Effect of temperature on seed development in jojoba (Simmondsia chinensis (Link) Schneider). I. Dry matter changes

1984 ◽  
Vol 35 (5) ◽  
pp. 685 ◽  
Author(s):  
IF Wardlaw ◽  
RL Dunstone

Growth of the capsule and seed of jojoba were followed from pollination to maturity at eight temperature regimens ranging from 15/10 to 36/31�C (8/16 h; photoperiod 16 h). There was an initial lag before the onset of rapid (linear) seed development, during which the capsule expanded, and this lag varied from 106 days at 15/10�C to 7 days at 36/31�C. The wax concentration in the seed was low during the initial stages of development, but reached a maximum when the seeds were 70-75% of their final dry weight. The maximum rate of dry matter accumulation in the seed increased with temperature up to 33/28�C but, because of the longer growth period at low temperature, seed size at maturity was greatest at 18/13�C. The current work suggests that prolonged periods with temperatures above 36/31�C, or below 15/10�C would be harmful to the development of jojoba seed. The high optimum temperature for growth rate of the seed (33/28�C) and sensitivity to a temperature of 15/10�C, puts jojoba into the same group as many subtropical species. However, the lower optimum temperature for seed weight at maturity (18/13�C) is close to that observed for the temperate cereals.

1969 ◽  
Vol 47 (7) ◽  
pp. 1143-1146 ◽  
Author(s):  
Holger Brix

Bud dormancy was induced in Douglas-fir seedlings 90 days after seed germination. Dry matter production of bud-dormant plants was determined for a 7-week growth period at five controlled temperatures from 2 to 24 °C. There was no significant temperature effect between 7 and 24 °C on total dry matter production, which at 2 °C was reduced. Dry weight of the root was affected more by temperature than that of the plant top. A pronounced temperature effect on dry matter production was found previously between 13 and 18 °C for plants in the stage of leaf production. This did not occur for bud-dormant plants because temperature effect on leaf production was not present. Net assimilation rates during bud dormancy were generally lower than during the stage of leaf production, especially at low temperature. This may have been caused by a reduced "sink" for use of photosynthates during bud dormancy.


1988 ◽  
Vol 68 (4) ◽  
pp. 935-940 ◽  
Author(s):  
M. TOLLENAAR ◽  
T. W. BRUULSEMA

The response of rate and duration of kernel dry matter accumulation to temperatures in the range 10–25 °C was studied for two maize (Zea mays L.) hybrids grown under controlled-environment conditions. Kernel growth rates during the period of linear kernel growth increased linearly with temperature (b = 0.3 mg kernel−1 d−1 °C−1). Kernel dry weight at physiological maturity varied little among temperature treatments because the increase in kernel growth rate with increase in temperature was associated with a decline in the duration of kernel growth proportional to the increase in kernel growth rate.Key words: Zea mays L, period of linear kernel dry matter accumulation, controlled-environment conditions, kernel growth rate


1977 ◽  
Vol 4 (5) ◽  
pp. 799 ◽  
Author(s):  
I Sofield ◽  
IF Wardlaw ◽  
LT Evans ◽  
SY Zee

Plants of five cultivars of wheat were grown under controlled-environmental conditions in order to analyse the effect of cultivar and of temperature and illuminance after anthesis on the accumulation of nitrogen and phosphorus by grains in relation to dry matter. The water relations of the grain during maturation were also examined, using calcium content as an index of water entry. The nitrogen and phosphorus contents of grains increased linearly throughout the grain growth period. The percentage of nitrogen and phosphorus in grains fell sharply during the first few days after anthesis but rose progressively thereafter. The higher the temperature, and the lower the illuminance, the higher was the percentage of nitrogen in the grain of all cultivars. Such conditions also reduce final grain size, but their effects on nitrogen concentration in the grain were apparent early in grain development. No evidence was found of a flush of nitrogen or phosphorus into the grain late in its development. Water entry into the grain continued at a steady rate until maximum grain dry weight was reached, then ceased suddenly. No evidence was found of an increased rate of water loss by the grain at that stage, and the rapid fall in water content at the cessation of grain growth may have been due to blockage of the chalazal zone of entry into the grain by the deposition of lipids. Accumulation of dry matter, nitrogen and phosphorus and entry of water into the grain all ceased at the time of lipid deposition in the chalazal zone.


