Effects of osmotic stress on polar auxin transport in Avena mesocotyl sections

Segments of mesocotyls of Avena sativa L. transported [1-14C]indol-3yl-acetic acid (IAA) with strictly basipetal polarity. Treatment of the segments with solutions of sorbitol caused a striking increase in basipetal auxin transport, which was greatest at concentrations around 0.5 M. Similar effects were observed with mannitol or quebrachitol as osmotica, but with glucose or sucrose the increases were smaller. Polar transport was still detectable in segments treated with 1.2 M sorbitol. The effects of osmotic stress on the polar transport of auxin were reversible, but treatment with sorbital solutions more concentrated than 0.5 M reduced the subsequent ability of mesocotyl segments to grow in response to IAA. The increased transport of auxin in the osmotically stressed segments could not be explained in terms of an increased uptake from donor blocks. The velocity of transport declined with higher concentrations of osmoticum. The reasons for the enhancement of auxin transport by osmotic stress are not known

A Hydrodynamical Model Of Pod-Set In Pigeonpea (Cajanuscajan)

In pigeonpeas (Cajanus cajan), most flowers are shed without setting pods. Pod-set is reduced by shading, defoliation and the presence of already developing pods, probably because of the reduced availability of assimilates or other nutrients. In pigeonpeas, unlike most leguminous crops, the average weight per pod of earlier and later formed pods is the same; this indicates that pod-filling is not limited by nutrient supply. Pod-set seems to be controlled in such a way that fewer pods develop than the plants are capable of filling. These processes can be represented by a simple working model, in which the assimilate supply corresponds to water in a reservoir, the axis of a branch or a raceme to a horizontal tube connected to the reservoir, and pods to containers of limited volume at a lower level; the connecting tubes between the axis and the 'pods' have an ascending limb, shorter than the descending limb to the pods, creating a siphon. 'Pods' can 'set' only when the level of water in the reservoir is higher than the threshold of the siphon; during the filling of earlier-set 'pods', the setting of other 'pods' is inhibited by the reduction of pressure within the axis. This model may provide a crude representation of mass flow within the phloem from sources to sinks; it also illustrates some of the hydrodynamical factors involved in competition among sinks

Growth, development and nutrient uptake in pigeonpeas (Cajanus cajan)

The growth and development of two early (Pusa ageti and T-21) and three mediumduration (ST-1, ICP-1 and HY-3C) cultivars of pigeonpea (Cajanus cajan (L.) Millsp.) were compared at Hyderabad, India, in 1974 and 1975; in 1976 cv. ICP-1 was studied. The pigeonpeas were grown on a Vertisol and on an Alfisol. The crop growth rate in the first 2 months was low. The maximum rate of 171 kg/ha/day was found in the fourth month of growth of cv. ICP-1 on Alfisol. The early cultivars, one of which (cv. Pusa ageti) was morphologically determinate, and the other (cv. T-21) indeterminate, did not differ in the proportion of dry matter partitioned into seeds. The mean dry weight of the ab ove-ground parts of the medium cultivars on Vertisol in 1975 was 8·45 t/ha, including 2·23 t/ha of fallen plant material. The mean harvest index (ratio of grain dry weight to total plant dry weight) of these cultivars was 0·24 excluding fallen material and 0·17 taking fallen material into account. Starch reserves were present in the stems during the vegetative phase, but disappeared during the reproductive phase. In 1974 the maximum leaf-area index on Vertisol was 3 and on Alfisol 12·7. The net assimilation rate tended to decline throughout the growth period, but in the medium cultivars increased at the end of the reproductive phase, probably because of photosynthesis in pod walls and stems

Pigeonpea (Cajanus cajan) as a Winter Crop in Peninsular India

Pigeonpeas (Cajanus cajan) are normally sown in June or July in India, at the beginning of the monsoon, but trials were carried out at Hyderabad by sowing in October or November as a winter crop. The duration of the crop, especially of the ‘medium’ and ‘late’ cultivars, was much reduced. In 1975–76, October-sown pigeonpeas gave yields comparable to those of the normal season but much lower yields were produced by planting in November 1975. ‘Medium’ and ‘late’ cultivars significantly outyielded early ones. Optimum plant populations for winter crops were 3–5 times higher than are normally used in the monsoon. Pigeonpeas at relatively high population densities could have considerable potential as a winter crop in peninsular India

