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Illumination-Independent Reflectance Information Acquirement for Leaf Water Potential Measurement on the Example of Satsuma Mandarin
75-79.Views:116Mandarin fruit sugar content can be increased when subjecting the satsuma mandarin tree (Citrus unshiu MARC. var. satsuma) to moderate water stress by mulching during the period of active sugar accumulation, thereby fruit quality improvement can be realized. In the frame of the precision agriculture production system, a non-destructive measuring method development became necessary based on remote sensing, field spectroscopy and image analysis, to be able to measure the degree of water stress. Large amount of visual information have been recorded at ground level, in near infrared, red and green channels by a false color digital camcorder designed specially for remote sensing applications. A method have been found to be able to calculate the absolute reflection of mandarin leaf surface by comparing leaf reflectance with known reference target reflectance, thereby established the basis of further studies in this topic. Leaf absolute reflection can be measured reliably, under variable natural illumination at field conditions. Functional correlation can be searched between visual information and leaf water potential measured by PMS pressure chamber.
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General defense system in the plant kingdom III.
45-54.Views:153Our observations regarding the symptoms not fitting into, significantly differing from the hypersensitive defense system, which we noticed during the judgment of several plant species, symptoms provoked on several million plants have constituted a unified entity. They have provided evidence for the existence of a different plant defense system. We called this so far unknown basic response of plants to biotic effects as general defense system. This system defends them from the attack of numerous microbe species in the environment.
The evolutionary intermediate phase between the general and the specific, the two defense systems is the susceptible host—pathogen relation. The vertical resistance system of plants escaping from the susceptible host—pathogen relation, based on specific hypersensitive reaction also suggested the existence of a more original, general defense system and the susceptible host—pathogen relation developed as a result of the collapse of that system.
The evolutionary relation of the two defense systems is proved by the only recessive inheritance of the older general defense system and in the majority of cases dominant hereditary course of the specific defense system. In our experiences, the modifying genes of the recessive general defense system, in most cases, are behind the specific defense systems, which are known to have monogenic dominant hereditary course and react with hypersensitive tissue destruction. This seemingly striking genetic fact is explained by the following: the general defense system less dependent on environmental effects regulates much faster pathophysiological reaction than the specific resistance genes strongly dependant on environmental effects coding dominant hypersensitive reaction.
The general and specific defense reactions, the processes excluding the microbes attacking plants with compacting of cell growth and tissue destruction, which mean two opposite strategies, building on and regulating each other constitute the entity of resistance to plant disease.
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Investigation of the cultivation value of old grapevine cultivars in Tokaj in 2004-2006
23-27.Views:173Most of the cultivars grown before the disaster of phylloxera in Tokaj can be found only in grapevine collections. The aim of our study was to determinate the cultivation values of six old grapevine cultivars of the wine-region, namely 'Balafánt', 'Budai gohér', 'Purcsin', 'Török gohér, 'Piros (red) furmint' and 'Változó (altering) furmint'. Based on the results of the investigations from 2004 to 2006 it can be concluded that among from the examined cultivars of Tokaj `Budai gohér', Turcsin' and 'Változó furmint' match the best with the technological and consumer requirements of recent days. However the yield of 'Budai gohér' in certain vintages is not acceptable and red wine cultivars are not permitted at this time in the wine-region, but in qualitative responses these presented steadily good data. On the other hand the lowest sugar content was measured and development of noble rot was not registered at all in case of Piros furmint' and `Balafánt'. Their spread in Tokaj is not probable.
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Effects of salinity stress induced by hot spring water on tomato growth, yield and fruit quality under hydroponic cultivation in Japan
23-28.Views:107The objective of this research was to test hot spring water as a source of salt to improve tomato quality under the hydroponic system. This research was conducted at Yamagata University, in Japan from February to July 2017. Salt stress was induced using salts of hot spring wastewater collected from Yupoka Onsen (Tsuruoka, Japan). The treatments were EC 2, 4, 8 12, and 16 mS/cm which were arranged in a Randomized Complete Block Design (RCBD) with five replications. Tomato plants were grown at EC 2 until flowering and then subjected to different EC concentrations until harvesting. The data were collected on plant growth parameters and fruit quality. Fruits were harvested at the red stage until the 5th truss. The results showed that fruits' Soluble Solids Content, organic acid, Nitrate contents and Sugar: Acid ratio increased significantly at EC 16 mS/cm and in the upper trusses compared to EC 2 and in the lower trusses. In contrast, fruit weight significantly decreased at EC 16 mS/cm and in upper trusses. Leaf thickness, size and SPAD, and specific leaf weight significantly declined at EC 16 mS/cm and upper leaves compared to EC 2 and in lower leaves. Plant height started to decline significantly after three weeks of treatment at EC 16 compared to EC 2.