1970 ◽  
Vol 50 (3) ◽  
pp. 233-247 ◽  
Author(s):  
D. B. FOWLER ◽  
R. K. DOWNEY

Self-pollinated seed from normal and erucic acid free plants of summer rapeseed (Brassica napus L.) was harvested at weekly intervals from pollination to maturity. Oven-dried whole seeds and their component parts were weighed and analyzed for oil content and fatty acid composition. Oil and dry matter accumulation followed sigmoidal patterns, most of the deposition occurring between 14 and 35 days after pollination (DAP). The relative contribution of the testa, endosperm and embryo to dry weight and oil content of whole seeds changed significantly during seed development. Oil content of the developing embryo varied from 22 to 44%, and the testa from 1.6 to 13%, although at maturity only 6 to 8% oil was found in the testa and adhering aleurone. The nucleate endosperm oil content was estimated to be low and in the order of 2 to 2.5%. In 7- to 14-day-old seeds the dry weight, oil content and fatty acid composition were largely determined by the testa and endosperm. From 14 to 21 DAP the testa and embryo were dominant and after 21 DAP the embryo was the controlling influence on the seed characteristics studied.Oils of the testa, nucleate endosperm and embryo differed in fatty acid composition. In seeds free of erucic acid, the ratios of the 18 carbon fatty acids of the embryo and testa remained nearly constant from 21 DAP to maturity. This suggested that the variation in fatty acid composition as well as oil content during seed development in this material was due to disproportionate changes in the contribution of the testa, nucleate endosperm and embryo. However, in developing seeds capable of producing erucic acid a change in the ratio of fatty acid synthesis occurred in both the testa and embryo.


1991 ◽  
Vol 116 (6) ◽  
pp. 981-986 ◽  
Author(s):  
F.J.A. Niederholzer ◽  
R.M. Carlson ◽  
K. Uriu ◽  
N.H. Willits ◽  
J.P. Pearson

A study was undertaken to determine the seasonal dynamics of leaf and fruit K content and the influence of tree K status and fruit growth on leaf and fruit K accumulation rates in French prune (Prunus domestics L. cv. d'Agen). Mature trees in a commercial orchard were treated with various rates of K2 SO4. (O to ≈20 kg/tree) in the fall. Fruit dry weight yield per tree at harvest and fruit K content were higher for high-K trees, but fruit percent K (by dry weight) was ≈1.0% for all trees. Leaf scorch and subsequent abscission severely reduced the canopy of K-deficient trees. Significant positive linear relationships between leaf and fruit K accumulation rates existed for the periods of 28 Apr.-28 May (May) and 28 May-7 July (June). A significant negative linear relationship existed between these two criteria from 7 July-3 Aug. (July). May (0.237 mg K per fruit-day) and July (0.267 mg K per fruit-day) mean fruit K accumulation rates were similar, but both were significantly higher (P = 0.001) than those for June (0.140 mg K per fruit-day). Mean leaf K accumulation rates for May (- 0.007 mg K per leaf-day) and July (-0.010 mg K per leaf-day) were similar, but both were significantly (P = 0.001) less than for June (0.005 mg K per leaf-day). Potassium per fruit accumulation was highest in trees with highest K status. Periods of net leaf K efflux and influx did not precisely correlate with fruit growth stages measured by fruit dry weight. The period of lowest fruit K accumulation (28 May-7 July) coincided with the period of maximum dry matter accumulation by the kernel. After 7 July, all increases in fruit dry weight and K content were due to mesocarp growth.


