Plant Growth Quality Research Articles

Exploring the physiological and agronomic response of Armoracia rusticana grown in rainfed Mediterranean conditions

Horseradish (Armoracia rusticana) is a perennial plant, belonging to the Brassicaceae family, whose roots are widely used as a cooking spice and flavouring agent across the world and has recently acquired considerable scientific interest due to the richness of phytochemicals. Aim of the study was to explore water relations in plants grown in pots and subject to severe stress conditions and gas exchange, plant growth, and agronomic characteristics of two horseradish accessions grown in open field under rainfed Mediterranean conditions. Total and osmotic leaf water potential were significantly reduced by water stress to a similar extent at predawn and middle day. The carbon isotope composition (δ13C) (on average –34.2 and –28.9‰ in leaves and roots, respectively) resulted statistically different among water stress treatments in leaves collected at middle day. In open field, during the vegetative development, plants regulate the foliage expansion depending on rainfall distribution and temperature. When the dry period occurs, plants get rid of several mature leaves that dry completely, and might develop new leaves in the next period, when the air-cools and rainfall increases. During the dry period, horseradish optimised gas exchange during the day by increasing the net CO2 assimilation rate during the early morning (up to 31 μmol CO2 m–2s–1, on average), when the sunlight intensity and the air temperature conditions are more favourable. The species, which rely on an annual rainfall of about 680 mm, produced about 11.5 and 24.3 t/ha of roots from one- and two-year-old plantations, respectively. Regardless of accessions, close relationships were found between the number of leaves and root weight (R2=0.88 and P≤0.01) and diameter (R2=0.82 and P≤0.01). The results advise the importance to know the physiology and agronomic characteristics of horseradish to purposefully apply agronomic practices and strategies to maximise benefits for production and root quality.

Yellow light promotes the growth and accumulation of bioactive flavonoids in Epimedium pseudowushanense

The plant species of the genus Epimedium L. are well-known traditional Chinese medicinal herbs with special therapeutic effects on human beings and animals in invigorating sexuality and strengthening muscles and bones. In large-scale cultivating Epimedium that is a typical shade plant species, they are arbitrarily covered with black colored shade nets. However, their optimal growth conditions, especially light, are still less understood. During the investigation of different light qualities on the growth of Epimedium pseudowushanense, it was found that, all the values of plant growth characteristics (except shoot number) and photosynthetic characteristics were lower under red, yellow, or blue light treatment than under white light treatment. However, yellow light treatment had beneficial effects on shoot number, dry biomass (per plant) as well as net photosynthesis rate (Pn) and maximal apparent quantum efficiency (AQY) in E. pseudowushanense when compared with red or blue light treatment. More importantly, we found that E. pseudowushanense accumulated higher levels of bioactive flavonoids under yellow light treatment than under white, red, or blue light treatment. Furthermore, both RNAseq and qPCR analyses revealed that yellow light could highly up-regulate the expression levels of flavonoid biosynthetic genes, in particular CHS1, F3H1, PT_5, and raGT_5 that possibly contributed to the enhanced accumulation of bioactive flavonoids in E. pseudowushanense. Taken together, our study revealed that yellow light is the optimal light for the growth of E. pseudowushanense. Our results provided key information on how to improve the cultivation condition and concurrently enhance the accumulation of bioactive flavonoids in E. pseudowushanense.

Effects of Arbuscular Mycorrhiza Fungi on the Growth Characteristics, Root Morphology, and Ion Distribution of Pyrus betulaefolia Bunge under Saline-Alkaline Stress

