Mapping agricultural responses to water supply shocks in large irrigation systems, southern India

Irrigated agriculture experienced a water supply shock during a drought in southern India in 2002-2003. In this paper, hotspots of agricultural change were mapped and put in the context of hydrology and water management. Time series of MODIS imagery taken every eight days before (2001-2002) and during (2002-2003) the supply shock were combined with agricultural census data to document changes in cropping patterns in four large irrigation projects in the downstream sections of the Krishna and Godavari River basins (total command area 18,287 km²). The area cropped in rice in the four irrigated command areas decreased by 32% during the drought year, and rice production in the two districts that experienced the largest flow reductions fell below production levels of 1980. The irrigation project that showed the largest change in double cropped area (−90%) was upstream of the Krishna Delta. In the Krishna Delta, large areas changed from rice-rice to rice-gram double cropping. Historical water management contributed to the vulnerability of rice production to drought: the main reservoir in the system was drained to dead storage levels by the end of each growing season over 1968-2000, with little carryover storage. The land cover change maps suggested that the lower Krishna Basin has experienced a “hard landing” during basin closure, and revised management strategies that account for the new flow regime will be required to maintain agricultural production during droughts.     

Oxidative stress indicators as selection tools for salt tolerance

Oxidative stress indicators, malondialdehyde (MDA) accumulation and chlorophyll retention, were tested as tools for salt‐tolerance screening in Chloris gayana (Kunth), a forage grass exhibiting inter‐ and intra‐cultivar variability in the response to salt stress. Three types of experimental system were compared, salt shock, gradual salt treatment and leaf segments floated on control and saline solutions. Results followed the same trend in the three systems, but leaf segments or gradually salinized plants are the most convenient. Lower mean MDA and higher mean chlorophyll content were found under salinity in cv. ‘Katambora’, which is considered, from previous field trials, to be more salt tolerant than cv. ‘Boma’. Nevertheless, chlorophyll content did not give consistent results in other tests and it is not recommended for selection purposes. Within cv. ‘Boma’, clones rating higher in a salt tolerance evaluation under greenhouse conditions had lower MDA content under salinity and lower mean MDA ratios between salt‐treated and control samples. The survival of 80‘Boma’ plants under increasing NaCl concentration was assessed and MDA was measured in the leaves of very plant before the final NaCl level was reached, to assess whether it was predictive of survival capability. MDA values were significantly lower in the group surviving longer, thus, a selection based on low MDA values would have enriched the original population with more tolerant individuals.     

Catalase peroxidase and IAA‐oxidase activities and O‐diphenolics contents in sunflower leaves grown with different boron levels

Cataiase, peroxidase and IAA‐oxidase activities, so as odiphenolics content in sunflower leaves grown in hydroponics with 4 B levels (0.05; 0.25; 0.5 and 2.0 ppm) were determined. The biochemical assays were made when visual symptons were clearly developed.

Cataiase activity significantly increased in B deficient leaves. Peroxidase, IAA‐oxidase activities and o‐diphenolics content did not significantly change with B levels. The lag period for IAA‐oxidase activity was significantly reduced in B deficient and toxic leaves with respect to the normal ones. These results are in accordance with the hypothesis that one of the B action could be to enhance cataiase activity, the “in vivo” decrease of H₂O₂ levels beeing the cause of the variation in other enzymatic activities related with that substrate.     

MODELING GROWTH AND ION CONCENTRATION OF LILIUM IN RESPONSE TO NITROGEN:POTASSIUM:CALCIUM MIXTURE SOLUTIONS

Nutrient solution composition plays an important role in root uptake rate due to interactions among nutrients and internal regulation. Studies to determine the optimum nutrient solution concentration are focused on individual ions, ignoring the adaptation mechanisms triggered by plants when growing in a varying external nutrient concentration. The objective of the present study was to determine the response in growth and tissue ion concentration of lilium cv. ‘Navona’ to nutrient mixtures of varying proportions of nitrogen (N), potassium (K⁺), and calcium (Ca²⁺) in solution using mixture experiments methodology in order to determine the optimum concentration. Bulbs of lilium were transplanted in plastic crates and drip-irrigated with the treatment solutions, which consisted of a mixture of N, K⁺, and Ca²⁺ whose total concentration was 340 mg L^?1 and minimum concentrations of each ion was 34 mg L^?1. Chlorophyll concentration (SPAD), shoot fresh weight (FW), leaf FW, and leaf area were measured 60 days after transplanting and ion analysis was performed on shoot tissues from selected treatments. Lilium exhibited a moderate demand for N and K⁺ (136–170 mg L^?1 N and 116–136 mg L^?1 K⁺) and a very low demand for Ca²⁺ (34–88 mg · L^?1). This low demand may be due to the remobilization of the nutrients stored in the bulbs. Integrating the predictions of the models estimated to produce >90% of maximum growth, the optimum nutrient solution should contain Ca²⁺ at a concentration between 34 and 126 mg · L^?1, K⁺ between 119 and 211 mg · L^?1, and N between 92 mg · L^?1 and 211 mg · L^?1. Increasing external N concentration affected internal N concentration but not internal K⁺ or Ca²⁺ concentrations, despite that the increase in external N was associated with a decrease in external K⁺ and Ca²⁺. Similar trends were observed for external K⁺ and Ca²⁺ concentration. In conclusion, lilium was able to maintain a relatively constant K⁺ and Ca²⁺ concentration regardless of the lower concentration in the nutrient solution when N was increased (similar response was observed for K⁺ and Ca²⁺) and it has a low Ca²⁺ demand and moderate N and K⁺ supply.     

