Under a pot-sand-culture test with varieties including ROC22 and TSC00-236,this study probes into the growth of sugarcane in terms of interaction of phosphorus and magnesium.It showed from the experiment that: phosphorus promotes significantly the accumulation of growth and biomass of two genotypes of sugarcane,while certain amount of magnesium facilitates the sugarcane accumulation growth and biomass.However,differences still exist between the two species.Root-shoot ratios of both the two varieties show a decreasing trend with the growth of phosphorus.Magnesium can increase plant’s root-shoot ratio,but too much of it inhibits sugarcane’s root growth.In the interaction of phosphorus and Magnesium,phosphorus is the main effect while magnesium is an aftereffect.In other words,the effect of phosphorus on the growth of sugarcane is more obvious than that of magnesium.Appropriate fertilization of magnesium helps increase output of sugarcane.

An analysis of the sugarcane industry in Xuwen County, Guangdong Province, was made not only on its present situation and developmental characteristics, but also on the existing problems. On this base, the general idea and corresponding strategies and measures for the County's sugarcane industry was put forward in this paper.

In order to clarify interactions between parasitic weed dodder (Cuscuta chinensis) and soybean (Glycine max L.), the degrade of damage caused by dodder parasitizing and related ecovphysiological response of soybean were evaluated in the fields. The growth of 14 soybean cultivars was investigated before and after being parasitized by dodder to estimate the damage degree, and one cultivar in each degree was selected for further determining the eco-physiological response to dodder in comparison with non-parasitized (CK). The result demonstrated that like the non-parasitized soybean, both growth and damage degree of soybean under parasitized with dodder were varied with the cultivars. Plants with high concentration of photosynthetic pigments, flavones, total N, and the higher net photosynthetic rate, were more easily parasitized and damaged with dodder, whereas the contents of soluble sugar were lowered. After soybean was parasitized with dodder, the trends of these index was adverse. These eco-physiological indexes were significantly varied with degree of soybean parasitized with dodder. The biomass of dodder parasitized in the severe damaged soybean cultivars were higher than that parasitized in weak damaged ones while the biomass of severe damaged soybean cultivars decreased more than that of weak damaged ones, therefore, the percentage of dodder biomass to the decreased biomass of soybean were higher in the weak damaged soybean cultivars. Both differences in growth differences of soybean cultivars parasitized by dodder and the damage degree of dodder on soybean, were related to photosynthesis, secondary metabolite, the transfer of assimilated products, and the total N content of soybean plants, and these differences became enlarged after being parasitized with dodder.

An experiment was conducted with 12 varieties(or lines) of E.arundinaceus including four BC2 lines and eight recurrent parents under field condition.The differences of the main physiological and biochemical characters among these 12 varieties(or lines) were studied.The results showed that the activity of acid invertase,ratio of activity of acid invertase to neutral invertase,chlorophyll content,permeability of cell cytoplasm membrane,bound water content,and ratio of bound water to free water content in leaves in BC2 lines were higher than those in their female parents(BC1 lines),indicating these characters were improved in the course of backcross;the malondialdehyde content,activity of nitrate reductvase,and superoxide dismutase content in leaves in all the BC2 lines were less than those in their female parents(BC1 lines),indicating these characters declined in the course of backcross;the soluble protein content,reducing sugar content,praline content,catalase content and peroxidase content in leaves in BC2 lines vary with each other,but these characters of YCE03-267 and YCE03-268(2 BC2 lines) derived from YCE01-48(BC1 line) were superior to those of their BC1 parents.

Ten BC_1 lines of Erianthus arundinaceus and their parents were selected to study the difference of physiological and biochemical characters.The proportion of bound water to free water content in leaves,regarded as a reasonable physiological index to identify drought resistance of sugarcane under normal water suplying,was tested for all the trial materials.Results showed that the proportions of bound water to free water content in all the BC_(1) lines were less than their female parent YC96-40.BC_(1)generation showed lower values of acid invertase activity in leaves compared with the female parent YC96-40,one of the internal and biochemical reasons for the brix and sucrose content were improved rapidly during the backcross process.By cluster analysis,the genetic distance between two parents was large for both on the proportion of bound water to free water content and on proline content in leaves.The genetic distance among most BC_(1) lines and the female parent YC96-40 was larger;for the proportion of bound water to free water content and smaller.

Ten BC1 lines of E. arundinaceus and their parents were selected to study the difference in agronomical and economical characters under field conditions. The results indicated that means of BC1 lines were in the range of two parents for most agronomical and economical characters. During the backcross process, rapid improvement was gained in such characters as Brix, polarization and sucrose content in cane juice. YCE01-80 had the highest value in these three indexes, which were 16.69%, 14.25% and 14.49%, respectively, and closed to the values of cultivated variety. The cane yields of most BC1 lines studied were higher than the parents, and YCE01-111 was 40.45% higher than the male parent CP84-1198 in cane yield. But improvement in thin and pithy stalks remained relatively slow. Characters including tillering rate, plant height, plant growing rate and millable stalks per hm2 presented diversity. By cluster analysis on cane yield, the genetic distance among most BC1 lines and parents was large. By making a comparison among the BC1 lines, preliminary results indicated that YCE01-111 was better than the others not only in such important agronomical characters as germination rate, tillering rate, plant height, plant growing rate and millable stalks per hm2, but also in such economical ones as the cane yield, brix, polarization, sucrose content in cane juice and fiber content of cane.