Abstract In this study, Pyrus betulaefolia Bunge seedlings were used to investigate the effects of an arbuscular mycorrhiza fungus (AMF; Funneliformis mosseae) on plant-growth characteristics, root morphology, salt tolerance, and ion distribution under saline-alkaline stress. An indoor pot experiment was conducted in which seedlings were inoculated with Funneliformis mosseae under treatments of four different concentrations of Na2CO3 solution. The results show that AMF could establish symbiotic relations with the P. betulaefolia root system under Na2CO3 stress. Under the same Na2CO3 stress, AMF significantly increased the height growth and biomass accumulation of P. betulaefolia seedlings. AMF also promoted the root growth of P. betulaefolia seedlings. AMF inoculation significantly affected the absorption and distribution of K+ and Na+ in P. betulaefolia. The K/Na ratios in the roots and leaves of seedlings inoculated with AMF were higher than those of seedlings without inoculation. The results of this study show that inoculation with AMF had a positive effect on enhancing the saline-alkaline tolerance of P. betulaefolia, and root treatment of P. betulaefolia seedlings with Funneliformis mosseae has the potential for application in the development of saline-alkaline soil vegetation.

Development of Multifunctional Film for Greenhouse Applications in Tropical Regions

Single-purpose greenhouse films such as UV-blocking, NIR-blocking, or ultrathermic films are commonly developed in various climate regions. However, multifunctional films of combined functions are rarely explored, especially in the tropical regions. In this research, a multifunctional film having high UV filtration, high NIR reflection, and good light diffusion was developed for a greenhouse cover application in tropical regions. Effects of type, quantity, and particle size of additives on optical properties (280–2500 nm) and mechanical properties of 3-layer laminated films comprising 90% LLDPE/10% EVA polymer matrix and additives were studied. Results show that properties of those films are adjustable by varying types, particle size, and content of additives. The UV transmission of the film was ranged from 13.7 to 32.7 %T, NIR reflection from 12.1 to 19.8 %R, and %haze diffusion from 39.5 to 72.3 where photosynthetically active radiation (PAR) transmission was in the range of 62.6–78.9 %T. Those films exhibit tensile strength of 18–24 MPa, modulus of elasticity of 200–280 MPa, and elongation at break of 610–810%. A field test of the newly developed films as a cover for a greenhouse of 6 m wide ×24 m long ×4.3 m high with double roof design showed a better quality of plant growth in terms of weight, height, and bush width compared to a 7% UV absorber commercial film.

A method for determining vegetation growth process using remote sensing data: A case study in the Three-River Headwaters Region, China

Accurate measurements of the associated vegetation phenological dynamics are crucial for understanding the relationship between climate change and terrestrial ecosystems. However, at present, most vegetation phenological calculations are based on a single algorithm or method. Because of the spatial, temporal, and ecological complexity of the vegetation growth processes, a single algorithm or method for monitoring all these processes has been indicated to be elusive. Therefore, in this study, from the perspective of plant growth characteristics, we established a method to remotely determine the start of the growth season (SOG) and the end of the growth season (EOG), in which the maximum relative change rate of the normalized difference vegetation index (NDVI) corresponds to the SOG, and the next minimum absolute change rate of the NDVI corresponds to the EOG. Taking the Three-River Headwaters Region in 2000–2013 as an example, we ascertained the spatiotemporal and vertical characteristics of its vegetation phenological changes. Then, in contrast to the actual air temperature data, observed data and other related studies, we found that the SOG and EOG calculated by the proposed method is closer to the time corresponding to the air temperature, and the trends of the SOG and EOG calculated by the proposed method are in good agreement with other relevant studies. Meantime, the error of the SOG between the calculated and observed in this study is smaller than that in other studies.

Effects of Different PGPR Formulations, Chemical Fertilizers and Their Combinations on Some Plant Growth Characteristics of Poinsettia