Phenylalanine ammonia‐lyase activity and ortho‐diphenolic content with regard to boron nutrition in sunflower leaves.

Homogenates were prepared from the leaves of hydroponically cultivated sunflower (Helianthus annuus, L.) under deficient, normal and toxic B conditions and the phenylalanine ammonia‐lyase activity together with the ortho‐diphenolic and micronutrient content were measured every week from one month to flowering

The restoration of enzymatic activity on the exogenous addition of borate “in vivo”; was also studied.

Both B toxicity and deficiency resulted in increased phenylalanine ammonia‐lyase activity in the homogenates

The toxicity effect was early and sustained and the deficiency effect late and transitory. “In vitro”; borate addition to the reaction mixture did not significantly change the phenylalanine‐ammonia‐lyase activity in the homogenates.

There was no statistical correlation between the phenylalanine‐ammonia‐lyase activity and any micronutrient content in leaves.

A high accumulation of ortho‐diphenolics appeared in B‐deficient leaves only after 28 days of differential culture and may be responsible for the drop in phenylalanine‐ammonia‐lyase activity noted at this time.     

Changes induced by UV radiation during virgin olive oil storage

The effects of UV radiation on the chemical and sensory characteristics of virgin olive oils (cv. Arbequina and Picual) were assessed. Even small doses of UV radiation induced oxidation of the virgin olive oil samples. Total phenols and fatty acids contents decreased during the process as well as the intensity of the bitter and fruity sensory attributes, while the intensity of the rancid sensory attribute notably increased. Acetaldehyde, 2-butenal, 2-pentenal, octane, octanal, hexanal, nonanal, and 2-decenal were the volatile compounds most affected, showing an important increase during the irradiation process. Nonanal, hexanal, and pentanal showed high correlation with the rancid sensory attribute (90%, 86%, and 86%, respectively). 2-Decenal and nonanal concentrations allowed us to predict the alteration level of the samples by mean of multiple Ridge regression.     

Polyphenol oxidase activity and ortho‐diphenolic content in sunflower leaves in relation to boron nutrition.

Homogenates were prepared from the leaves of hydroponically cultivated sunflowers (Helianthus annuus, L.) under deficient, normal and toxic B conditions and the polyphenol oxidase activity together with the ortho‐diphenolic and micronutrient content was measured every week from one month to flowering.

B deficiency slightly depressed polyphenol oxidase activity and B toxicity decreased it significantly at all times, the response fitting a line versus the logarithm of the B concentration in solution. We found a positive correlation between polyphenol oxidase activity and the B content in leaves.

B action on enzymatic activity seemed not to be caused by direct interaction with substrates as the infiltration of B into deficient leaves did not restore the normal activity

According to our results we suggest that polyphenol oxidase activity may be a valid functional parameter to indicate the nutritional status of B in sunflower plants, if its specificity for B can be demonstrated.

The ortho‐diphenolic content did not change with the B levels used in our experiments. Neither did we find any correlation between enzymatic activity and the o‐diphenolic content of the leaves.     

2007KBDB全国长距离鸽王冠军—戈马利·佛布鲁根

在禽流感波及德国放飞的阴郁日子里，人们只能自行寻觅好消息。我们也是如此，因此我们便开始寻觅令人愉快的消息，而且也找到了。戈马利·佛布鲁根（Gommaire Verbruggen）告诉我们，他手里有一羽国家长距离鸽王的热门鸽选。认识戈马利的人就会晓得这并非是他的一时兴起之举。据他自己说，     

Endocrine response to lactate infusion during pentobarbitone anaesthesia

Lactic acid was infused iv in 6 Welsh ponies during pentobarbitone anaesthesia to investigate whether lactate triggers the pituitary-adrenal response to anaesthesia. Ponies were premedicated with acepromazine and anaesthesia was induced with pentobarbitone iv and maintained with pentobarbitone/oxygen for 2 h. Immediately after induction, 3% L(+) lactic acid infusion was started and adjusted to maintain plasma lactate concentration between 2 and 2.5 mmol/l. Cardiorespiratory function, temperature. PCV, plasma glucose, lactate, βendorphin, ACTH, cortisol and catecholamine concentrations were measured before, during and after anaesthesia. Hypothermia, reduced PCV, slight hypotension (minimum value 84 ± 6 mmHg 20 min after induction of anaesthesia), hyperoxia and marked bradypnoea developed during anaesthesia. No acidaemia occurred. Plasma glucose concentration increased at the end of anaesthesia. There were no changes in plasma ACTH, cortisol and catecholamine concentrations, but plasma & endorphin increased after induction until the end of anaesthesia. There was a correlation between plasma lactate and β-endorphin concentrations (P<0.001, r=0.63), which may suggest that lactate stimulates βendorphin release. Beta-endorphin was apparently secreted independently from ACTH and appears to be a sensitive marker of a stress response.