斑玉蕈菌丝体富集钙的研究

以斑玉蕈为试材，采用固体和液体培养方法对添加不同浓度氯化钙的菌丝体进行培养，研究了不同培养条件下钙对斑玉蕈菌丝体生长的影响，以及菌丝体对钙的富集与生物转化能力，以期为开发富钙斑玉蕈产品提供参考依据。结果表明：低浓度钙对斑玉蕈菌丝体的生长没有显著影响；固体培养条件下，钙浓度大于250 mg·L^-1时抑制菌丝体生长；而在液体培养条件下，钙浓度大于150 mg·L^-1时可抑制菌丝体生长。表明斑玉蕈菌丝体在不同培养条件下对钙的耐受性存在较大差异。液体培养条件下，发现随着钙浓度的提高，菌丝体中总钙含量也不断增加。在钙浓度为0～200 mg·L^-1时，有机态钙含量比例较高，表明菌丝体在该浓度范围内转化钙能力较强。当钙添加量为100 mg·L^-1时，其总钙含量为2 239.8 mg·kg^-1,钙富集率为1.83%,其中40.15%为有机态钙。     

Photosynthetic characteristics of subtending leaves and their relationships with soybean pod development under heat,drought and combined stresses

Soybean is usually grown under rain-fed conditions, and long-term drought stress often occurs with short-term heat stress. This study aimed to investigate changes in the photosynthetic characteristics of subtending leaves and their relationships with pod development under short-term heat, long-term drought and their combined stresses. Short-term heat stress lasted for 5 days began at R5 stage, and long-term drought stress lasted from R5 stage until maturity, respectively. No significant effect was observed on pod development under short-term heat stress alone due to unaffected net photosynthetic rate after treatment and PSII recovery after the heat stress release. Except that the reduction of sucrose content had been brought forward from 12 to 5 days after treatment under combined stresses, application of combined stresses caused similar responses to long-term drought stress alone on the photosynthetic characteristics of subtending leaves and pod development, but more pronounced under combined stresses. Reduced pod weight and seed weight per pod under long-term drought stress alone or combined stress due to a decrease in the net photosynthetic rate and production of sucrose and starch, especially after 19 days of treatment. Findings from this study demonstrate that under combined stress, long-term drought stress had a dominant effect on the photosynthetic performance of subtending leaves and pod development over short-term heat stress; moreover, even short-term heat stress also exacerbates the negative effects of long-term drought stress.     

贵州毕节植烟区土壤pH空间分布特征及对施肥的影响

以贵州省毕节植烟区为研究对象，探讨了毕节烟区土壤pH变异的主要影响因子，通过地统计插值方法获得了土壤pH空间变异特征，并对该地区以改良酸化土壤为目的的炭基有机肥施用适宜性等级进行了划分。毕节烟区土壤pH均值为6.5，其中大方和威宁两县的pH均值较低，仅为6.2，而织金、金沙和黔西三县的pH均值超过了7.0。因子分析表明，成土母岩和土壤类型是毕节烟区土壤pH变异性的主控因子。从空间分布特征来看，土壤pH整体分布呈现东部高于中西部，金沙县西北部、大方县东部、黔西县中部等地区pH均较高，而威宁县南部、赫章中北部和七星关区中西部等地区的土壤pH整体低于其他区域；土壤pH处于适宜等级(5.5相似文献