This study was carried out to determine effects of different PGPR formulations, chemical fertilizers and their combinations on some plant growth characteristics of poinsettia under climate-controlled research greenhouse between July 2015 and July 2017. In the study, rooted cuttings of poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch cv. Christmas Feelings) were used as plant material. The applications were created as formulation 1, formulation 2, formulation 3, formulation 4, the full amount of commonly used chemical fertilizer (100% CF), by combining the reduced amount of chemical fertilizer by 50% with each bacterial formulation and control. Plant height, main stem diameter, number of bract, length and diameter of root, fresh and dry weight of plant were evaluated in the experiment. According to CF and control applications, BIV+CF application was increased in the number of bract leaves between 14.76% and 29.32%; and it was also increased in plant height between 2.87% and 5.27%, respectively. The highest plant fresh weight (16.93 g) was obtained from BII and CF applications. The highest average fresh (4.69 g) and dry (1.57 g) plant weight were determined in BII application. It has been determined that bacterial formulations BIV+CF, BIII+CF, BIV and BII, which have positive effects on some plant growth and quality characteristics of poinsettia, can be used in poinsettia production stage. Thus, bacterial formulations may allow reducing the using chemical fertilizer in its cultivation.

The role of selenium on mitigating arsenic accumulation, enhancing growth and antioxidant responses in metallicolous and non-metallicolous population of Isatis cappadocica Desv. and Brassica oleracea L.

A hydroponic experiment was conducted to explore the interactive effects of selenium (Se) supplementation (0, 5, and 10 μM) and arsenic (As) toxicity (0, 200, and 400 μM) on the growth, accumulation, and oxidative damage along with defense mechanisms of metallicolous (MP) and non-metallicolous population (NMP) of Isatis cappadocica, an As-hyperaccumulator, and Brassica oleracea as reference brassica. The results revealed that As stress significantly hampered plant growth particularly in B. oleracea. It reduced plant growth due to enhanced oxidative load of As-stressed plants. Between the two Isatis populations, metallicolous plants accumulated significantly higher As, however with considerably low growth defects. Furthermore, Se supplementation counteracted the adverse effects of stress on growth and physiological performance of all studied plants. Addition of Se, particularly at higher dose (10 μM), significantly suppressed root As uptake and slightly its accumulation in shoots of B. oleracea plants treated with 400 μM As, and thus improved growth characteristics of stressed plants. Under As stress, Se supplementation increased the activities of enzymatic (peroxidase (POD) and glutathione reductase (GR)) and non-enzymatic (anthocyanins and total flavonoids) antioxidants, thereby suggesting relieved As stress by reduced oxidative damage. Taken together, these results support the beneficial role of Se in the regulation of As stress by improving growth, physiology, and antioxidant capacity, and highlight its significance for plants grown on such metal-contaminated soils.

Potential roles of melatonin and sulfur in alleviation of lanthanum toxicity in tomato seedlings

Owing to the active use of rare-earth elements in many areas, it is necessary to study their behavior in the environment and their biological impact on plants. Despite the role of melatonin and sulfur in plant growth, development and abiotic stress tolerance; it is still not clear how they have a strong regulatory influence and synergistic effect on growth, physiological and biochemical characteristics of plants under different environmental stresses. Therefore, this study highlights how melatonin and sulfur together potentially involved in a reversal of lanthanum-inhibited photosynthetic and growth responses in tomato seedlings. Here, we reported that seedlings grown in a medium containing 150 μM lanthanum exhibited increased overproduction of reactive oxygen species (ROS) and lipid peroxidation together with increased Chlorophyll degradation, and activity of chlorophyllase, proline dehydrogenase and glycolate oxidase (GOx), and decreased photosynthesis and growth. However, the application of melatonin and sulfur showed significant responses on tomato seedlings, although the response of their combined treatment was more effective by further increasing photosynthesis and growth under lanthanum toxicity. Melatonin supplied with sulfur suppressed ROS formation, lipid peroxidation and activity of GOx, and increased photosynthesis by upregulating activities of carbonic anhydrase and ribulose-1,5-bisphosphate carboxylase/oxygenase. Also, sulfur supplementation with melatonin to seedlings resulted in an elevation in the accumulation of Chl and proline by increasing δ-aminolevulinic acid and activity of δ-aminolevulinic acid dehydratase and Δ1-pyrroline-5-carboxylate synthetase activity. The administration of melatonin with sulfur substantially induced upregulation of enzymes (superoxide dismutase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase) activities involved in the antioxidant system, thereby mitigating ROS-induced oxidative damage. Thus, this study provides strong evidence that melatonin and sulfur have strong regulatory influence and synergistic role in alleviating the adverse effect of lanthanum-toxicity by increasing photosynthesis and growth.

