Ana I Vargas

• Researcher at University of Florida

Soil salinity poses a global threat to crop production. Early understanding of plant physiological responses to salinity stress can be critical to implementing timely stress management strategies. One of the initial plant physiological responses to salinity is a reduction of transpiration. This study used papaya as a model crop to better understand...

Essential oil-based products with broad plant disease control claims are commercially available and may be a practical alternative to copper fungicides for crop protection in organic mango orchards. We evaluated the disease control efficacy and crop safety of thyme oil, savory oil, and tree tea oil through replicated in vitro, in vivo (detached lea...

Background Many coastal areas of the world will be impacted by seawater intrusion inland exposing crops to increasing levels of soil salinity. Studies of salinity stress in horticultural crops, including papaya, invariably use NaCl as the salt source, which may not be indicative of seawater. Methods This study compared plant growth, physiological,...

Electrical plant signaling as a variation potential (VP) occurs in response to a wide range of stimuli, and it is associated with the induction of sudden changes in xylem pressure. Additionally, there is evidence that electrical potential (EP) of plants changes with changing soil water content. Therefore, the use of EP as a direct plant measurement...

Salinity is a major cause of abiotic stress to crops, including papaya (Carica papaya L.), one of the most cultivated fruit crops in tropical and subtropical regions. Two experiments were conducted to assess the response of 'Red Lady' papaya plants to salinity stress. In both experiments, salt stress was imposed by adding different concentrations o...

Avocado (P. americana Mill.) trees are classified into three botanical races, Mexican (M), Guatemalan (G), and West Indian (WI), each distinguished by their geographical centers of origin. While avocados are considered highly sensitive to flooding stress, comparative responses of the different races to short-term flooding are not known. This study...

Priming involves the exposure of plants to a mild stress to increase tolerance to a more intense stress in the future. Chemical priming with brassinosteroids reduces the negative effects of flooding on the physiology and survival of some plant species. Avocado trees are very susceptible to flooding, and flooding susceptibility is related to the roo...

Key message Relative susceptibility to laurel wilt among clonal, non-grafted avocado trees of different ecotypes is relate to the xylem vessel diameter, with larger vessels potentially allowing more rapid movement of fungal conidia in the transpiration stream, creating a potential for faster colonization of the vascular system by the pathogen. Abs...

Laurel wilt, caused by the fungus Raffaelea lauricola, is a lethal vascular disease that affects many members of the Lauraceae family, including avocado (Persea americana Mill.) trees. Previous studies have shown differences in laurel wilt susceptibility among genotypes, with cultivars of the West Indian (WI) race generally more susceptible to laur...

Laurel wilt, a lethal vascular wilt disease caused by the fungus Raffaelea lauricola, affects several tree species in the Lauraceae, including three Persea species. The susceptibility to laurel wilt of two forest tree species native to the southern United States, Persea borbonia and Persea palustris, and avocado, Persea americana cv Waldin, was exa...

Water uptake from the soil via a vapor pathway was tested. Viburnum suspensum L. seedlings were divided into: (1) irrigated, (2) drought with vapor, and (3) drought without vapor treatments. Each plant was placed into a larger bucket containing deuterium labelled water as a vapor source (vapor treatment) or no water (drought and irrigation treatmen...

This study aimed at comparing the growth and physiological changes in Jatropha curcas L. (jatropha or physic nut) young plants fertilized or not with a commercial product based on a micronutrient delivery system (MDS), under different doses of NPK. Measurements of growth, chlorophyll content, and leaf gas exchange were performed in the greenhouse,...

The effects of plant age at the time of mowing on sunn hemp (Crotalaria juncea L.) tissue decomposition, nitrogen (N) release, and fiber content in Krome very gravelly loam were assessed. Combined leaf and stem tissue from 42-, 77- or 112-day-old sunn hemp plants was placed in mesh bags and buried below the soil surface in the field. Bags were remo...

In vitro efficacy of the essential oils extracted from eight plant species was tested at application rates of 100, 250, 500, 1000, or 2000 µl/l for controlling fruit rots. Results showed a 100% reduction of mycelium growth of Colletotrichum, Fusarium, Phytophthora, Botryosphaeria after applying thyme or savory oils at all concentrations tested. Min...

Inhibitory effects of five different plant essential oils were assessed against papaya fruit decay caused by anthracnose. Essential oils were extracted from savory, thyme, cinnamon, mint, and lavender plants and chemical components of each oil were identified by GC-mass spectroscopy. The polymerase chain reaction (PCR) method using the internal tra...

We tested for isotope exchange between bound (immobile) and mobile soil water, and whether there is isotope fractionation during plant water uptake. These are critical assumptions to the formulation of the ‘two water worlds’ hypothesis based on isotope profiles of soil water. In two different soil types, soil‐bound water in two sets of 19‐l pots, e...

We tested the inhibitory properties of five different plant extracts to extend avocado fruit shelf life against anthracnose (Colletotrichum gloeosporioides Penz.). Essential oils were extracted from mint, savory, thyme, cinnamon and lavender and then analysed by gas chromatography-mass spectrometry. Carvacrol(71.2%) and thymol (73.3%) were the main...

In many parts of the world papaya (Carica papaya L.) is prone to hypoxic stress due to soil flooding as a result of severe storms or hurricanes. Two experiments were conducted to test the effects of root zone hypoxia on physiology, recovery and survival of papaya and to determine if negative impacts of root hypoxia can be reduced by chemically enri...

Papaya (Carica papaya L.) production in Florida is concentrated in areas with a high water table that are prone to flooding resulting from storms or hurricanes. This can limit production because the crop is sensitive to flooding stress. Studies were conducted to examine physiological responses of papaya to flooding a portion of or the entire root s...

Laurel wilt, caused by Raffaelea lauricola, is a destructive disease of avocado (Persea americana). The susceptibility of different cultivars and races was examined previously, but more information is needed on how this host responds to the disease. In the present study, net CO2 assimilation (A), stomatal conductance of H2O (gs), transpiration (E),...

Flooding for as little as 1 day has been shown to cause a dramatic decline in leaf gas exchange of potted papaya (Carica papaya L.) plants. However, the ability of papaya to recover from different durations of short-term flooding has not been reported. Therefore, a study was conducted to determine the effects of flooding duration on physiology, sur...

Para evaluar el efecto de diferentes tiempos de inundación total del sistema radical del cultivo de lechosa (Carica papaya L.) sobre aspectos fisiológicos y desarrollo del cultivo bajo condiciones controladas de invernadero, se realizó un ensayo en Homestead, Florida, EUA. Se utilizaron plantas del cultivar 'Red Lady' con 10 meses de edad sembradas...

Two experiments (Expts. 1 and 2) were conducted at different times with avocado (Persea americana Mill. cv. Choquette) trees in containers to test the effects of leaf pruning immediately after removing trees from short-term flooding on tree recovery. Trees in each experiment were divided into two flooding treatments: (1) flooded, or (2) non-flooded...

Flooding for as little as 1 day has been shown to cause a dramatic decline in leaf gas exchange of potted papaya (Carica papaya L.) plants. However, the ability of papaya to recover from different durations of short-term flooding has not been reported. Therefore, a study was conducted to determine the effects of flooding duration on physiology, sur...

Laurel wilt, caused by the fungus Raffaelea lauricola, has decimated members of the Lauraceae family in the southeastern United States since the early 2000s. It was detected in a Florida commercial avocado orchard in 2012, and poses a grave threat to the avocado industry. Affected trees wilt and usually die due to plugging of the vascular system. S...