Pulse Physiology Annual Report 1976-1977 Part 1 Pigeonpea Physiology

In this report we present results of work carried out between June 1976 and May 1977. The meteorological data for 1976/7 collected at the ICRISAT Agroclimatological observatory are shown in Fig.l. The dates of sowing, flowering and harvest of the kharif and rabi pigeonpea are indicateu in the figures. The most striking feature of the weather for this year wasunusually early cessation of the monsoon resulting in very 1 ittle rainfall in September. There was a cyclonic storm in the month of November

Second harvest yields of medium duration pigeonpeas (Cajanus cajan) in peninsular India

In Peninsular India medium duration pigeonpeas (Cajanus cajan) are normally sown soon after the onset of the monsoon, in June or July; they mature around December, when they are usually cut down and removed from the field. However, if they are harvested by ratooning or by picking the pods, the plants go on to produce a second flush of pods, which matures around March. In experiments conducted in four growing seasons at ICRISAT Center, second harvest yields were usually greater for non-ratooned than ratooned plants, and in experiments conducted on Vertisols they were greater for the plants ratooned high up in the plant than for those cut closer to the ground. Second harvest yields of non-ratooned plants without irrigation on Alfisols were on average 66% of the first harvest yields, but on Vertisols only 37%, in spite of the greater water-holding capacity of the latter. On Alfisols second harvest yields were approximately doubled by a single irrigation, but there was less response to irrigation on Vertisols. The poorer second harvest yields on Vertisols may have been due to the damaging effects of soil cracking on the root system of the plants. In non-ratooned plants from which the first and second flushes of pods were harvested together, yields were less than the total yield obtained from non-ratooned plants in two harvests, even though the yield loss, mainly due to pod shattering, was as little as 4% in one year. The taking of second harvests from pigeonpeas grown on Alfisols may have considerable potential as a method of obtaining additional yield for little extra cost

Teaching climate change and sustainability: A survey of teachers in England

This report shares detailed findings as to the current state of climate change and sustainability education in England in 2022-23, with a particular focus on teachers’ practice and professional development. The results reveal both strengths and gaps in the provision of climate change and sustainability education in England. The report serves as an evidence base for researchers, policymakers and practitioners who seek to support teachers to fulfil their important roles in society’s transformation to a sustainable future. UCL’s Centre for Climate Change and Sustainability Education (CCCSE) conducted a survey of teachers in England entitled ‘What do climate change and sustainability education have to do with me?’. Between October and December 2022, teachers were invited to respond to an online questionnaire about their views and experiences. Teachers were recruited through email lists, professional networks, social media and via the CCCSE website. The questionnaire investigated their teaching practice, professional development, and sense of confidence and preparedness to incorporate climate change and sustainability into their teaching. It included a range of question types and generated quantitative and qualitative data. The survey gathered 870 responses, with over two thirds (70.7%) teaching at secondary level, and geography (41.3%) and science (37.2%) being the most frequently reported subjects taught. Those who responded represented a wide range of teaching experience, from one year to 20+ years, with university-led PGCE programmes the most commonly reported route into teaching (87.2%). The significant majority of respondents were female (73.9%) and from white backgrounds (90.5%)

Iron chlorosis in chickpea (Cicer arietinum L.) grown on high pH calcareous vertisol

Genotypic differences exist in the sensitivity of cultivars of chickpea to iron deficiency. Sensitive cultivars exhibited typical iron deficiency symptoms when grown on calcareous soils with high pH. FeSO4 sprays (0.5%) corrected deficiency symptoms and increased yields by up to 50% in cultivars inefficient in iron utilization, but gave no increase in cultivars that were efficien