摘要:

AbstractFully expanded leaf occupying topmost position in a field grown pearl millet hybrid(BJ‐104)and its parents(J‐104and5141‐A)were analysed at weekly intervals for chlorophylls, Hill activity and phosphoenolpyruvate carboxylase activity. Large ontogenic drifts in these parameters, made the actual comparison between hybrid and parents, difficult. However, up to 52 d the hybrid leaf possessed considerably higher chlorophyll pigments than its parents. Amongst the inbreds, the male parent was initially better than the female parent while at later stages, the trend was reversed. Hill activity and PEPcase were more in the male than in the female parent and the hybrid followed the better parent. Rate limiting steps for productivity, measured as NAR (g dry weight)−1, were worked out in the female parent, using multiple regression and correlation analysis, and the significance of such an analysis is discussed in relation to plant produ

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAn experiment with eight cropping systems (pure and intercropping) with three levels of irrigations I0, I1and I2based on the physiological growth stages of safflower and chickpea was conducted during therabi(winter) season of 1983—84 and 1984—85. The eight cropping systems were CS1— sole chickpea, CS2— sole safflower, CS3— paired rows of chickpea, CS4— paired rows of safflower, CS5— chickpea + 50% safflower, CS6— safflower + 50% chickpea, CS7— chickpea + 75% safflower and CS8— safflower + 75% chickpea. Sole crop of chickpea always had higher yield component than inter‐cropping. However, none of the yield components in safflower was influenced by intercropping except number and weight of capsules per plant in 1983—84 only. With regard to levels of irrigation chickpea and safflower respo

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractPlant Growth after Application of CO2/HCO3to the RootsAfter applying H14CO3to the root system of summer wheat in hermetically sealed pots, absorption and incorporation of HCO3in the sugar‐, starch‐, and fibre‐fraction (approximately 50 % of the absorped14C) could be shown. This fraction reached 0.44–1.21 % of total C‐assimilation of the shoot during growing stage F9/F10 on the Feeke‐scala. 1/3 of the HCO3‐fraction resting in the soil was bound organically indicating that microorganisms may be able to utilize exogenous anorganic CO2/HCO3for their p

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00323.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe importance of incorporating compatible legumes into tropical grasslands has been highlighted by many researchers. Thus an experiment was conducted to identify optimum times of establishing tropical grasses and legumes in mixtures. The species selected were Guinea grass (Panicum maximum); Brachiaria (Brachiaria ruziziensis) and Green leaf (Desmodium intortum).The grasses were established along with and 4 and 8 weeks after the legume. The growth of the species was monitored for 16 weeks. The results identified the importance of prior establishment of the legume to overcome the competitive dominance of the herbage grasses. The growth form of the grasses also had an effect on the success of legume establishment. The legume had no adverse effect on the growth of the grasses.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00324.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractEffects of preceding “break crops” on winter wheat and influence of cultural practicesBetween 1979—83 there was tested the effect of 5 “break crops” (biennial alfalfa, clover‐grass, faba bean, winter‐rape, silomaize) on succeeding winter wheat and the interaction with changed cultural practices such as N‐fertilization and conventional or reduced primary tillage (plough ↔ rotary tiller).After the break crops wheat yield decreased within a range of 4 dt/ha as follows: alfalfa → beans → rape/ clover‐grass/maize. Raising N‐fertilization hardly allowed to improve the value of the break crops; most likely that of maize and with rotavating. Adaption of N‐dressings promised greater influence.The manner of primary tillage exerted stronger influence on the yield than the level of N‐fertilization. Concerning long‐term yield the rotary tiller equaled the plough after 4 break crops; after faba bean it was superior. Increasing N‐fertilization tendentially favoured the rotary tiller after bean, rape and maize. Using the rotary tiller, at beginning of growth there may be calculated on 15 % higher NO3‐values and/or higher N‐mineralization or N‐transformation.Eyespot disease could not be prevented sufficiently and purposefully by an other break crop, N‐fertilization or primary tillage. Recurrent rotav

