Effect of drought stress and mycorrhizal dose on growth and yield of maize (Zea mays L.)

This study aims to determine the effect of drought stress and mycorrhizal dose on the growth and yield of maize (Zea mays L.). The research was done in the BPTP Banten Screen House and the Soil and Climate Laboratory of the Faculty of Agriculture, Sultan Ageng Tirtayasa University starts from November 2020 until February 2021. This study used a factorial randomized block design (RBD) consisting of two factors. First factor was drought stress with four levels, namely k1 (100% FC), k2 (80% FC), k3 (60% FC), and k4 (40% FC) and second was the mycorrhizal dose with 3 levels, called m0 (0 g/pot), m1 (10 g/pot), and m2 (20 g/pot). There were 12 treatment combinations that were repeated 3 times in order to obtain 36 experimental units. The results showed that the drought stress treatment had a significant effect on maize plant height at 7 WAP of 174.22 cm, plant dry weight of 86.67 g, root dry weight of 21.67 g, and seed dry weight of 37 g. Drought stress of 40% FC can reduce the growth and yield of maize. The mycorrhizal dose treatment had no significant effect on the growth and yield of maize. The application of mycorrhizal dose of 20 g/pot tends to increase the growth and yield of maize. There was no interaction between drought stress treatment and mycorrhizal dose on growth and yield of maize.

Shade stress on maize seedlings biomass production and photosynthetic traits

ABSTRACT: The responses of two maize (Zea mays L.) cultivars, ‘LY336’ (shade tolerant) and ‘LC803’ (shade sensitive), to shade stress in a pot experiment conducted in the 2015 and 2016 growing seasons were investigated. The impact of 50% shade stress treatment on shoot biomass, photosynthetic parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content was evaluated. The shoot biomass of the two maize hybrids was decreased significantly by shade stress treatment, for shade stress 7 d, the LC803 and LY336 were reduced by 56.7% and 44.4% compared with natural light. Chlorophyll fluorescence parameters of LY336 were not significantly affected by shade stress, whereas those of LC803 were significantly affected, the Fo increased under shade stress; however Fm, FV/FM and ΦPSII were decreased under shade stress. Among photosynthetic parameters measured, net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate were significantly decreased compared with natural light, LY336 and LC803 reduction by 28.0%, 22.2%, 57.7% and 35.5%, 18.9%, 62.4%; however, intercellular CO2 concentration (Ci) was significantly increased, for the two cultivars. Under shade stress for different durations (1, 3, 5, 7 d), Pn, Gs, Ci, and MDA content differed significantly between the two cultivars. Results indicated that different maize genotypes showed different responses to shading. Shade-tolerant genotypes are only weakly affected by shade stress.

Determination of carbohydrate accumulation and plant growth dynamics in snowdrop (Galanthus elwesii Hook.) response to moisture levels in different substrates

In terms of botany, geophytes are known by their own survival strategy due to have a swollen storage organs. Snowdrops (Galanthus, 20 spp.; Amaryllidaceae) are important type of wild-sourced ornamental bulb genus in all geophyte species. Also, have a great deal of potential for use on landscape designs. Whereas, not much study has been done regarding the growth dynamics of snowdrops at harsh environmental conditions. This experiment was conducted to evaluate the effects of abiotic stress conditions on the performance of snowdrop (Galanthus elwesii Hook.) in soiless culture. Substrates and moisture were the variables. Peat + perlite and cocopeat were used as a substrate in pots. Moisture levels were applied; ML1, ML2 (well-watered and moderately tolerant treatments), ML3 (moderate stress) and ML4 (severe stress). Moisture had a statistically significant effect (P < 0.05) on circumference size, height and weight of the snowdrop bulbs. Plant height and carbohydrate accumulation were also affected by moisture levels in different substrates. The correlation between total carbohydrate (r = 0.95) and starch (r = 0.98) were positively determined. The reduced sugar, total sugar, starch and total carbohydrate values were increased by the severe stress treatment (ML4).