The effects of crop rotation of pineapples-sugarcane on sugarcane growth and soil microflora were studied.The results show that both of the sugarcane yield and sucroser content of cane in the crop rotation of pineapple-sugarcane are(higher) than those of the continuous cropping of sugarcane-sugarcane.Compared with other fields,the crop rotation field can improve the capability of aeration and water storage,accelerate the release of the quick effective nutrient,strengthen soil enzyme activity and increase the total quantity of microbe of soil.The beneficial ammonifier and the nitrifying bacteria double increase,while the unbeneficial anaerobic bacteria and denitrifying bacteria are inhibited.

The relationship among cane yield,sucrose content of cane juice and the main characters of the tested materials was analyzed by the correlation and path coefficient.The results were as follows: the correlation coefficients(0.0808 and(0.3658)) among stalk diameter,millable stalks per hm~2 and cane yield were small,but the direct effect(1.7935) of millable stalks per hm~2 to cane yield ranked the first,the stalk diameter ranked the second(1.5979);both the acid invertase activity and ratio of acid to neutral invertase activity in leaves showed negatively correlated with sucrose content of cane juice(-0.5593 and-0.6611,the latter was in a significant level),and the direct contribution of acid invertase activity to sucrose content of cane juice was important while the contribution of ratio of acid to neutral invertase activity was mainly indirect.

在不同的培养基上进行甘蔗心叶的组织培养,确定了适合愈伤组织生长繁殖的培养基构成,在此基础上研究了7个甘蔗基因型的组织培养特性,结果表明,供试材料的遗传基础是甘蔗心叶组织培养的重要制约因子,表现为不同甘蔗基因型之间的心叶脱分化速度、外植体褐化率、愈伤组织诱导率、生长速度和分化率均有明显的差异.

This paper introduces the latest advances in the research of biochemical functions of silicon in plants, including the basic researches on diatoms which are of referential value to researchers on higher plants, the biochemical functions of silicon in disease resistance, the role of silicon in alleviation of heavy metal toxicity, the effects of silicon on the growth and enzyme activities and the effects of silicon on the uptake and utilization of other nutrients.

采用溶液培养和组织培养2种方法分别对桂糖1号(GT1)、ROC10、Q75 3个甘蔗品种的幼苗和愈伤组织进行缺磷处理.结果表明,缺磷胁迫下,同一基因型甘蔗植株水平和细胞水平的保护酶活性变化的总体趋势具有一致性,但不同基因型甘蔗的保护酶活性的变化方式和变化幅度有所不同,与其耐低磷能力有一定的相关性:缺磷处理后,耐低磷能力强的GT1的保护酶活性较对照明显升高,耐低磷能力中等的ROC10的保护酶活性相对较稳定,而耐低磷能力弱的Q75的保护酶活性的升降幅度较大;其中SOD活性的变化趋势也可作为甘蔗品种耐低磷能力的评价指标之一.

Through the nutrient general survey of sugarcane field in Leizhou Peninsula and utilizing the statistical analysis method of mathematics, the relevant relation is concluded among nutrients, between the nutrient and economic properties. On this basis, the results show: With increased N,and raised pH, the sugarcane’s stem can be lengthened, and the stem lengthened can increase the weight of a single stem, industrial sugarcane yield and the sugar content in a remarkable way. With K, Mg increased, effective stems can be increased remarkably, and the effective stems’ increase can promote the raise of sugarcane yield strikingly, but lead to the decline of sugar content. Singular increase of the application of Mg will lead to the decline of sugar content. Therefore measures should be taken to increase the application of N, K with rational lime and phosphate fertilizer to promote the stem length, the single stem weight, the raise of effective stems in order that sugarcane yield can be raised; while controlling the application of Mg, the purpose of raising sugar content can be attained.

The effects of tillage and mulch methods on ratio of germination, ratio of tillering, net photosynthesis and production of sugarcane were investigated. The treatments included conventional tillage, all-direction deep loosening, shallow tillage after deep loosening, plastic film mulch and cane leaf mulch. The results shown that the mulching had the notable effect on sugarcane production, the plastic film mulch could increase the sugarcane production, and the treatments of cane leaf mulch with various tillage methods could increase sucrose content of sugarcane.

The results of the study on soil microflora in sugarcane experiment field under different mulching conditions showed that different mulching conditions provided a special ecological environment for microbes and changed some physical and chemical characteristics of the soil. During the period of sugarcane growth, the quantities of aerobic bacterium, fungi and actinomyces, and the total number of microbes in the soil covered by sugarcane leaf and plastic film increased more obviously than that of the soil without mulch. The quantities of ammonifiers and nitrifiers in the nitrogen physiological group increased significantly. The number variation of aerobic nitrogen-fixing bacterium was not obvious while the number of anaerobic bacterium decreased obviously . Under the mulching conditions, the effect of sugarcane leaf mulch was much better.

通过与世界主要食糖出口国的比较,发现我国糖业与国际先进糖业之间所存在的差距,进而分析得出造成我国糖业竞争力低下的最根本原因是管理体制问题、产权制度问题及政府和企业定位失误的结论.最后提出需要通过建立适合的调控机制、加快产权制度改革、发展规模制糖、降低生产成本、准确市场定位、调整产品结构、加强区域分工与合作等措施来提高我国糖业的综合竞争力.

Effect of water-holding agent on drought resistance in sugarcane was studied in the pot experiment under drought stress. Results showed that the application of water-holding agent significantly improved soil water content, relative leaf water content, and significantly decreased plasma membrane permeability, proline content and malondiadehyde content. T-test and variation range results showed that the poorer the drought-resistance was, the better the applied effect was. Correlation analysis results showed that increase in soil water contents and relative water contents of leaves was primary causes of increase in the drought resistance of sugarcane after the application of water-holding agent.