, bulb quality (weight and diameter), chlorophyll (Chl-a and Chl-b) and increased MDA, proline content in contrast to the well-watered garlic. Fertilizers (BDF) feebly improved garlic bulb quality. However, fertilizers (BDF) supplemented with soluble silica sprays (7.5 ml L-1 less than 12.5 ml L-1 less than 10 ml L-1) significantly increased plant height, bulb weight and diameter, leaves chlorophyll, proline and reduced MDA content over the drought-stressed Garlic. Fertilizers (BDF) supplemented with Soluble silica maintained plant water content, reduced oxidative stress and increased leaves chlorophyll content. These resulted in good quality garlic bulbs in terms of weight and diameter despite the drought stress.

Zero standby power crop water-stress detector leading to the optimization of water usage and yield

Agricultural sensors are powerful tools to optimize crop productivity while conserving natural resources. Here we report a crop water-stress detector based on a plasmonically-enhanced micromechanical photoswitch capable of detecting water content in leaves that is lower than a predetermined threshold without consuming electrical power when the leaf is healthy. The detection mechanism exploits the energy in a specific narrow-spectral band of solar radiation reflected off leaves that is strongly correlated to the water content in plants. This biosensor relies on a spectrally selective infrared plasmonic absorber and a thermally sensitive micro-cantilever to harvest the reflected solar energy and further produce a digitized wakeup-bit only when the monitored leaf is water-stressed. In particular, we demonstrate that the detector activates a commercial water pump when a soybean plant is water-stressed. The 10-year battery lifetime of the proposed detector pave the way for the development of high-granularity, maintenance-free sensor networks for large-scale smart-farms.

Smart Plant Monitoring System with NodeMCU8266 using IOT

Plants play a vital role in maintaining the ecological cycle, and thus, to maintain the plant's proper growth and health, adequate monitoring is required. Hence, the aim of the chapter is to create a smart plant monitoring system using automation and internet of things (IOT) technology. This topic highlights various features such as smart decision making based on soil moisture real-time data. For this purpose, sensors like soil moisture sensor, DHT11 sensor, level sensor, etc. are used. The soil moisture sensor measures the level of moisture (i.e., water content of different plants). The signal will be sent to Arduino board when the moisture level drops below the marginal value, which triggers the pumping of water into the plant by the pump. When the moisture level reaches absolute value, the pump is halted. The other condition for this process is level sensor. Level sensor senses the water level in the tank and sends the information of water level value to Arduino board and Arduino board to cloud. The whole data about the plant monitoring will be sent to the cloud server.

The Critical Role of Arbuscular Mycorrhizal Fungi to Improve Drought Tolerance and Nitrogen Use Efficiency in Crops.

Drought stress (DS) is a serious abiotic stress and a major concern across the globe as its intensity is continuously climbing. Therefore, it is direly needed to develop new management strategies to mitigate the adverse effects of DS to ensure better crop productivity and food security. The use of arbuscular mycorrhizal fungi (AMF) has emerged as an important approach in recent years to improve crop productivity under DS conditions. AMF establishes a relationship with 80% of land plants and it induces pronounced impacts on plant growth and provides protection to plants from abiotic stress. Drought stress significantly reduces plant growth and development by inducing oxidative stress, disturbing membrane integrity, plant water relations, nutrient uptake, photosynthetic activity, photosynthetic apparatus, and anti-oxidant activities. However, AMF can significantly improve the plant tolerance against DS. AMF maintains membrane integrity, improves plant water contents, nutrient and water uptake, and water use efficiency (WUE) therefore, improve the plant growth under DS. Moreover, AMF also protects the photosynthetic apparatus from drought-induced oxidative stress and improves photosynthetic efficiency, osmolytes, phenols and hormone accumulation, and reduces the accumulation of reactive oxygen species (ROS) by increasing anti-oxidant activities and gene expression which provide the tolerance to plants against DS. Therefore, it is imperative to understand the role of AMF in plants grown under DS. This review presented the different functions of AMF in different responses of plants under DS. We have provided a detailed picture of the different mechanisms mediated by AMF to induce drought tolerance in plants. Moreover, we also identified the potential research gaps that must be fulfilled for a promising future for AMF. Lastly, nitrogen (N) is an important nutrient needed for plant growth and development, however, the efficiency of applied N fertilizers is quite low. Therefore, we also present the information on how AMF improves N uptake and nitrogen use efficiency (NUE) in plants.

Brassinosteroid application increases tomato tolerance to salinity by changing the effects of stress on membrane integrity and gas exchange

Salinity is one of the environmental stresses that most cause losses in agricultural systems, including tomato production. Brassinosteroids, such as epibrassinolide (EBL), have multiple actions in essential processes in plants. Thus, the objective of this study was to evaluate the contributions of EBL to the growth, physiology, and production of tomato plants under salinity. The experiment was conducted in a factorial scheme, with five levels of water salinity (0.5 [the control], 1.5, 3.0, 4.5, and 6.0 dS m-1) and two concentrations of EBL (0 and 10-6 M). Salt stress reduced tomato growth, relative water content, membrane integrity, gas exchange, and fruit production. However, the exogenous application of EBL attenuated the adverse effects, partially improving these characteristics at all salinity levels. EBL reduced electrolyte leakage and increased membrane integrity and relative water content in control and stressed plants. Additionally, it increased the content of photosynthetic pigments, stomatal conductance, transpiration, and photosynthesis, which led to higher leaf dry mass production, fruit transverse diameter, and production per plant. Therefore, our results confirmed that foliar application of EBL improved the characteristics of stressed and non-stressed tomato plants.