1989 ◽  
Vol 25 (3) ◽  
pp. 349-355 ◽  
Author(s):  
S. S. Parihar ◽  
R. S. Tripathi

SUMMARYThe response of chickpea to irrigation and phosphorus was studied at Kharagpur in Eastern India. Irrigation scheduling was based on the ratio between irrigation water applied and cumulative pan evaporation (ID/CPE), and had little effect on dry matter accumulation. Increasing the frequency and amount of irrigation reduced the number and dry weight of nodules per plant, which increased to a maximum 70 days after sowing and then declined. Irrigation significantly reduced grain yield as a result of excessive vegetative growth at the expense of pod formation. Application of phosphorus promoted nodulation and increased both nodule dry weight and the concentration of N, P and K in grain and stover. Uptake of N, P and K by the crop was also increased.


Author(s):  
Manpreet Jaidka ◽  
J.S. Deol ◽  
Ramanjit Kaur ◽  
R. Sikka

Effect of detopping and mepiquat chloride on morphological, physiological and yield attributes of soybean cultivar ‘SL 544’ was studied. A two year investigation was conducted at Punjab Agricultural University, Ludhiana, during kharif seasons of 2014 and 2015. The experiment was laid-out in randomized complete block design (RCBD) with eight treatments viz. control, detopping (removal of 4-5 cm apical portion of main stem) at 50-55 days after sowing (DAS), mepiquat chloride @ 200 ppm (50-55 DAS), mepiquat chloride @ 200 ppm (50-55 + 65-70 DAS), mepiquat chloride 250 ppm (50-55 DAS), mepiquat chloride @ 250 ppm (50-55 + 65-70 DAS), mepiquat chloride @ 300 ppm (50-55 DAS) and mepiquat chloride @ 300 ppm (50-55 + 65-70 DAS) with four replications. Detopping had a non-significant effect on leaf area index, SPAD value, PAR interception, abscission of reproductive parts, seeds per pod, 100-seed weight, pod length and stover yield of soybean. It significantly decreased plant height, increased total dry matter accumulation/plant, number of flowers and pods/plant, pod setting percentage and seed yield over control during 2014 and 2015. At crop harvest, detopping developed optimized source-sink relationship by means of distribution of total dry matter between stem, foliage and pods by 20.4, 14.9 and 64.6 % during 2014 while 22.6, 20.1 and 57.4 % during 2015, respectively. Mepiquat chloride posed a non-significant effect on plant height, PAR interception, number of flowers/plant, number of seeds/pod, pod length and stover yield of soybean but it significantly decreased leaf area index, abscission of reproductive parts while increased the dry matter accumulation/plant, number of pods/plant, 100-seed weight and seed yield relative to control. At harvest, two foliar applications of mepiquat chloride @ 250 ppm resulted in optimized source-sink relationship by the distribution of total dry matter among stem, foliage and pods by 20.6, 10.9 and 68.5 % during 2014 while 19.5, 7.6 and 72.9 % during 2015, respectively. Occurrence of more rainfall during 2015 as compared to 2014 caused mepiquat chloride to hike seed yield as compared to detopping which is clearly witnessed by increase in pod dry weight per plant during 2015 than 2014. Conclusively, both detopping and mepiquat chloride resulted in enhancement in source-sink relationship and seed yield of soybean.


1976 ◽  
Vol 16 (80) ◽  
pp. 387 ◽  
Author(s):  
P Farrington

Reproductive development, and the distribution of dry matter and nitrogen were followed in field plantings of Lupinus angustifolius cv. Uniharvest and L. cosentinii selection CB12 from the start of flowering until maturity. L. cosentinii (CBI 2) commenced flowering one week earlier, but developed one less order of inflorescences and fewer flowers than L. angustfiolius (Uniharvest) ; yet it set more pods and produced more seed. In both species seeds did not commence to fill until the leaves began to fall shortly after flowering ended. Seeds in pods on all orders of inflorescence filled concurrently. The increase in seed weight coincided with a rapid fall in the nitrogen content of other fractions of the tops.