Morphological and physiological response of Acer catalpifolium Rehd. Seedlings to water and light stresses

As a critically endangered species, Acer catalpifolium Rehd. is included in the wild plants with extremely small populations (WPESP) rescue and protection plan. Understanding of the responses of A. catalpifolium to various resource and environment conditions could help identify potentially suitable environments for its conservation. We used an orthogonal experiment design to evaluate the growth, morphological and physiological responses of A. catalpifolium and a widespread same-genus species A. mono to diverse water and light stresses. The results showed that a 75% soil water holding capacity and moderate shade are suitable for seedling growth. Drought and shade had significant negative effects on plant growth, biomass accumulation, and physiological functions. Lowering specific leaf areas (SLA), increasing root biomass allocation, and pigment content were the main strategies for enhancing water and light capturing abilities to acclimate to the limited ambient resources. The general plasticity index of plant growth, biomass, and physiological characteristics were higher in A. mono than in A. catalpifolium. We also explored the suitable light and water requirements for A. catalpifolium seedling growth. Our research would be useful for population regeneration and could aid in biodiversity conservation of Acer species.

Development of a structural growth curve model that considers the causal effect of initial phenotypes

BackgroundGrowth curves have been widely used in genetic analyses to gain insights into the growth characteristics of both animals and plants. However, several questions remain unanswered, including how the initial phenotypes affect growth and what is the duration of any such impact. For beef cattle production in Japan, calves are procured from farms that specialize in reproduction and then moved to other farms where they are fattened to achieve their market/purchase value. However, the causal effect of growth, while calves are on the reproductive farms, on their growth during fattening remains unclear. To investigate this, we developed a model that combines a structural equation with a growth curve model. The causal effect was modeled with B-splines, which allows inference of the effect as a curve. We fitted the proposed structural growth curve model to repeated measures of body weight from a Japanese beef cattle population (n = 3831) to estimate the curve of the causal effect of the calves’ initial weight on their trajectory of growth when they are on fattening farms.ResultsMaternal and reproduction farm effects explained 26% of the phenotypic variance of initial weight at fattening farms. The structural growth curve model was fitted to remove the effects of these factors in growth curve analysis at fattening farms. The estimated curve of causal effects remained at approximately 0.8 for 200 d after the calves entered the fattening farms, which means that 64% of the phenotypic variance was explained by the initial weight. Then, the effect decreased linearly and disappeared approximately 620 d after entering the fattening farms, which corresponded to an average age of 871.5 d.ConclusionsThe proposed model is expected to provide more accurate estimates of genetic values for growth patterns because the confounding causal factors such as maternal and reproduction farm effects are removed. Moreover, examination of the inferred curve of the causal effect enabled us to estimate the effect of a calf’s initial weight at arbitrary times during growth, which could provide suitable information for decision-making when shifting the time of slaughter, building models for genetic evaluation, and selecting calves for market.

Growth-promoting bioactivities of Bipolaris sp. CSL-1 isolated from Cannabis sativa suggest a distinctive role in modifying host plant phenotypic plasticity and functions