Molecular Manipulation of the MiR396/GRF Expression Module Alters the Salt Stress Response of Arabidopsis thaliana

We previously demonstrated that microRNA396 (miR396) abundance is altered in 15-day-old Arabidopsis thaliana (Arabidopsis) whole seedlings following their exposure to a 7-day salt stress treatment regime. We, therefore, used a molecular modification approach to generate two new Arabidopsis transformant populations with reduced (MIM396 plants) and elevated (MIR396 plants) miR396 abundance. The exposure of 8-day-old wild-type Arabidopsis whole seedlings and a representative plant line of the MIM396 and MIR396 transformant populations to a 7-day salt stress treatment regime revealed unique phenotypic and physiological responses to the imposed stress by unmodified wild-type Arabidopsis plants and the MIM396 and MIR396 transformat lines. A quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) approach was, therefore, applied to demonstrate that the plant line specific responses to salt stress likely stemmed from the unique molecular profile of each of the GROWTH REGULATING FACTOR (GRF) transcription factor gene family members which form posttranscriptional targets of miR396-directed expression regulation. RT-qPCR additionally revealed that, in 15-day-old Arabidopsis whole seedlings, the three previously identified putative target genes of miR396 belonging to the NEUTRAL/ALKALINE NONLYSOSOMAL CERAMIDASE-LIKE (NCER) gene family, including NCER1, NCER2, and NCER3, do not form targets of miR396-directed expression regulation at the posttranscriptional level. Taken together, the phenotypic and molecular analyses presented here demonstrate that alteration of the miR396/GRF expression module is central to the molecular response of Arabidopsis to salt stress.

Chlorophyll and Carotenoid Level Comparisons of Pigeon Orchid (Dendrobium crumenatum) in Water and Light Stress Treatment

Environtmental conditions in which plants grow are always changing which when exceeding the tolerance limit will result in stress. Water and light stress affect the pigment content of photosynthesis such as chlorophyll and carotenoids. <em>Dendrobium crumenatum </em>is one of orchid species that is judged to be resistant to various types of environtmental conditions, so it can grow well in any environtment. This research aims to determine the comparison of chlorophyll and carotenoid levels of <em>D. crumenatum </em>from Bantul lowland population, Special Region of Yogyakarta which is given water and light stress treatment. The methods used are extraction with alcohol solvent (96%) and absorbtion level measurements with spectrophotometry at wavelengths 470, 645, and 663 nm. The highest chlorophyll a level contained in the leaves of <em>D. crumenatum </em>which is given water stress treatment, highest chlorophyll b level in control plant, highest total chlorophyll in the leaves which is given water stress treatment, and highest carotenoid level found in the leaves which is given light stress treatment.

Metabolomics Response to Drought Stress in Morus alba L. Variety Yu-711

Mulberry is an economically significant crop for the sericulture industry worldwide. Stresses such as drought exposure have a significant influence on plant survival. Because metabolome directly reflects plant physiological condition, performing a global metabolomic analysis is one technique to examine this influence. Using a liquid chromatography-mass spectrometry (LC-MS) technique based on an untargeted metabolomic approach, the effect of drought stress on mulberry Yu-711 metabolic balance was examined. For this objective, Yu-711 leaves were subjected to two weeks of drought stress treatment and control without drought stress. Numerous differentially accumulated metabolic components in response to drought stress treatment were revealed by multivariate and univariate statistical analysis. Drought stress treatment (EG) revealed a more differentiated metabolite response than the control (CK). We found that the levels of total lipids, galactolipids, and phospholipids (PC, PA, PE) were significantly altered, producing 48% of the total differentially expressed metabolites. Fatty acyls components were the most abundant lipids expressed and decreased considerably by 73.6%. On the other hand, the prenol lipids class of lipids increased in drought leaves. Other classes of metabolites, including polyphenols (flavonoids and cinnamic acid), organic acid (amino acids), carbohydrates, benzenoids, and organoheterocyclic, had a dynamic trend in response to the drought stress. However, their levels under drought stress decreased significantly compared to the control. These findings give an overview for the understanding of global plant metabolic changes in defense mechanisms by revealing the mulberry plant metabolic profile through differentially accumulated compounds.