1985 ◽  
Vol 65 (4) ◽  
pp. 867-877 ◽  
Author(s):  
LEONARD SAARI ◽  
SEPPO O. SALMINEN ◽  
ROBERT D. HILL

Developing triticale, wheat and rye grains were studied from 6 to 42 days postanthesis with respect to levels of sucrose and sucrose synthase activity. These were compared with levels of glucose and hexokinase activity as well as changes in dry weight and water content. Dry matter accumulation was linear in all cultivars and ceased at 26–34 days postanthesis, depending on the cultivar. Sucrose synthase activity was low in all tested cultivars at 3 days postanthesis and increased to near maximum levels by 15 days postanthesis. With the exception of triticale 6A190, maximum sucrose synthase activities were approximately 12 m units per seed and did not vary between cultivars. Triticale 6A190 had a maximum sucrose synthase activity of 16.5 m units per seed which occurred at about 21 days postanthesis. Sucrose synthase activity declined at maturity. Sucrose levels varied throughout kernel development. The extent of the variation differed amongst the tested cultivars. Triticale 6A190 had large fluctuations in sucrose level. Sucrose content changed from 1 mg per seed at day 12 to less than 0.1 mg/seed at day 18 to greater than 1 mg per seed at day 28. Hexokinase activity increased throughout kernel development with no substantial decline of activity at maturity. Glucose levels were highest during early kernel development and declined toward maturity. The variations in sucrose and sucrose synthase in triticale 6A190 suggest a malfunction in the metabolism of the line during kernel development. No direct relationship could be established, however, between these abnormalities and kernel shrivelling in 6A190.Key words: Sucrose, sucrose synthase, kernel development, triticale, wheat, rye, hexokinase


1979 ◽  
Vol 59 (3) ◽  
pp. 603-626 ◽  
Author(s):  
C. A. CAMPBELL ◽  
H. R. DAVIDSON

The effects of early moisture stress [tillering (Tg) to last leaf visible (LLV)], late moisture stress [LLV to anthesis (AN)], and three rates of N fertilizer (44, 88 and 132 kg N/ha) on the development and moisture use characteristics of spring wheat (Triticum aestivum L. ’Manitou’) were determined under simulated irrigation in the growth chamber at day/night temperatures of 27 °C/12 °C (T27/12) and 22 °C/12 °C (T22/12). Plant height was unaffected by N and by early stress, but was reduced by late stress. Number of tillers increased until LLV, then decreased sharply and remained constant to maturity. More tillers were initiated at T27/12 than at T22/12, but by maturity there was little difference. Leaf blade photosynthetic area reached its maximum at LLV, while the non-leaf blade photosynthetic area reached its maximum at AN and constituted 75% of the total photosynthetic area at the milk dough stage. Heads comprised no more than 9% of the photosynthetic area at any time. Total plant matter accumulated sigmoidally, but at T27/12 and low N rates, plants lost total dry weight after the milk dough stage. Dry matter of the vegetative plant parts increased until the milk dough stage, then stems in particular, and roots to a lesser extent, lost weight. Head weight increased linearly at about 17.5 mg/head/day. Dry matter accumulation was directly proportional to N applied, inversely related to temperature, temporarily retarded by early stress and markedly reduced by late stress. Although stems were the dominant vegetative dry matter sink, leaves were the dominant N sink. A combination of high temperature, high N and moisture stress resulted in a temporary loss of N from the plants between LLV and the milk dough stage. As maturation proceeded, N assimilates appeared to move from leaves to roots into stems and thence into heads. The average rate of N accumulation in the heads was 0.22 and 0.27 mg/head/day at T22/12 and T27/12, respectively. Some N was lost by denitrification. The amount and rate of evapotranspiration were directly proportional to N applied and in general inversely related to moisture stress. The rate of moisture use was generally more rapid at T27/12, but the amount used was no different from that at T22/12. Plants stressed early recovered and used water at the same rate as unstressed plants, but plants stressed late did not recover.


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