Endophytic fungi have been considered as strong plant growth promoters due to phytohormones production. The current study reports the isolation of endophytic fungi from bio-prospective medicinal plant cannabis sativa. Endophytic fungus Bipolaris sp. CSL-1 from the leaves of C. sativa was isolated. Culture filtrate (CF) was primarily investigated for indole-3-acetic acid (IAA) and gibberellins (GAs) and was further evaluated for its capability to enhance mutant Waito-C rice growth attributes. A variety of plant growth characteristics, including seedling length, seedling biomass, and chlorophyll content, were significantly promoted by the CF, and the growth-promoting effect was due to IAA and various GAs in the CF. Gas chromatography/mass spectrometry analysis revealed the quantities (ng/mL) of various GAs, including GA1 (0.758 ± 0.005), GA3 (0.00015 ± 0.005), GA4 (0.945 ± 0.081), GA7 (0.6382 ± 0.012), GA9 (0.0125 ± 0.0002), and GA24 (0.0139 ± 0.0013). Similarly, endogenous GA4 (33.243 ± 4.36), GA24 (29.64 ± 2.68), GA7 (22.5 ± 1.3), and GA12 (25.21 ± 2.8) were significantly upregulated in rice mutant after CF application. Furthermore, RT-PCR indicated that IAA and GA pathway genes (des, ggs2, P50-1, P450-4, and iaaH) were expressed in CSL-1 and the combined application of CSL-1 spore suspension with yucasin and uniconazole to maize seedlings revealed that CSL-1 such as exogenous GA3 and IAA alleviated the negative effect of uniconazole and yucasin and promoted maize-seedling growth. These findings suggest that the endophytic fungus CSL-1, which produces IAA and GAs, can play a vital role in promoting plant growth and that CSL-1 could be used to enhance crop growth and mitigate plant stress under a variety of environmental conditions.

The influence of light spectrum on morphogenesis of orchid germs in vitro

The aim of the study is to reveal growth and developments specificities of orchid (Cymbidium hybridum F1) germinant in vitro cultured early in the ontogenesis in relation to various light spectra. Chromatic and achromatic luminous tubes (Philips, TLD 18 W) were used as lighting sources. 4 light patterns were tested: control group – colorless (white) light WL; group 1 – WL with addition of red WL+RL, group 2 – WL and blue WL+BL, group 3 – WL and green WL+GL. The authors showed that during C. hybridum F1cultivation in type breeding ground, morphometric growth indexes of root and leaf and wet weight of germs raised with the increase of red light part in PAR (photosynthetically active radiation) flux, thought stem length was twice bigger under the mix of colorless and green light, and also blue light addition to achromatic emission aided the reduction of germ parameters, in contrast with control group. Growth characteristics of plants, cultivated under photoculture conditions, can be adjusted by light with varied spectral content.

Prohexadione-Calcium Application during Vegetative Growth Affects Growth of Mother Plants, Runners, and Runner Plants of Maehyang Strawberry

Strawberry (Fragaria × ananassa Duch.) is an important horticultural crop that is vegetatively propagated using runner plants. To achieve massive production of runner plants, it is important to transfer the assimilation products of the mother plant to the runner plants, and not to the runner itself. Application of prohexadione–calcium (Pro–Ca), a plant growth retardant with few side effects, to strawberry is effective in inhibiting transport of assimilates to runners. This study aimed to determine the optimum application method and concentration of Pro–Ca on the growth characteristics of mother plants, runners, and runner plants for the propagation of strawberry in nurseries. Pro–Ca was applied at the rate of 0, 50, 100, 150, or 200 mg·L−1 (35 mL per plant) to plants via foliar spray or drenching under greenhouse conditions at 30 days after transplantation. Petiole lengths of mother plants were measured 15 weeks after treatment; growth was suppressed at the higher concentrations of Pro–Ca regardless of the application method. However, the crown diameter was not significantly affected by the application method or Pro–Ca concentration. The number of runners was 7.0 to 8.2, with no significant difference across treatments. Runner length was shorter at higher concentrations of Pro–Ca, especially in the 200 mg·L−1 drench treatment. However, fresh weight (FW) and dry weights (DW) of runners in the 50 mg·L−1 Pro–Ca drench treatments were higher than controls. Foliar spray and drench treatments were more effective for runner plant production than the control; a greater number of runner plants were produced with the 100 and 150 mg·L−1 Pro–Ca foliar spray treatment and the 50 and 100 mg·L−1 drench treatment. The FW and DW of the first runner plant was not significantly different in all treatments, but DW of the second runner plant, and FW and DW of the third runner plant were greatest in the 50 mg·L−1 Pro–Ca drench treatment. These results suggested that growth and production of runner plants of Maehyang strawberry were greatest under the 50 mg·L−1 Pro–Ca drench treatment.