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractInfluence of light quantity on growth and biological nitrogen fixation of white clover (Trifolium repensL.)The influence of photon irradiance (Ep; 100 to 500 μmol m−2s−1) and of the photoperiod (16 or 11 h) on growth and nitrogenase activity of nodulated white clover plants was studied in growth chambers at two nitrate levels (1.0 and 7.5 mM NO3−).Total dry mass production, the root proportion and nitrogenase activity increased with increasing Epand photoperiod. Nitrogenase activity generally increased proportionally to root mass. Only at low Ep(100 μmol m−2s−1) and under a short photoperiod (11 h) was the specific nitrogenase activity per unit root mass reduced. An abrupt change in Epled to a rapid and parallel change in nitrogenase activity and relative growth rate.A higher NO3−concentration in the nutrient solution (7.5 mM) led to a marked decrease in specific nitrogenase activity, but increased growth between 200 and 500 μmol m−2s−1during early development only. At 100 μmol m−2s−1, there was no growth response to nitrate, although its effect on nitrogenase activity was more marked than at a higher Ep.The results show that with changing light quantity, biological nitrogen fixation of white clover adapts to the existing demand for nitrogen and does not limit growth except during early development, even w

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractPeanuts (Arachis hypogaeaL.) which are commonly grown in intercropping systems often suffer from shading caused by the associated crop. Through this study an attempt has been made to estimate the effect of different levels of shade at different growth stages on crop yield. Field experiments were laid out during monsoon and winter seasons of 1985 and 1986 by creating artificial shading up to 25 and 50 per cent of the day/natural light at flowering‐pegging, pod filling and maturity stages of a Spanish bunch type peanut. Dry matter production has shown linear response to light intensity and due to 50 per cent shading it was reduced by 55 per cent. Vegetative growth rate during pod filling stage was very poor as a result of increase in shading at this stage. In shaded plants the nodulation was less and some reduction in chlorophyll content was also observed. However, oil content in kernel was not affected by shading. Shading caused significant reduction in pod number and kernel weight and thus there was decrease in pod yield. Flowering to pegging and pod filling stages seemed to be sensitive to shading while increase in shading at maturity stage did not cause any reduction in yield. It could be possible to obtain about 90 per cent pod yield by avoiding shading during flowering to pegging stage (45 DAS

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00327.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractAzolla is a small aquatic fern, that can be used as a green manure for irrigated rice before the transplanting of rice and under the rice crop. In a field experiment the interaction between Azolla application and rice spacing and its effect on the yield of rice in Azolla‐rice dual culture were studied. The rice was planted in double‐narrow‐rows ([53 + 13] × 12cm) and in the regular 20 × 20cm spacing. Azolla was grown together with rice twice and also incorporated into the soil twice. Double‐narrow‐row planting slightly increased the Azolla growth, but reduced the grain yield due to the reduction of tillering by stronger competition between the rice plants. The Azolla application had no effect with double‐narrow‐rows. With 20 × 20cm spacing two Azolla crops had an effect equivalent to 15kg NH4‐N/ha. An appreciable amount of Azolla‐N seemed to be available to the rice plants already 25 days

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractSeed proteins of a number of Egyptian, French, and British cultivars of flax have been separately extracted with buffer, and water and buffer respectively, and analyzed by slab electrophoresis: PAGE, SDS‐PAGE, and poro‐SDS‐PAGE (22.5%–10%), and by PAGIF. The protein patterns were compared to find out the best method to differentiate between flax cultivars.The results of the water extracts and the residue extracted with Tris/borate buffer and analyzed on SDS‐PAGE indicated that the approximate MWs of native albumins and globulins ranged from 4.2 to 1.2 and 7.6 to 1.6 × 104, respectively. It is also shown that SDS‐PAGE of globulins extracted with Tris/borate buffer are the method recommended for differentiation of flax cultivars.The data of the total proteins extracted with Tris/HCl buffer and analyzed on SDS‐PAGE under reducing and non‐reducing conditions exhibited 5 disulphide bonded bands which on reduction gave acidic subunits an

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00329.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe root morphology, drought tolerance and heat tolerance of theS. cereale×S. montanumcrossPermontra, six culturedS. cerealevarieties and the wild ryeS. montanumwere investigated and the use of membrane stability tests as a selection tool for drought and heat tolerance in rye evaluated.Root length, surface area and lateral density were measured on plants at the three leaf stage. Tolerance to drought, acute heat and chronic heat stress heat was assessed in culture chamber tests on control and drought or heat conditioned potted plants and membrane stability assessed by measuring electrolytic leakage.Permontrahad the most extensive root system and was the most drought tolerant variety measured.Permontrawas also the most tolerant of the varieties to chronic, though not to acute, heat stress. There was no correlation between drought tolerance in potted plants and membrane stability following either heat or dehydration stress

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1988.tb00330.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY