浅析水肥一体化模式对马铃薯生理、产量及水肥利用的影响

本文分析了水肥一体化模式对于马铃薯生理和产量以及水肥利用等方面的影响,通过对比分析确定最佳水肥一体化模式,有效提高马铃薯的产量,高效利用水肥资源,促进马铃薯生产工作健康发展。

马铃薯产量和生理对亏水和高频率喷灌的反应

在沙土地上种植马铃薯,只有配合适当的灌溉才可能高产质佳。了解最低需水量和掌握作物对水的胁迫作用的反应是很重要的。本项研究于1979年和1980年两个年度进行,目的是确定灌溉率对马铃薯表现的影响。处理在沙土地于冠层郁闭时开始实施,利用线性灌溉技术。接近喷灌源的日喷灌量是1.15E_t。处理实施两周后,开始在喷灌量最少的小区中观察植株对水的胁迫反应的症状。这些症状和正常植株比包括:植株变小,叶片变少,死叶增多和比叶重增大。块茎和地上部生长率随灌溉量增大而增大,从最小灌溉量到最大灌溉量分别为2.62～17.63克/米~2/天和-0.90～10.01克/米~2/天。同化产物向块茎的输送随灌溉量的增大而变小。试验结果表明,在沙土地上种植马铃薯,如果要避免产量下降和品质变劣,灌水量要接近估算的E_t。灌水量超过100％E_t不能增加产量。

Study on Daily Change in Photo-physiological Properties of Potato

[Objective]This study was to reveal the photo-physiological properties and suitable climate conditions for potato growth,so as to improve potato quality and yield by making use of the climate resources in Ningxia Hui Autonomous Region,to intensively develop the special agriculture there to enhance the economic benefit of local people.[Method]Using CIRASⅠ-Portable Photosynthesis System,we measured the daily change of photo-physiological indices of potato and further analyzed their relationship with daily weather change,and investigated the impacts of climate factors including atmospheric temperature,humidity,CO2 concentration and light intensity on various physiological indices of potato at key growth stages（flowering stage and stem-swelling stage）.[Results]The results showed that（1） humidity in experimental field assumed a ＂ U＂ type cosine variation curve,while photosynthetically active radiation and atmospheric temperature presented a reverse variation trend;（2） atmospheric CO2 concentration was positively correlated with intercellular CO2 concentration of potato cells,both assumed double ＂ W＂ type curve for daily change;（3） during growth period of potato,in the sunny days with appropriate relative humidity,physiological indices including photosynthetic rate,transpiration rate and stomatal conductance presented similar change law with environmental factor photosynthetically active radiation,all appearing an ＂ M＂ type curve with double peaks and a typical midday depression;（4） midday depression caused by to higher light intensity always appeared simultaneously with the maximum and minimum of air temperature.[Conclusion]Our results provided scientific basis for the large scale production of potato in Ningxia Hui Autonomous Region.

Regulation of Nitrogen on Potato under NaCl Stress

The effects of nitrogen on physiological and biochemical characteristics of potato cultivar Zihuabai under NaCl stress were studied in culture condition.The results show that,under NaCl stress,the contents of proline,chlorophyll and protein and root system vitality first increase and then decrease with the increase of nitrogen level,and reach the top under 4.17 mmol/L NH4NO3 level.Wherein,the contents of chlorophyll,protein and root system vitality are respectively 69.88%,13.07% and 59.29% higher than that of the control under 4.17 mmol/L NH4NO3 level;the activities of superoxide dismutase（SOD）and peroxidase（POD）increase generally under NaCl stress with the increase of nitrogen level,and reach the peaks [111.83 U/g and 25.467 U/（g·min）],which are 37.73% and 35.46% higher than that of control,at 6.25 mmol/L NH4NO3 level.

Changes in Physiological Indexes of SPDS Transgenic Potato Plants under Low Temperature Stress

Using potato plants overexpressing spermidine synthase（SPDS） gene as experimental materials, changes in chlorophyll content, malondialdehyde（MDA） content and superoxide dismutase（SOD） activity of potato leaves under low temperature stress were determined. According to the results, chlorophyll content of experimental plants showed a decreasing trend; MDA content of 01-47 was significantly higher than that of Atlantic; MDA content of 01-6 and 01-49 was significantly lower than that of Atlantic; SOD activity of 01-6 and 01-47 was higher than that of Atlantic. Potato lines 01-6 and 01-47 can be further cultivated to breed new cold-resistant potato varieties.

Susceptibility of Newly Introduced Potato Cultivars to Libya to Infection with Bacterial Soft Rot and the Associated Physiological Changes

Tuber slices of newly introduced potato cultivars （cvs） in Libya, namely Spunta, Pamela, Daisy, Daifla, Atlas and Apollina were tested for their susceptibility to soft rot bacterium （Erwinia carotovora subsp, carotovora）. Atlas cv was proved to be the most susceptible cv, meanwhile, Daisy cv was the most resistant one. The activities of pectolytic and oxidative enzymes in diseased tubers were profoundly higher than these in healthy ones. The highest enzymatic activities of pectin methyl esterase （PME） and polygalacturonase （PG） were observed in diseased tubers of Daifla cv. However, diseased tubers of Spunta gave the highest activities of polymethyl galacturonase （PMG）. On the other hand, the highest significant activities of the enzyme PME in healthy tubers was detected in Pamela cv compared to other cvs. Moreover, there were insignificant differences in PG and PMG enzymes activities between healthy tubers of the different cvs. The cv Daisy gave the highest activity of the enzyme peroxidase （PO） in diseased tubers, whereas the highest activity of enzyme polyphenol oxidase （PPO） was detected in infected tubers of Atlas cv. Concerning healthy tubers, the highest activities of enzymes PO and PPO were noticed in Atlas and Pamella cvs respectively as compared to other cvs. Electrolyte leakage from plant cells was estimated by measuring electrical conductivity as indicator for permeability changes in potato tissues. Values of electrolyte leakage in infected tubers of all tested cvs showed significant increase compared with those of healthy ones, especially, with the most susceptible one.