Assessment of GA3 and BA application on gerbera cultivation in soilless culture

This research was carried out to determine the effect of gibberellic acid (GA3) and benzyladenine (BA) application on yield and quality components (multiplication ratio, flower stem length, flower diameter, vase life, flower stem diameter,) of gerbera. Three different levels of GA3 (125, 250, 500 ppm) and BA (100, 200, 400 ppm) were applied by foliar spray. Compared to BA application, GA3 applications gave good results on yield and quality parameters. The maximum yield was obtained by 125 ppm of GA3 application. It was found that 500 ppm of GA3 application most effective on stem length and flower diameter. On the other hand, it's determined that 400 ppm BA application significantly increased stem diameter and multiplication ratio. Its concluded that, the GA3 and BA demonstration interference in growth characteristics of gerbera plant.

EFFECT OF MYCORRHIZAE AND DIFFERENT RATES OF NPK ON VEGETATIVE GROWTH AND YIELD OF TOMATO PLANT UNDER NORTH SINAI CONDITIONS

The experiments were conducted to evaluate the effect of mycorrhizae (Glomus sp. and Gigspora sp.) application on the vegetative growth and yield of tomato plants (Alisa cultivar), and its relevance to the mineral fertilizers requirements as NPK during the seasons of 2015/2016 and 2016/2017. The experiments were conducted at Baloza Research Station, Desert Research Center, North Sinai Governorate, Egypt. The experimental design was a randomized complete block design with three replicates, every replicate included 4 treatments (75 and100% of the recommended mineral fertilizer only or combined with the mycorrhizae treatment). The results showed that mycorrhizae application significantly increased the vegetative growth characters of tomato plant such as plant height, number of shoots, number of leaves, stem diameter, fresh and dry weights and yield. There were no significant differences in the vegetative growth characteristics of tomato plants receiving 75% of mineral fertilizers in addition to mycorrhizae application as compared with plants receiving 100% of mineral fertilizers only, except for the fresh weight of plants. The plants were received 100% of the recommended mineral fertilizers combined with mycorrhizae treatment gave the highest values of vegetative growth characters and yield. Therefore, we recommended that, using of mycorrhizae could be affective to maximize the utilization of mineral fertilizers, in addition, the mycorrhizea is ecofriendly, economically and consid ered as one of the most important bio-fertilizer resources.

2018–2019 Citrus Production Guide: Plant Growth Regulators

Plant growth regulators (PGRs) are a tool used to manipulate vegetative and reproductive growth, flowering, and fruit growth and development. PGRs have been successfully used in agriculture for decades to amend plant growth characteristics to maximize yield and grower profit. This 4-page fact sheet is part of the 2018–2019 Citrus Production Guide. Written by Tripti Vashisth, W. Chris Oswalt, Mongi Zekri, Fernando M. Alferez, and Jamie D. Burrow, and published by the Horticultural Sciences Department, January 2019. CMG17/HS1310: 2022–2023 Florida Citrus Production Guide: Plant Growth Regulators (ufl.edu)

Effects of the ephemeral stream on plant species diversity and distribution in an alluvial fan of arid desert region: An application of a low altitude UAV.

Biodiversity conservation, plant growth and spatial distribution of plant species are the central issues in contemporary community ecology. Ephemeral stream may influence soil properties, which in turn may determine biodiversity and function of an ecosystem in alluvial fan of arid desert region. Ephemeral stream is one of the most common natural disturbances, yet the effects of the ephemeral stream on plant communities in terms of species diversity and plant species distribution remain poorly studied. In this study, the information of species distribution, ephemeral stream beds (‘washes’), and the characteristics of plant growth, i.e. height, crown area, were interpreted at different heights using the images of low altitude unmanned aerial vehicle (UAV). After that, soil properties such as soil texture (sand, silt and clay), soil water content, pH, soil organic matter, soil electric conductivity, soil bulk density and the percentage of gravel content, and their relationships with UAV data were assessed in order to explore the influences of ephemeral stream on species diversity, plant growth characteristics and species distribution in an alluvial fan of arid desert region. The results showed that deep-rooted plants were only distributed in washes whereas shallow-rooted plants were distributed in both washes and the outside of washes (‘non-washes’). Species richness was significantly higher in washes than that in non-washes whereas the opposite pattern was true for abundance. Soil properties, plant height and crown area were higher in washes than that in non-washes. Plant height, crown area and the total number of individual plants increased with increasing wash width and per unit length of stream flow. This study highlights that the coupling factors of ephemeral stream, such as soil erosion, particle transport and sedimentation, can dramatically cause changes in soil properties and total number of individual plants, and hence, can influence species diversity, plant growth characteristics and spatial distribution of plant species in an alluvial fan of arid desert regions.

A scale-invariant lettuce leaf area calculation using machine vision and knowledge-based methods

Leaf area is one of the most significant reference tools to characterize plant growth and predict growth stages. Scale invariance in calculating leaf area needs to be understood in the lettuce growth monitoring context. Using machine vision and knowledge-based classifiers, this research produced a system for a scale invariant area calculation of lettuce leaf area by detecting a template marker with a known area for scaling area measurements. Results showed that knowledge-based algorithm can improve the performance of the machine vision classifiers for rejecting false positives even for a limited number of training datasets. Area measurements produced by the system performed well in terms of root-mean-square error (RMSE). Â

Effects of mulching and zinc on physiological responses and yield of sweet pepper (Capsicum annuum) under high altitude cold desert condition

In arid regions of the world, drought stress, lack of water availability and micro nutrient deficient sandy soils affect normal growth and development of plants resulted in poor growth and yield. The aim of the study was to evaluate combined effects of mulching and zinc application on growth, physiological responses and yield of capsicum (Capsicum annuum L.) under high altitude cold desert conditions. Field experiment was conducted in the cold desert environment of trans-Himalayan Ladakh region with five levels of zinc (ZnSO4), viz. 0, 10, 20, 30 and 40 kg ha-1 with and without polythene mulching during 2013 and 2014 cropping season. Results showed that mulching with zinc significantly improved leaves membrane stability index (MSI) and relative water content (RWC) and also helped in reducing leaf water loss (LWL) and electrolyte leakage (EL) indicating better plant physiological responses. Significant improvement in leaf chlorophyll content was also observed. Both mulching and zinc application remarkably enhanced plant growth characters and capsicum yield. But, during 2014, sudden decrease in minimum and maximum temperature at flowering and fruiting stage adversely affected proper fruit set and its development resulting into poor capsicum yield. Application of mulch also reduced irrigation water requirement of plants. Knowledge from the present study indicated that combined application of ZnSO4 and mulching could be the feasible strategy against weather abnormality, water savings and obtaining better yield of vegetables grown in zinc deficient sandy soils of arid regions.

Pengaruh Pupuk Organik Gulma Siam (Chromolaena odorata L.) dan Ampas Bungkil Mimba (Azadiracta indica A.Juss) pada Sifat Kimia Tanah dan Performa Tanaman Padi Hitam

A black rice cultivation study was conducted at Kampung Cinenggang, Cileles Villages, Jatinangor. This research analyzed the effect of organic fertilizer such as siam weed compost and neem cake waste to black rice growth and soil chemicals. The experiment was arranged in randomized block design consisted of five treatments and six replications as follow : neem cake waste , siam weed compost, cow manure, urea were used as the N sources by comparing with no application (control). Overall the result of the study showed that there were no significant differences among treatment in plant growth characters such as plant height and SPAD, except control. In tiller number, the effect of neem cake waste and siam weed compost were significant different if compared with other treatments. Furthermore, the effect of neem cake waste gives a positive effects to soil chemicals which in turn enhanced the growth of black rice. it is recommended that organic fertilizers (neem cake waste and siam weed compost) be utilized instead of chemical fertilizer. Keywords: black rice , neem cake waste, organic fertilizer, siam weed compost, plant growth, soil chemicals